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The study aimed to evaluate the effectiveness of three plant extracts (cumin (Cuminum cyminum L.), peel fruit of pomegranate (Punica granatum), and fruit of black pepper (Piper nigrum L.)), against Pectobacterium carotovorum subsp. carotovorum (Pcc), a bacterium that causes potato tuber soft rot disease. This disease can result in significant losses to potato production and affects the quality of potatoes during storage, transit and shipment. To conduct the study, five isolates of the pathogenic bacterium were obtained from naturally infected potato tubers. According to the in vitro screening, the most virulence isolate Pcc2 was molecularly identified using 16S rRNA gene partial sequencing. Three plant extracts (cumin, pomegranate, and black pepper), were tested for their antibacterial activity against the bacterium using in vitro experiments. The results showed that all the three plants extract exhibited inhibition of the bacterial growth. Among the three-plant extract, pomegranate was found to have the best inhibitory effect on the bacterium (0.92 cm inhibition zone). Based on the findings of the in vitro experiments, the use of all extract at a concentration of 50 mg was recommended for controlling the soft rot disease in potato tubers during storage conditions. The data demonstrated that pomegranate extract was on the first ranking with bacterial growth reduction percentage estimated (1.4 mm), followed by cumin extract with growth reduction estimated (0.92). The data revealed that all of the tested plant extracts were able to reduce the severity of the disease. Of all the extracts, pomegranate extract showed the highest reduction in disease severity (91.3%). It is evident that the treatments with pomegranate, black pepper, and cumin consistently led to an increase in total phenol content over the course of 21 days. Treatments with methanolic extract of pomegranate, black pepper, and cumin lead to varying degrees of increased peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities over the course of the experiment. The data shows that the effectiveness of these treatments generally increases with time. In conclusion, the study showed that all plants extract tested herein has the potential to control potato tuber soft rot disease, which is a major problem affecting potato production. [ABSTRACT FROM AUTHOR]

Dracocephalum kotschyi Boiss., an endemic and endangered medicinal and aromatic plant in Iran, showcases distinct botanical characteristics and therapeutic promise. According to the IUCN grouping criteria, this plant is facing challenges due to overcollection from its natural habitats. To address this issue, there is an increasing inclination towards cultivating this species within agricultural systems. This study aimed to evaluate the impact of applying Fe2O3 nanoparticles (NPs) at varying concentrations (50, 100, and 200 mg L-1), as well as bulk Fe2O3 at the same concentrations, on the growth, essential oil production, antioxidant capacity, total phenol, and flavonoid content of D. kotschyi. The foliar application of 100 and/or 200 mg L-1 of Fe2O3 NPs resulted in the greatest leaf length and dry weight, while Fe2O3 NPs at the level of 100 mg L-1 led to the highest leaf/stem ratio. Additionally, spraying 200 mg L-1 of Fe2O3 NPs and all concentrations of bulk Fe2O3 positively impacted chlorophyll and carotenoid levels. Both nano and bulk Fe2O3 supplements stimulated H2O2 production and subsequently enhanced enzymatic antioxidant activity. The use of 50 mg L-1 of Fe2O3 NPs resulted in the highest flavonoid content and non-enzymatic antioxidant activity. Meanwhile, the highest essential oil content and yield was achieved by the application of 50 and/or 100mg L-1 Fe2O3 NPs. The addition of low concentration of Fe2O3 NPs (50 mg L-1) resulted in a significant increase in the concentration of geranial, while a higher supply of Fe2O3 NPs (200 mg L-1) significantly decreased the percentage of neral in the essential oil. Overall, the application of Fe2O3 NPs demonstrated significant potential for increased biomass, enhanced yield, essential oil production, and phytochemical attributes. The findings highlight the versatility of Fe2O3 NPs at optimal concentrations, acting as both a nano-fertilizer and a nano-inducer, promoting the production and accumulation of valuable secondary metabolites in plants. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia-lyase (PAL) acts as the rate-limiting enzyme for anthocyanin biosynthesis through the phenylpropanoid pathway, a crucial component of plant secondary metabolism. The PAL gene family plays a crucial role in plants' defense and stress responses, but its in silico identification and expression analyses in Brassica oleracea under different abiotic stresses remain unexplored. In this study, nine BolPAL, seven BrPAL, four AtPAL, and seventeen BnPAL genes were obtained from the genomes of B. oleracea, Brassica rapa, Arabidopsis thaliana, and Brassica napus, respectively. Segmental duplication and purifying selection are the causes of the BolPAL gene's amplification and evolution. The BolPAL genes with comparable intron–exon architectures and motifs were grouped together in the same clade. Three categories comprised the cis-regulatory elements: abiotic stressors, phytohormones, and light. According to the results of the qRT-PCR experiments, the majority of the BolPAL genes were expressed highly under MeJA, a low temperature, and a high temperature, and they were downregulated under ABA. Under white light (100 µmol m−2 s−1) with 50, 100, or 150 µmol m−2 s−1 far-red (FR), only a small number of the PAL genes were expressed at 50 and 100 µmol m−2 s−1 FR, while the majority of the PAL genes were slightly elevated at 150 µmol m−2 s−1 FR. This work offers a theoretical foundation for molecular breeding research to investigate the role of BolPAL genes and their role in anthocyanin biosynthesis. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) catalyzes the deamination of phenylalanine, which is the initial step in the biosynthesis of phenylpropanoids. It serves as a crucial enzyme that facilitates the transfer of carbon from primary to secondary metabolism in plants. Duckweed is regarded as a promising chassis plant in synthetic biology research and application, due to its being rich in secondary metabolites and other advantages. The genes encoding PAL in Spirodela polyrhiza (L.) Schleid, the giant duckweed, were investigated in this study. Three SpPAL genes (SpPAL1–SpPAL3) were identified and cloned. All of them were successfully expressed in E. coli, and their recombinant proteins all showed PAL activity. In addition, SpPAL1 and SpPAL2 proteins could also utilize tyrosine as substrate, although the activity was low. A qRT-PCR analysis demonstrated that the expression of SpPAL3 was most pronounced in young fronds. It was found that the expression of SpPAL1 and SpPAL3 was significantly induced by MeJA treatment. Overexpression of SpPAL3 in Lemna turionifera inhibited the growth of fronds and adventitious roots in the transgenic plants, indicating the importance of SpPAL3 in duckweed besides its involvement in the secondary metabolism. [ABSTRACT FROM AUTHOR]

Plants encounter many biotic entities, such as fungi, bacteria, and nematodes, which induce biotic stress that disrupts normal metabolism and limits the growth and productivity of plants. Currently, the use of plant growth-promoting bacterial endophytes instead of synthetic fungicides is intriguingly eco-friendly. An in vitro and in vivo antagonistic approach using Bacillus amyloliquefaciens RaSh1 was used to mimic the pathogenic effect of Alternaria alternata. The results showed that B. amyloliquefaciens significantly inhibited pathogenic fungal growth in vitro. Further, Capsicum annuum L. (pepper plants) were grown and subjected to inoculation with B. amyloliquefaciens and infected with A. alternata, and then the growth attributes, photosynthetic pigments, physio-biochemical parameters, and the level of endogenous phytohormones were assessed. Under the pathogen attack, the main responses, such as plant length, total fresh and dry weights, total chlorophylls, and pigments, were reduced, accompanied by increases in H2O2. As well, infection of pepper with A. alternata caused downregulation in the plant hormonal system by significantly decreasing gibberellins, indole-3-acetic acid, abscisic acid, as well as cytokinin concentrations. Although, with B. amyloliquefaciens application, an enhancement in growth, photosynthetic pigments, proline, thiol content, phenylalanine ammonia-lyase, and peroxidase in pepper plant leaves appeared while the content of H2O2 decreased. Endogenous phytohormones were found to be upregulated in B. amyloliquefaciens-inoculated and diseased plants. The current study found that B. amyloliquefaciens RaSh1 rescued pepper plant growth by modulating antioxidant defense and regulating hormones, and could be used to control A. alternata in an environmentally friendly manner while maintaining sustainable agriculture and food security. [ABSTRACT FROM AUTHOR]

Abstract Background In the past two decades, the impacts of Helium-Neon (He–Ne) laser on stress resistance and secondary metabolism in plants have been studied, but the signaling pathway which by laser regulates this process remains unclear. Therefore, the current study sought to explore the role of RBOH-dependent signaling in He–Ne laser-induced salt tolerance and elicitation of secondary metabolism in Salvia officinalis. Seeds were primed with He–Ne laser (6 J cm− 2) and peroxide hydrogen (H2O2, 5 mM) and 15-old-day plants were exposed to two salinity levels (0, 75 mM NaCl). Results Salt stress reduced growth parameters, chlorophyll content and relative water content (RWC) and increased malodialdehyde (MDA) and H2O2 contents in leaves of 45-old-day plants. After 48 h of salt exposure, higher transcription levels of RBOH (encoding NADPH oxidase), PAL (phenylalanine ammonia-lyase), and RAS (rosmarinic acid synthase) were recorded in leaves of plants grown from seeds primed with He–Ne laser and/or H2O2. Despite laser up-regulated RBOH gene in the early hours of exposing to salinity, H2O2 and MDA contents were lower in leaves of these plants after 30 days. Seed pretreatment with He–Ne laser and/or H2O2 augmented the accumulation of anthocyanins, total phenol, carnasol, and rosmarinic acid and increased total antioxidant capacity under non-saline and more extensively at saline conditions. Indeed, these treatments improved RWC, and K+/Na+ ratio, enhanced the activities of superoxide dismutase and ascorbate peroxidase and proline accumulation, and significantly decreased membrane injury and H2O2 content in leaves of 45-old-day plants under salt stress. However, applying diphenylene iodonium (DPI as an inhibitor of NADPH oxidase) and N, N-dimethyl thiourea (DMTU as a H2O2 scavenger) after laser priming reversed the aforementioned effects which in turn resulted in the loss of laser-induced salt tolerance and secondary metabolism. Conclusions These findings for the first time deciphered that laser can induce a transient RBOH-dependent H2O2 burst, which might act as a downstream signal to promote secondary metabolism and salt stress alleviation in S. officinalis plants.

Background: In the past two decades, the impacts of Helium-Neon (He–Ne) laser on stress resistance and secondary metabolism in plants have been studied, but the signaling pathway which by laser regulates this process remains unclear. Therefore, the current study sought to explore the role of RBOH-dependent signaling in He–Ne laser-induced salt tolerance and elicitation of secondary metabolism in Salvia officinalis. Seeds were primed with He–Ne laser (6 J cm− 2) and peroxide hydrogen (H2O2, 5 mM) and 15-old-day plants were exposed to two salinity levels (0, 75 mM NaCl). Results: Salt stress reduced growth parameters, chlorophyll content and relative water content (RWC) and increased malodialdehyde (MDA) and H2O2 contents in leaves of 45-old-day plants. After 48 h of salt exposure, higher transcription levels of RBOH (encoding NADPH oxidase), PAL (phenylalanine ammonia-lyase), and RAS (rosmarinic acid synthase) were recorded in leaves of plants grown from seeds primed with He–Ne laser and/or H2O2. Despite laser up-regulated RBOH gene in the early hours of exposing to salinity, H2O2 and MDA contents were lower in leaves of these plants after 30 days. Seed pretreatment with He–Ne laser and/or H2O2 augmented the accumulation of anthocyanins, total phenol, carnasol, and rosmarinic acid and increased total antioxidant capacity under non-saline and more extensively at saline conditions. Indeed, these treatments improved RWC, and K+/Na+ ratio, enhanced the activities of superoxide dismutase and ascorbate peroxidase and proline accumulation, and significantly decreased membrane injury and H2O2 content in leaves of 45-old-day plants under salt stress. However, applying diphenylene iodonium (DPI as an inhibitor of NADPH oxidase) and N, N-dimethyl thiourea (DMTU as a H2O2 scavenger) after laser priming reversed the aforementioned effects which in turn resulted in the loss of laser-induced salt tolerance and secondary metabolism. Conclusions: These findings for the first time deciphered that laser can induce a transient RBOH-dependent H2O2 burst, which might act as a downstream signal to promote secondary metabolism and salt stress alleviation in S. officinalis plants. [ABSTRACT FROM AUTHOR]

Aim This study aimed to overproduce industrially relevant and safe bio-compound trans-cinnamic acid (tCA) from Photorhabdus luminescens with deletion strategies and homologous expression strategies that had not been applied before for tCA production. Methods and Results The overproduction of the industrially relevant compound tCA was successfully performed in P. luminescens by deleting stlB (TTO1ΔstlB) encoding a cinnamic acid CoA ligase in the isopropylstilbene pathway and the hcaE insertion (knockout) mutation (hcaE::cat) in the phenylpropionate catabolic pathway, responsible for tCA degradation. A double mutant of both stlB deletion and hcaE insertion mutation (TTO1DM ΔstlB-hcaE::cat) was also generated. These deletion strategies and the phenylalanine ammonium lyase-producing (PI-PAL from Photorhabdus luminescens) plasmid, pBAD30C, carrying stlA (homologous expression mutants) are utilized together in the same strain using different media, a variety of cultivation conditions, and efficient anion exchange resin (Amberlite IRA402) for enhanced tCA synthesis. At the end of the 120-h shake flask cultivation, the maximum tCA production was recorded as 1281 mg l−1 in the TTO1pBAD30C mutant cultivated in TB medium, with the IRA402 resin keeping 793 mg l−1 and the remaining 488 mg l−1 found in the supernatant. Conclusion TCA production was successfully achieved with homologous expression, coupled with deletion and insertion strategies. 1281 mg l−1is the highest tCA concentration that achieved by bacterial tCA production in flask cultivation, according to our knowledge. [ABSTRACT FROM AUTHOR]

This study assessed the leaf pigments and the activity of peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase enzymes in soybean local cultivars, i.e., Genetic-1, Tomaris, Baraka, Nafis, and Sochilmas, under the influence of the phytopathogenic fungus Alternaria alternata. In local soybean (Glycine max L.) cultivars during the budding and flowering periods, the A. alternata micromycetes influenced and decreased the chlorophyll a and b index compared with the control, validating the relationship of soybean leaf chlorophyll with the phytopathogenic micromycetes. Compared with the control variant, carotenoid content in the leaves of some soybean cultivars increased to varying degrees in variants with phytopathogenic micromycetes while decreasing in other genotypes to varying degrees. An outcome of the study revealed that the amount of leaf pigments in local soybean varieties infected with the phytopathogenic micromycete A. alternata is higher during the plant’s flowering than during its budding period. Compared with other soybean cultivars, the Baraka and Nafis appeared with enhanced peroxidase enzyme activity by the artificial exposure to the A. alternata fungus. The results further revealed that polyphenol oxidase enzyme activity also increased by 117.7% and 152.0% in the cultivars Tomaris and Baraka, respectively, under the influence of A. alternata micromycetes compared with the control. The activity of phenylalanine ammonia-lyase enzyme was higher in the soybean cultivars Tomaris and Nafis under the influence of A. alternata than in other cultivars and the control. The activity of the peroxidase, polyphenol oxidase enzyme, and phenylalanine ammonia-lyase heightened in all the soybean cultivars under the influence of the phytopathogenic micromycete A. alternata compared with the control treatment. [ABSTRACT FROM AUTHOR]

Pomegranate arils pose a significant challenge when it comes to preserving their nutritional value and preventing microbial contamination. This study aimed to explore the impact of thymol fumigation and active modified atmosphere packaging (MAP) on enzymatic activity and microbial contamination prevention in pomegranate arils. The results indicated that arils stored in a high O2 atmosphere (HO2A) with thymol had notably different catalase (CAT) and peroxidase (POD) activity levels compared to other treatments. These arils exhibited the highest CAT activity and the lowest POD activity. The highest phenylalanine ammonia-lyase (PAL) activity was observed in arils stored in HO2A with thymol, although it was not significantly different from those stored in a high CO2 atmosphere (HCO2A) with thymol (P

Dracocephalum kotschyi Boiss., an endemic and endangered medicinal and aromatic plant in Iran, showcases distinct botanical characteristics and therapeutic promise. According to the IUCN grouping criteria, this plant is facing challenges due to overcollection from its natural habitats. To address this issue, there is an increasing inclination towards cultivating this species within agricultural systems. This study aimed to evaluate the impact of applying Fe2O3 nanoparticles (NPs) at varying concentrations (50, 100, and 200 mg L-1), as well as bulk Fe2O3 at the same concentrations, on the growth, essential oil production, antioxidant capacity, total phenol, and flavonoid content of D. kotschyi. The foliar application of 100 and/or 200 mg L-1 of Fe2O3 NPs resulted in the greatest leaf length and dry weight, while Fe2O3 NPs at the level of 100 mg L-1 led to the highest leaf/stem ratio. Additionally, spraying 200 mg L-1 of Fe2O3 NPs and all concentrations of bulk Fe2O3 positively impacted chlorophyll and carotenoid levels. Both nano and bulk Fe2O3 supplements stimulated H2O2 production and subsequently enhanced enzymatic antioxidant activity. The use of 50 mg L-1 of Fe2O3 NPs resulted in the highest flavonoid content and non-enzymatic antioxidant activity. Meanwhile, the highest essential oil content and yield was achieved by the application of 50 and/or 100 mg L-1 Fe2O3 NPs. The addition of low concentration of Fe2O3 NPs (50 mg L-1) resulted in a significant increase in the concentration of geranial, while a higher supply of Fe2O3 NPs (200 mg L-1) significantly decreased the percentage of neral in the essential oil. Overall, the application of Fe2O3 NPs demonstrated significant potential for increased biomass, enhanced yield, essential oil production, and phytochemical attributes. The findings highlight the versatility of Fe2O3 NPs at optimal concentrations, acting as both a nano-fertilizer and a nano-inducer, promoting the production and accumulation of valuable secondary metabolites in plants.

Abstract Background This study aimed to investigate the alterations in biochemical and physiological responses of oat plants exposed to antimony (Sb) contamination in soil. Specifically, we evaluated the effectiveness of an arbuscular mycorrhizal fungus (AMF) and olive mill waste (OMW) in mitigating the effects of Sb contamination. The soil was treated with a commercial strain of AMF (Rhizophagus irregularis) and OMW (4% w/w) under two different levels of Sb (0 and 1500 mg kg−1 soil). Results The combined treatment (OMW + AMF) enhanced the photosynthetic rate (+ 40%) and chlorophyll a (+ 91%) and chlorophyll b (+ 50%) content under Sb condition, which in turn induced more biomass production (+ 67–78%) compared to the contaminated control plants. More photosynthesis in OMW + AMF-treated plants gives a route for phenylalanine amino acid synthesis (+ 69%), which is used as a precursor for the biosynthesis of secondary metabolites, including flavonoids (+ 110%), polyphenols (+ 26%), and anthocyanins (+ 63%) compared to control plants. More activation of phenylalanine ammonia-lyase (+ 38%) and chalcone synthase (+ 26%) enzymes in OMW + AMF-treated plants under Sb stress indicated the activation of phenylpropanoid pathways in antioxidant metabolites biosynthesis. There was also improved shifting of antioxidant enzyme activities in the ASC/GSH and catalytic pathways in plants in response to OMW + AMF and Sb contamination, remarkably reducing oxidative damage markers. Conclusions While individual applications of OMW and AMF also demonstrated some degree of plant tolerance induction, the combined presence of AMF with OMW supplementation significantly enhanced plant biomass production and adaptability to oxidative stress induced by soil Sb contamination.

Abstract Background Saccharum spontaneum L. is a closely related species of sugarcane and has become an important genetic component of modern sugarcane cultivars. Stem development is one of the important factors for affecting the yield, while the molecular mechanism of stem development remains poorly understanding in S. spontaneum. Phenylalanine ammonia-lyase (PAL) is a vital component of both primary and secondary metabolism, contributing significantly to plant growth, development and stress defense. However, the current knowledge about PAL genes in S. spontaneum is still limited. Thus, identification and characterization of the PAL genes by transcriptome analysis will provide a theoretical basis for further investigation of the function of PAL gene in sugarcane. Results In this study, 42 of PAL genes were identified, including 26 SsPAL genes from S. spontaneum, 8 ShPAL genes from sugarcane cultivar R570, and 8 SbPAL genes from sorghum. Phylogenetic analysis showed that SsPAL genes were divided into three groups, potentially influenced by long-term natural selection. Notably, 20 SsPAL genes were existed on chromosomes 4 and 5, indicating that they are highly conserved in S. spontaneum. This conservation is likely a result of the prevalence of whole-genome replications within this gene family. The upstream sequence of PAL genes were found to contain conserved cis-acting elements such as G-box and SP1, GT1-motif and CAT-box, which collectively regulate the growth and development of S. spontaneum. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that SsPAL genes of stem had a significantly upregulated than that of leaves, suggesting that they may promote the stem growth and development, particularly in the + 6 stem (The sixth cane stalk from the top to down) during the growth stage. Conclusions The results of this study revealed the molecular characteristics of SsPAL genes and indicated that they may play a vital role in stem growth and development of S. spontaneum. Altogether, our findings will promote the understanding of the molecular mechanism of S. spontaneum stem development, and also contribute to the sugarcane genetic improving.

Background: This study aimed to investigate the alterations in biochemical and physiological responses of oat plants exposed to antimony (Sb) contamination in soil. Specifically, we evaluated the effectiveness of an arbuscular mycorrhizal fungus (AMF) and olive mill waste (OMW) in mitigating the effects of Sb contamination. The soil was treated with a commercial strain of AMF (Rhizophagus irregularis) and OMW (4% w/w) under two different levels of Sb (0 and 1500 mg kg−1 soil). Results: The combined treatment (OMW + AMF) enhanced the photosynthetic rate (+ 40%) and chlorophyll a (+ 91%) and chlorophyll b (+ 50%) content under Sb condition, which in turn induced more biomass production (+ 67–78%) compared to the contaminated control plants. More photosynthesis in OMW + AMF-treated plants gives a route for phenylalanine amino acid synthesis (+ 69%), which is used as a precursor for the biosynthesis of secondary metabolites, including flavonoids (+ 110%), polyphenols (+ 26%), and anthocyanins (+ 63%) compared to control plants. More activation of phenylalanine ammonia-lyase (+ 38%) and chalcone synthase (+ 26%) enzymes in OMW + AMF-treated plants under Sb stress indicated the activation of phenylpropanoid pathways in antioxidant metabolites biosynthesis. There was also improved shifting of antioxidant enzyme activities in the ASC/GSH and catalytic pathways in plants in response to OMW + AMF and Sb contamination, remarkably reducing oxidative damage markers. Conclusions: While individual applications of OMW and AMF also demonstrated some degree of plant tolerance induction, the combined presence of AMF with OMW supplementation significantly enhanced plant biomass production and adaptability to oxidative stress induced by soil Sb contamination. [ABSTRACT FROM AUTHOR]

Background: Saccharum spontaneumL. is a closely related species of sugarcane and has become an important genetic component of modern sugarcane cultivars. Stem development is one of the important factors for affecting the yield, while the molecular mechanism of stem development remains poorly understanding in S. spontaneum. Phenylalanine ammonia-lyase (PAL) is a vital component of both primary and secondary metabolism, contributing significantly to plant growth, development and stress defense. However, the current knowledge about PAL genes in S. spontaneum is still limited. Thus, identification and characterization of the PAL genes by transcriptome analysis will provide a theoretical basis for further investigation of the function of PAL gene in sugarcane. Results: In this study, 42 of PAL genes were identified, including 26 SsPAL genes from S. spontaneum, 8 ShPAL genes from sugarcane cultivar R570, and 8 SbPAL genes from sorghum. Phylogenetic analysis showed that SsPAL genes were divided into three groups, potentially influenced by long-term natural selection. Notably, 20 SsPAL genes were existed on chromosomes 4 and 5, indicating that they are highly conserved in S. spontaneum. This conservation is likely a result of the prevalence of whole-genome replications within this gene family. The upstream sequence of PAL genes were found to contain conserved cis-acting elements such as G-box and SP1, GT1-motif and CAT-box, which collectively regulate the growth and development of S. spontaneum. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that SsPAL genes of stem had a significantly upregulated than that of leaves, suggesting that they may promote the stem growth and development, particularly in the + 6 stem (The sixth cane stalk from the top to down) during the growth stage. Conclusions: The results of this study revealed the molecular characteristics of SsPAL genes and indicated that they may play a vital role in stem growth and development of S. spontaneum. Altogether, our findings will promote the understanding of the molecular mechanism of S. spontaneum stem development, and also contribute to the sugarcane genetic improving. [ABSTRACT FROM AUTHOR]

The plant growth regulator gibberellic acid (GA) and the herbicide glyphosate were examined for their possible interactions with growth and phenolic metabolism in soybean [Glycine max (L.) Merr. Cv. Hill] seedlings. GA caused increases in phenylalanine ammonia-lyase activity (PAL) (per axis basis) above those of the control seedling levels 48 h after treatment in light-grown seedlings. This effect increased to two-fold greater than control levels by 72 and 96 h after treatment. In dark-grown plants, GA had no effect on PAL levels at 24 h, reduced levels at 48 and 72 h, and increased PAL at 96 h. Early studies in our lab reported that glyphosate increased PAL levels, and also reduced hydroxyphenolic compound accumulation in both light- and dark-grown soybean seedlings. Treatments of GA plus glyphosate caused additive increases in PAL activity in light-grown seedlings, but GA lowered glyphosate's increase in PAL levels at 48–96 h after treatment in dark-grown seedlings. GA had little effect on hydroxyphenolic compound levels in either light- or dark-grown seedlings. GA treatment alone did not significantly affect root elongation, but stimulated hypocotyl and epicotyl elongation and caused marginal reversal of glyphosate inhibition of elongation in roots, hypocotyls, and epicotyls in light-grown plants. These results show some differential effects of GA and glyphosate on growth and phenolic metabolism, and their interactions that are dependent on plants grown in light or darkness. [ABSTRACT FROM AUTHOR]

Common sage (Salvia officinalis) is a perennial herb whose health-promoting value greatly depends on its phenolic compounds content. He–Ne laser and H2O2 are considered as potent elicitors to modulate secondary metabolism and stress tolerance in plants but their combined effect is unknown. Therefore, in the current study, we assessed the impact of solo and hybrid priming of seeds with H2O2 (5 mM) and He–Ne laser (6 J/cm2) on the composition of phenolics in S. officinalis under non-saline and saline conditions. Results revealed that salinity (75 mM NaCl) reduced biomass, the content of chlorophyll a, b, and carotenoids, increased electrolyte leakage, enhanced the total phenolic and flavonoid contents, and changed the proportion of phenolic fractions in leaves. Hybrid priming more prominently than individual seed priming with laser and H2O2 improved biomass and content of photosynthetic pigments, reduced electrolyte leakage, up-regulated phenylalanine ammonia-lyase (PAL) transcripts and activity of PAL enzyme, and intensified de novo biosynthesis of phenolic acids and flavonoids. Besides, HPLC analysis showed that hybrid priming further increased the content of ferulic, hesperidin, quercetin, kaempferol, luteolin, apigenin, and particularly rosmarinic acid and more strongly amplified DPPH scavenging capacity in leaves of salt-stressed plants. Overall, our results, via a heat map and principal component analysis, uncovered that hybrid priming with laser and H2O2 improved the salt tolerance and antioxidant value of S. officinalis. Therefore, hybrid priming might be a novel strategy to enhance the antioxidant properties and stress tolerance in medicinal plants. [ABSTRACT FROM AUTHOR]

The current study aimed to evaluate the impact of putrescine foliar application and inoculation with arbuscular mycorrhizal fungi on some growth characteristics, absorption of nutrients, and post-harvest performance of Gerbera jamesonii cv. Dune. The present study was performed as a factorial trial with a completely randomized design and a total of three repetitions in the greenhouse. Experimental variants included 0, 1, 2, and 4 mM concentrations of putrescine as foliar spraying and mycorrhizal fungi, with and without mycorrhizal inoculation. The amount of mycorrhiza inoculation was 60 g per pot. Gerbera plants were transplanted into pots with or without mycorrhizal inoculation. Two weeks after the establishment of the plant and mycorrhizal fungus, foliar spraying of putrescine was performed every 15 days during a three-month period. In this experiment, morphological features such as fresh and dry weight of the root, pedicel length and diameter, the volume of the root, absorption of nutrients, including phosphorus, potassium, calcium, and nitrate, as well as post-harvest features, including relative fresh weight, solution absorption rate, and phenylalanine ammonia-lyase enzyme activity, underwent investigation. The findings demonstrated that putrescine, along with mycorrhizal fungi, had a positive effect on the growth characteristics of Gerbera, could increase nutrient absorption, and improve post-harvest indicators. Overall, these results indicated that 2 and 4 mM putrescine could positively affect growth and nutrient uptake indices, while 1 mM putrescine was more effective for post-harvest characteristics. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia-lyase (PAL) is an essential enzyme in the phenylpropanoid pathway, in which numerous aromatic intermediate metabolites play significant roles in plant growth, adaptation, and disease resistance. Cultivated peanuts are highly susceptible to Aspergillus flavus L. infection. Although PAL genes have been characterized in various major crops, no systematic studies have been conducted in cultivated peanuts, especially in response to A. flavus infection. In the present study, a systematic genome-wide analysis was conducted to identify PAL genes in the Arachis hypogaea L. genome. Ten AhPAL genes were distributed unevenly on nine A. hypogaea chromosomes. Based on phylogenetic analysis, the AhPAL proteins were classified into three groups. Structural and conserved motif analysis of PAL genes in A. hypogaea revealed that all peanut PAL genes contained one intron and ten motifs in the conserved domains. Furthermore, synteny analysis indicated that the ten AhPAL genes could be categorized into five pairs and that each AhPAL gene had a homologous gene in the wild-type peanut. Cis-element analysis revealed that the promoter region of the AhPAL gene family was rich in stress- and hormone-related elements. Expression analysis indicated that genes from Group I (AhPAL1 and AhPAL2), which had large number of ABRE, WUN, and ARE elements in the promoter, played a strong role in response to A. flavus stress. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia lyase (PAL) is the rate-limiting and pivotal enzyme of the general phenylpropanoid pathway, but few reports have been found on PAL genes in Pinus yunnanensis. In the present study, three PAL genes were cloned and identified from P. yunnanensis seedlings for the first time, namely, PyPAL-1, PyPAL-2, and PyPAL-3. Our results indicated that the open-reading frames of PyPAL genes were 2184, 2157, and 2385 bp. Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants. In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid, but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine to ρ-coumaric acid. Three PyPAL genes were expressed in different tissues in 1-year-old P. yunnanensis, and such genes had different expression patterns. This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P. yunnanensis. [ABSTRACT FROM AUTHOR]

Phenylalanine ammonia-lyase (PAL) acts as the rate-limiting enzyme for anthocyanin biosynthesis through the phenylpropanoid pathway, a crucial component of plant secondary metabolism. The PAL gene family plays a crucial role in plants’ defense and stress responses, but its in silico identification and expression analyses in Brassica oleracea under different abiotic stresses remain unexplored. In this study, nine BolPAL, seven BrPAL, four AtPAL, and seventeen BnPAL genes were obtained from the genomes of B. oleracea, Brassica rapa, Arabidopsis thaliana, and Brassica napus, respectively. Segmental duplication and purifying selection are the causes of the BolPAL gene’s amplification and evolution. The BolPAL genes with comparable intron–exon architectures and motifs were grouped together in the same clade. Three categories comprised the cis-regulatory elements: abiotic stressors, phytohormones, and light. According to the results of the qRT-PCR experiments, the majority of the BolPAL genes were expressed highly under MeJA, a low temperature, and a high temperature, and they were downregulated under ABA. Under white light (100 µmol m−2 s−1) with 50, 100, or 150 µmol m−2 s−1 far-red (FR), only a small number of the PAL genes were expressed at 50 and 100 µmol m−2 s−1 FR, while the majority of the PAL genes were slightly elevated at 150 µmol m−2 s−1 FR. This work offers a theoretical foundation for molecular breeding research to investigate the role of BolPAL genes and their role in anthocyanin biosynthesis.

Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) catalyzes the deamination of phenylalanine, which is the initial step in the biosynthesis of phenylpropanoids. It serves as a crucial enzyme that facilitates the transfer of carbon from primary to secondary metabolism in plants. Duckweed is regarded as a promising chassis plant in synthetic biology research and application, due to its being rich in secondary metabolites and other advantages. The genes encoding PAL in Spirodela polyrhiza (L.) Schleid, the giant duckweed, were investigated in this study. Three SpPAL genes (SpPAL1–SpPAL3) were identified and cloned. All of them were successfully expressed in E. coli, and their recombinant proteins all showed PAL activity. In addition, SpPAL1 and SpPAL2 proteins could also utilize tyrosine as substrate, although the activity was low. A qRT-PCR analysis demonstrated that the expression of SpPAL3 was most pronounced in young fronds. It was found that the expression of SpPAL1 and SpPAL3 was significantly induced by MeJA treatment. Overexpression of SpPAL3 in Lemna turionifera inhibited the growth of fronds and adventitious roots in the transgenic plants, indicating the importance of SpPAL3 in duckweed besides its involvement in the secondary metabolism.

The latest research has shown that chitosan acts as a growth stimulator and elicitor in plants, including resistance to biotic and abiotic factors. However, increasing concentrations could possibly make chitosan a source of stress for plants. In this study, we investigated the effect of low-molecular-weight chitosan hydrolysate on the root development of tomato (Solanum lycoperscum) cultivars Red Cherry, Lel, and Tytan. The growth rate change, together with total phenolic content, phenylalanine ammonia-lyase (PAL) activity, and gene expression, were studied in relation to tomatoes. High concentrations of chitosan negatively affect the growth of tomato seedlings and contribute to changes in the tropism of the seedling roots. After the addition of chitosan hydrolysate, the PAL activity and the total phenolic content decreased 24 h later. PAL is a key enzyme in the biosynthesis of many plant stress factors. An analysis of the tomato PAL gene family was carried out. The SlPAL gene expression in the seedlings of cv. Cherry increased 1.5 times after 48 h, while in cv. Lel, the expression stably decreased in the presence of chitosan. The obtained results are supposed to aid our understanding of the mechanisms underlying the effects of chitosan on plant development and further its successful application in agriculture as well as in research on plant stress. [ABSTRACT FROM AUTHOR]

Aim: We aim to find a simple agricultural waste processing method to improve soil water retention and soil enzymes vitality, control soil-borne pathogens, and enhance plant resistance against biotic stress. Methods: We extracted polysaccharides from different agricultural wastes. We tested the antimicrobial activity of the extracted polysaccharides on different soil-borne pathogens and the effect of the addition of these polysaccharides on the soil water status and soil enzymes. Besides this, we investigated the efficiency of the peanut shells polysaccharides in improving tomato growth and defense under Fusarium solani and Ralstonia solanacearum infection in a greenhouse study. Results: Results showed the efficiency of all extracted polysaccharides as antimicrobial agents against different soil-borne pathogens. In addition, all polysaccharides increased the soil water holding capacity by about 116% more than that in the non-treated soil and increased the water retention to reach about 30% after eight days, besides their positive role in improving the soil enzymes, which improves the soil health. The peanut shells polysaccharides, which are the best ones as antimicrobials and soil amendments, showed interesting improvements in tomato growth under normal and pathogen infection conditions. The polysaccharide treatment decreased the bacterial and fusarium wilt in tomato plants, and induced resistance mechanism through up-regulating secondary metabolism defense compounds defense enzymes such as phenylalanine ammonia-lyase, and antioxidant enzymes detoxify the oxidative stress markers. Conclusion: Polysaccharides from agricultural wastes can be a promising soil amendment to improve the soil properties and so improve plant growth and defense mechanism against pathogen infection. [ABSTRACT FROM AUTHOR]

Salinity is an outstanding barrier against the production of agricultural crops, especially in arid and semi-arid regions. Oregano (Origanum vulgare L.), a valuable herb of the Lamiaceae family, contains various types of biologically active constituents such as essential oils, tannins, resins, sterols, flavonoids, and phenolic glycosides. The present research was carried out to investigate the influence of salinity stress on some physiological and biochemical attributes and antioxidant responses in two oregano subspecies (ssp. vulgare and ssp. gracile). Salt treatments were applied using irrigation with different sodium chloride concentrations (0, 25, 50, and 100 mM NaCl). The results revealed a remarkable decline in relative water content (RWC) and photosynthetic pigments in both subspecies under NaCl stress. Total soluble sugars (TSS) decreased in plants exposed to severe salt stress (100 mM NaCl), whereas H2O2 production, electrolyte leakage (EL), malondialdehyde (MDA), and leaf proline contents increased in these plants compared to control plants. A positive relationship was found between H2O2 production with EL and MDA. Furthermore, salinity improved phenolic content, antioxidant capacity, and activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzymes. The highest total flavonoid content (TFC) was achieved at 50 mM NaCl salinity, which increased by 19.33% compared to control plants. A positive relationship between the activity of phenylalanine ammonia-lyase (PAL) and TPC and TFC was observed. Analysis of phenolic compounds by HPLC showed that the amounts of gallic acid, caffeic acid, chlorogenic acid, and quercetin in ssp. gracile and caffeic acid, cinnamic acid, and quercetin in ssp. vulgare significantly increased with increasing salinity stress. In general, the findings of this study demonstrated that oregano subspecies ameliorate salt-induced osmotic and oxidative damages through increasing proline accumulation, antioxidant enzymes activity, and secondary metabolites production. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effectiveness of essential oil extracted from celery (Apium graveolens) seeds (CSEO) for the control of powdery mildew of cucumber (Cucumis sativus) incited by Podosphaera fusca and to investigate the metabolic and genetic defense mechanisms triggered by the treatment with this essential oil in cucumber seedlings. The main compounds in the CSEO as determined by gas chromatography–mass spectrometry (GC-MS) analysis were d-limonene, 3-butyl phthalide, β-selinene, and mandelic acid. The treatment with CSEO led to an increase in the content of both chlorophyll and phenolic/flavonoid compounds in cucumber leaves. In greenhouse tests, the application of CSEO reduced by 60% the disease severity on leaves of cucumber plants and stimulated the activity of defense-related enzymes such as β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase. Moreover, treatment with CSEO induced overexpression of β-1,3-glucanase, chitinase, and phenylalanine ammonia-lyase genes. A highly significant correlation was found between the β-1,3-glucanase, chitinase, and phenylalanine ammonia-lyase enzymatic activities and the relative expression of the corresponding encoding genes in both inoculated and non-inoculated cucumber seedlings treated with the essential oil. Overall, this study showed that CSEO is a promising eco-friendly candidate fungicide that can be exploited to control cucumber powdery mildew. [ABSTRACT FROM AUTHOR]

This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines. [ABSTRACT FROM AUTHOR]

Plant-parasitic nematodes are devastating pests of most crops, and their management still encounters challenges. Unraveling the plant-nematode interactions can shed light on the pathogenesis and resistance mechanisms, particularly in the case of the southern root-knot nematode Meloidogyne incognita interactions with monocots such as barley (Hordeum vulgare), to manage them properly. In this research, plant growth characteristics (length and fresh/dry weight of shoot and root), nematode gall index, resistance index, and reproduction factor were studied in barley genotypes namely ‘Bahman’, ‘Jolgeh’, ‘Khatam’, ‘Reyhan’, ‘Yousef’, ‘Nik’, ‘Nimrouz’ and ‘Zarjow’ at 60 days post-inoculation (dpi). Afterwards, the activity of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and phenylalanine ammonia-lyase (PAL) enzymes were measured at 0, 1, 2, 3, 4, and 10 dpi. The results showed that all plant growth characteristics except for the root weight decreased upon inoculation. While genotypes ‘Reyhan’, ‘Nik’ and ‘Yousef’ were proved to be resistant, moderately susceptible and susceptible, respectively, the remaining genotypes exhibited a moderate resistance response. In the ‘Reyhan’ genotype, the SOD, CAT, APX and GPX enzymes peaked at 1 dpi, whereas in other genotypes they increased over time. The genotype ‘Reyhan’ was completely different from the others in terms of peak time (except for PAL). The early enzymatic activity was likely related to the timely response of the resistant genotype ‘Reyhan’ to the nematode, while the late activity probably affected the tolerance to the nematode in the other genotypes. PAL exhibited an upward slope in the more resistant genotypes and probably had a positive correlation with resistance. [ABSTRACT FROM AUTHOR]

Sparganium stoloniferum is a widely distributed aquatic medicinal plant that exhibits exceptional tolerance to environmental stress. Interestingly, the phenols in S. stoloniferum which have medicinal properties, are defensive compounds. Studies integrating transcriptome, proteome, and metabolome analyses have highlighted the phenylpropanoid and flavonoid biosynthesis pathways, which are related to the defense mechanisms of S. stoloniferum. During the growth process, S. stoloniferum rhizoma (SL) accumulates lignin, forming a physical defense, and phenylpropanoids and flavonoids derived during the lignin biosynthesis process provide chemical defense. In this study, a map of the molecular processes involved in the coordinated defense of S. stoloniferum was generated. The expression patterns of genes involved in the coordinated defense of SL were consistent with the omics results. The cDNA of the phenylalanine ammonia-lyase (PAL) gene from S. stoloniferum (SsPAL) was cloned. The recombinant protein SsPAL showed good affinity and catalytic activity for L-phenylalanine. Heat stress experiments indicated that genes related to phenol biosynthesis were upregulated when S. stoloniferum responded to stress. Therefore, phenols played a crucial defense role when S. stoloniferum was at an early developmental stage or responded to stress in a short time. In contrast, the physical defense mainly relied on lignin formation, which was the main defense mechanism of SL in the late growth stage. Based on these results, we discuss the causes of phenolic pharmacological substance formation in medicinal aquatic plants. These results provide new insights into the defense strategies of aquatic plants.

The PAL gene family plays an important role in plant growth, development, and response to abiotic stresses and has been identified in a variety of plants. However, a systematic characterization is still lacking in Ginkgo biloba. Using a bioinformatics approach, 11 GbPAL members of the PAL gene family identified in ginkgo were identified in this study. The protein structure and physicochemical properties indicated that the GbPAL genes were highly similar. Based on their exon-intron structures, they can be classified into three groups. A total of 62 cis-elements for hormone, light, and abiotic stress responses were identified in the promoters of GbPAL genes, indicating that PAL is a multifunctional gene family. GbPAL genes were specifically expressed in different tissues and ploidy of ginkgo. These results provide a theoretical basis for further studies on the functional expression of the GbPAL genes.

In this research, we investigated the impact of drought stress on secondary metabolite production in cumin plants and the associated transcriptional changes in biosynthetic genes. Drought stress induced a significant increase in the levels of beta-carotene, lycopene, terpenes, anthocyanin, phenolic compounds, flavonoids, and alkaloids, indicating an adaptive metabolic shift in response to adverse conditions. Concurrently, there was an upregulation in the expression of key biosynthetic genes, including Phenylalanine ammonia-lyase (PAL), 3-deoxy-7-phosphoheptulonate synthase (DAHP synthase), Deoxy xylose phosphate reductase (DXS), 3‑hydroxy-3-methylglutaryl-CoA reductase (HMGR), and Geranyl diphosphate synthase (GPPS), which corroborated the metabolite findings. Notably, while most secondary metabolites exhibited an increasing trend under drought stress, flavonoids displayed a disproportionate elevation, even as there was an overall decrease in phenolic compounds and other metabolites. This observation suggests the potential activation of alternative flavonoid synthesis pathways or the conversion of phenolic compounds to flavonoids during stress. Strong correlations were identified between the expression of biosynthetic genes and their respective metabolite concentrations, underscoring the central role of transcriptional regulation in secondary metabolite synthesis during drought stress. Collectively, our results provide a comprehensive understanding of the transcriptional and metabolic adaptations of cumin plants when exposed to drought stress. Such insights can be pivotal in designing drought-resilient crops, with significant implications for food security amidst escalating climatic challenges.

In this study we assessed the applicability of the recently reported ancestral l -amino acid oxidase (AncLAAO), for the development of an enzyme-coupled phenylalanine ammonia-lyase (PAL) activity assay. Firstly, the expression and isolation of the AncLAAO-N1 was optimized, followed by activity tests of the obtained octameric N-terminal His-tagged enzyme towards various phenylalanine analogues to assess the compatibility of its substrate scope with that of the well-characterized PALs. AncLAAO-N1 showed high catalytic efficiency towards phenylalanines mono-, di-, or multiple-substituted in the meta- or para- positions, with ortho- substituted substrates being poorly transformed, these results highlighting the significant overlap between its substrate scope and those of PALs. After successful set-up of the AncLAAO-PAL coupled solid phase assay, in a 'proof of concept' approach we demonstrated its applicability for the high-throughput activity screens of PAL-libraries, by screening the saturation mutagenesis-derived I460NNK variant library of PAL from Petroselinum crispum , using p -MeO-phenylalanine as model substrate. Notably, the hits revealed by the coupled assay comprised all the active PAL variants: I460V, I460T, I460S, I460L, previously identified from the tested PAL-library by other assays. Our results validate the applicability of AncLAAO for coupled enzyme systems with phenylalanine ammonia-lyases, including cell-based assays suitable for the high-throughput screening of directed evolution-derived PAL-libraries. • Substrate scope of ancestral L -amino acid oxidases extends to various phenylalanines. • AncLAAO and phenylalanine ammonia-lyases (PALs) share overlapping substrate domains. • High-throughput, AncLAAO-coupled, solid-phase PAL-activity assay was developed • Screening efficiency of the assay validated on engineered PAL variant library. [ABSTRACT FROM AUTHOR]

Cassava (Manihot esculenta Crantz) is a food and industrial storage root crop with substantial potential to contribute to managing risk associated with climate change due to its inherent resilience and in providing a biodegradable option in manufacturing. In Africa, cassava production is challenged by two viral diseases, cassava brown streak disease (CBSD) and cassava mosaic disease. Here we detect quantitative trait loci (QTL) associated with CBSD in a biparental mapping population of a Tanzanian landrace, Nachinyaya and AR37-80, phenotyped in two locations over three years. The purpose was to use the information to ultimately facilitate either marker-assisted selection or adjust weightings in genomic selection to increase the efficiency of breeding. Results from this study were considered in relation to those from four other biparental populations, of similar genetic backgrounds, that were phenotyped and genotyped simultaneously. Further, we investigated the co-localization of QTL for CBSD resistance across populations and the genetic relationships of parents based on whole genome sequence information. Two QTL on chromosome 4 for resistance to CBSD foliar symptoms and one on each of chromosomes 11 and 18 for root necrosis were of interest. Of significance within the candidate genes underlying the QTL on chromosome 4 are Phenylalanine ammonia-lyase (PAL) and Cinnamoyl-CoA reductase (CCR) genes and three PEPR1-related kinases associated with the lignin pathway. In addition, a CCR gene was also underlying the root necrosis-resistant QTL on chromosome 11. Upregulation of key genes in the cassava lignification pathway from an earlier transcriptome study, including PAL and CCR, in a CBSD-resistant landrace compared to a susceptible landrace suggests a higher level of basal lignin deposition in the CBSD-resistant landrace. Earlier RNAscope® in situ hybridisation imaging experiments demonstrate that cassava brown streak virus (CBSV) is restricted to phloem vessels in CBSV-resistant varieties, and phloem unloading for replication in mesophyll cells is prevented. The results provide evidence for the involvement of the lignin pathway. In addition, five eukaryotic initiation factor (eIF) genes associated with plant virus resistance were found within the priority QTL regions. [ABSTRACT FROM AUTHOR]

Changes occurring in seeds of two field bean cultivars during long-term storage at −14 °C, +4 °C and +20 °C were examined. It was found that after 33 years of storage at low temperatures, the seeds showed a significant decline in biological quality, and the seeds stored at +20 °C completely lost their germination capacity. As the seeds aged, changes in their phenolic composition, concentrations of polyamines and activity of enzymes associated with redox homeostasis and phenolic metabolism could be easily observed. The activity of ascorbate peroxidase and phenylalanine ammonia-lyase in deteriorated seeds was higher than in high-quality seeds. The activity of guaiacol peroxidase, catalase and glutathione reductase in low-quality seeds was decreased. With superoxide dismutase, the pattern was less clear-cut and depended on both seed biological quality and cultivar. Whole seed levels of spermine and spermidine decreased in ageing seeds and were lowest in non-germinating seeds. However, the opposite pattern was observed regarding spermine and spermidine, as well as putrescine, in seed coats. The obtained results indicate that changes in the activity of redox and protective systems in seeds have a clear relationship with the seed biological quality and can be detected even at a moderate level of seed deterioration. The analyses of such changes can significantly facilitate the assessment of seed quality and can therefore be of interest for seed companies and seed banks. [ABSTRACT FROM AUTHOR]

【Objective】This study aimed to explore the correlation between the content of imperatorin and the expression of the phenylalanine ammonia-lyase gene (AdPAL1) of Angelica dahurica cv. Yubaizhi (YBZ). In addition, AdPAL1 was cloned and expressed in prokaryotes.【Method】The content of imperatorin in the roots and leaves of YBZ during its rapid growth stage and harvest stages was measured using high-performance liquid chromatography (HPLC), and the expression of the AdPAL1 gene in the roots and leaves during the same stages was detected using real-time fluorescent quantitative PCR (qRT-PCR) to observe whether there was a correlation between imperatorin content and the expression of the AdPAL1 gene. Furthermore, the AdPAL1 gene was cloned from the root of YBZ based on its transcriptome using reverse transcription-polymerase chain reaction (RT-PCR) technology, and it was expressed in Escherichia coli.【Result】During the rapid growth period of YBZ, the content of imperatorin in the roots is much higher than that in the leaves, and the expression level of AdPAL1 in the roots is also much higher than that in the leaves. Compared with the rapid growth stage, the content of imperatorin in the roots slightly decreases during the har vest stag e, and the expression level of AdPAL1 gene in the roots also decreases at the same time. These results indicate a correlation between the expression of AdPAL1 gene and the content of imperatorin. In addition, bioinformatics analysis show that the AdPAL1 gene (GenBank accession number: OQ822236) of YBZ has an open reading frame length of 1 764 bp and encods 557 amino acids. The relative molecular weight of AdPAL1 protein is 61.10 kD, and its isoelectric point is 5.92. It has a conserved domain of phenylalanine ammonia lyase (IPR005922, 1-547), which belongs to the PAL protein family and it is located in the cytoplasm and is mainly composed of α- helixes and irregular coils. AdPAL1 has the closest genetic relationship with the KpPAL2 protein in Kitagawia praeruptora, with a local sequence similarity of up to 99.28%. The relative molecular weight of the recombinant protein of AdPAL1 gene expressed in E. coli is about 84.00 kD, which is consistent with the expected protein size.【Conclusion】The correlation between the content of imperatorin in roots and leaves of YBZ and the expression of AdPAL1 gene was preliminarily determined, and the AdPAL1 gene was cloned and successfully expressed in E. coli. These results provide a reference for further research on the mechanism of AdPAL1 gene in imperatorin biosynthesis.

Abstract Background Fusarium crown rot (FCR) is a chronic disease of cereals worldwide. Compared with tetraploid wheat, hexaploid wheat is more resistant to FCR infection. The underlying reasons for the differences are still not clear. In this study, we compared FCR responses of 10 synthetic hexaploid wheats (SHWs) and their tetraploid and diploid parents. We then performed transcriptome analysis to uncover the molecular mechanism of FCR on these SHWs and their parents. Results We observed higher levels of FCR resistance in the SHWs compared with their tetraploid parents. The transcriptome analysis suggested that multiple defense pathways responsive to FCR infection were upregulated in the SHWs. Notably, phenylalanine ammonia lyase (PAL) genes, involved in lignin and salicylic acid (SA) biosynthesis, exhibited a higher level of expression to FCR infection in the SHWs. Physiological and biochemical analysis validated that PAL activity and SA and lignin contents of the stem bases were higher in SHWs than in their tetraploid parents. Conclusion Overall, these findings imply that improved FCR resistance in SHWs compared with their tetraploid parents is probably related to higher levels of response on PAL-mediated lignin and SA biosynthesis pathways.

The plant growth regulator gibberellic acid (GA) and the herbicide glyphosate were examined for their possible interactions with growth and phenolic metabolism in soybean [Glycine max (L.) Merr. Cv. Hill] seedlings. GA caused increases in phenylalanine ammonia-lyase activity (PAL) (per axis basis) above those of the control seedling levels 48 h after treatment in light-grown seedlings. This effect increased to two-fold greater than control levels by 72 and 96 h after treatment. In dark-grown plants, GA had no effect on PAL levels at 24 h, reduced levels at 48 and 72 h, and increased PAL at 96 h. Early studies in our lab reported that glyphosate increased PAL levels, and also reduced hydroxyphenolic compound accumulation in both light- and dark-grown soybean seedlings. Treatments of GA plus glyphosate caused additive increases in PAL activity in light-grown seedlings, but GA lowered glyphosate’s increase in PAL levels at 48–96 h after treatment in dark-grown seedlings. GA had little effect on hydroxyphenolic compound levels in either light- or dark-grown seedlings. GA treatment alone did not significantly affect root elongation, but stimulated hypocotyl and epicotyl elongation and caused marginal reversal of glyphosate inhibition of elongation in roots, hypocotyls, and epicotyls in light-grown plants. These results show some differential effects of GA and glyphosate on growth and phenolic metabolism, and their interactions that are dependent on plants grown in light or darkness.

Cassava (Manihot esculenta Crantz) is a food and industrial storage root crop with substantial potential to contribute to managing risk associated with climate change due to its inherent resilience and in providing a biodegradable option in manufacturing. In Africa, cassava production is challenged by two viral diseases, cassava brown streak disease (CBSD) and cassava mosaic disease. Here we detect quantitative trait loci (QTL) associated with CBSD in a biparental mapping population of a Tanzanian landrace, Nachinyaya and AR37-80, phenotyped in two locations over three years. The purpose was to use the information to ultimately facilitate either marker-assisted selection or adjust weightings in genomic selection to increase the efficiency of breeding. Results from this study were considered in relation to those from four other biparental populations, of similar genetic backgrounds, that were phenotyped and genotyped simultaneously. Further, we investigated the co-localization of QTL for CBSD resistance across populations and the genetic relationships of parents based on whole genome sequence information. Two QTL on chromosome 4 for resistance to CBSD foliar symptoms and one on each of chromosomes 11 and 18 for root necrosis were of interest. Of significance within the candidate genes underlying the QTL on chromosome 4 are Phenylalanine ammonia-lyase (PAL) and Cinnamoyl-CoA reductase (CCR) genes and three PEPR1-related kinases associated with the lignin pathway. In addition, a CCR gene was also underlying the root necrosis-resistant QTL on chromosome 11. Upregulation of key genes in the cassava lignification pathway from an earlier transcriptome study, including PAL and CCR, in a CBSD-resistant landrace compared to a susceptible landrace suggests a higher level of basal lignin deposition in the CBSD-resistant landrace. Earlier RNAscope®in situ hybridisation imaging experiments demonstrate that cassava brown streak virus (CBSV) is restricted to phloem vessels in CBSV-resistant varieties, and phloem unloading for replication in mesophyll cells is prevented. The results provide evidence for the involvement of the lignin pathway. In addition, five eukaryotic initiation factor (eIF) genes associated with plant virus resistance were found within the priority QTL regions.

Fallopia multiflora (Thunb.) Harald. is a commonly used traditional Chinese medicine that is rich in chemical constituents. Phenylalanine ammonia-lyase (PAL) is the first key enzyme in the phenylalanine pathway, catalyzing the deamination of L-phenylalanine to generate trans-cinnamic acid. Three PALs (FmPAL1, FmPAL2, and FmPAL3) were cloned and validated from F. multiflora for the first time, demonstrated the presence of a multigene family of PALs in F. multiflora. The predicted complete open reading frames (ORFs) of FmPAL1, FmPAL2, and FmPAL3 are 2118bp, 2109bp and 2160bp, encoding 705, 702 and 719 amino acids, respectively. The phylogenetic results indicated that FmPALs have significant evolutionary relatedness with the known PALs from dicotyledons. To further confirm their function, the three FmPALs were cloned into the pET-28a vector and expressed in Escherichia coli TransBL21 (DE3). The enzymatic activities of the FmPALs recombinant proteins were assayed and showed that FmPALs have a role in the d-catalyzed conversion of L-phenylalanine to trans-cinnamic acid. All three FmPALs showed tissue-specific expression. The expression of FmPAL1 and FmPAL2 genes were highest in stems and lowest in roots. Differently, the expression of FmPAL3 gene was highest in leaves and lowest in roots. [ABSTRACT FROM AUTHOR]

CIM-Saumya is an improved, methyl chavicol rich variety of Ocimum basilicum (Family—Lamiaceae), developed by Council of Scientific and Industrial Research-Central Institute of Medicinal and Aromatic Plants. This plant possesses analgesic, anti-ulcerogenic, anti-inflammatory, anti-oxidant, cardiac stimulant, Central Nervous System depressant, hepatoprotective and immunomodulator activities due to the presence of various phytoconstituents. Among them rosmarinic acid, caffeic acid and ferulic acid are the three major phenolic compounds responsible for its therapeutic utility. These compounds are produced in very low amounts in the in vivo plants. Therefore, the present study has been conducted for establishment of cell suspensions, optimization of inoculums size, growth kinetics and screening of elicitor and precursors for the accumulation of cell biomass and the production of the three important phenolic compounds in cell suspension of O. basilicum (CIM-Saumya). Leaf derived friable callus was used for establishing the cell suspension in liquid Murashige and Skoog's medium fortified with 1 g/L casein hydrolysate + 2.26 µM 2,4-dichlorophenoxyacetic acid + 0.465 µM kinetin + 2.68 µM naphthalene acetic acid. The growth kinetic analysis pattern of cell suspension revealed the maximum biomass increments (% BI = 486.7) and production of RA 8.086 mg/g dry weight was found in 30th day harvested cells. Whereas, the other two phenolic compounds i.e. ferulic acid (0.0125 mg/g dry weight) and caffeic acid (0.38 mg/g dry weight) was recorded highest on 25th day of growth cycle. In the present study, one biotic elicitor i.e. yeast extract and three precursors [peptone, tryptone and lactalbumin hydrolysate] were tested, among them, lactalbumin hydrolysate (100 mg/L; added at 16th day) treated cells recorded highest estimated phenolic compounds yield (251.5 mg/L; 6.81 fold compared to the control) and biomass increments i.e. % BI = 1207 with 1.85 fold compared to the control. The highest rosmarinic acid content i.e. 25.47 mg/g DW (4.4 fold compared to the control) and 24.42 mg/g dry weight (4.1 folds compared to the control) was noticed in 30th day harvested cells treated with yeast extract (1 g/L on 0 day) and lactalbumin hydrolysate (100 mg/L added on 16th day), respectively. While caffeic acid content (0.91 mg/g dry weight) showed 2.9 folds higher compared to the control in cells treated with peptone 200 mg/L added on 16th day of culture cycle. All the treated cells showed enhanced phenylalanine ammonia-lyase enzyme activity with highest specific activity in lactalbumin hydrolysate followed by tryptone, peptone, and yeast extract. [ABSTRACT FROM AUTHOR]

Background: Fusarium crown rot (FCR) is a chronic disease of cereals worldwide. Compared with tetraploid wheat, hexaploid wheat is more resistant to FCR infection. The underlying reasons for the differences are still not clear. In this study, we compared FCR responses of 10 synthetic hexaploid wheats (SHWs) and their tetraploid and diploid parents. We then performed transcriptome analysis to uncover the molecular mechanism of FCR on these SHWs and their parents. Results: We observed higher levels of FCR resistance in the SHWs compared with their tetraploid parents. The transcriptome analysis suggested that multiple defense pathways responsive to FCR infection were upregulated in the SHWs. Notably, phenylalanine ammonia lyase (PAL) genes, involved in lignin and salicylic acid (SA) biosynthesis, exhibited a higher level of expression to FCR infection in the SHWs. Physiological and biochemical analysis validated that PAL activity and SA and lignin contents of the stem bases were higher in SHWs than in their tetraploid parents. Conclusion: Overall, these findings imply that improved FCR resistance in SHWs compared with their tetraploid parents is probably related to higher levels of response on PAL-mediated lignin and SA biosynthesis pathways. [ABSTRACT FROM AUTHOR]

Intercropping is a tried-and-true approach for restoring depleted agricultural soils, making better use of resources, controlling pests and disease, and ultimately boosting crop yield by reducing soil disease. This study tries to evaluate the role of tomato potato onion intercropping in induction tomato resistance against the soil-borne pathogen, Fusarium oxysporum. The study included four treatments Tomato seedlings monoculture in non-infected soil, Tomato seedlings monoculture in Fusarium infected soil, Tomato/potato onion intercropping in non-infected soil, Tomato/potato onion intercropping in Fusarium infected soil. Roots and shoots of tomato plants and soil were collected at 2 and 4 weeks after transplanting. Results showed that tomato/potato onion intercropping can enhance tomato resistance against Fusarium wilt. This is achieved through the improvement of soil enzymes and antifungal enzyme activity in the soil which release compounds from the Fusarium cell wall hydrolysis which act as elicitors to initiate defense response in the tomato plants. The defense response is represented in the elevation of the antioxidant capacity and enzymes which antagonize the oxidative stress. Additionally, as a result of the defense response, the secondary metabolism has improved, as evidenced by increased activity in the phenylalanine ammonia-lyase and consumption of the shikimic acid, which raises the amounts of phenols and flavonoids. Besides that, the intercropped tomato showed high activity in the antifungal enzymes and high content of cell wall-bound phenols which stop the fungal growth spread inside tomato plants. [ABSTRACT FROM AUTHOR]

BACKGROUND: The chemical composition, phenylalanine ammonia‐lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) activity of the three main Portuguese elderberry cultivars were determined for the first time through five stages of maturation, in different harvesting years, to gain a deeper understanding of the effect of climatic conditions and enzymatic activity involved in the synthesis and degradation of phenolic compounds on the final quality of elderberries. RESULTS: Simple sugar and anthocyanin content increased with maturation but total acidity and flavonoids content decreased, and cinnamic acids did not show a clear trend. Climatic conditions seem to have a decisive influence on the elderberry maturation, namely the total number of hot (>30 °C) days. The PAL, PPO, and POD activity can explain the differences observed in elderberry phenolic content. CONCLUSION: These results highlighted the influence of climatic conditions in each harvesting season on elderberry development and quality. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In nature; Flammulina velutipes, also known as winter mushrooms, vary in the color of their fruiting bodies, from black, yellow, pale yellow, or beige to white. The purpose of this study was to compare the genome sequences of different colored strains of F. velutipes and to identify variations in the genes associated with fruiting body color. Comparative genomics of six F. velutipes strains revealed 70 white-strain-specific variations, including single nucleotide polymorphisms (SNPs) and insertions/deletions (indels), in the genome sequences. Among them, 36 variations were located in the open reading frames, and only one variation was identified as a mutation with a disruptive in-frame deletion (ΔGCGCAC) within the annotated gene phenylalanine ammonia-lyase 1 (Fvpal1). This mutation was found to cause a deletion, without a frameshift, of two amino acids at positions 112 and 113 (arginine and threonine, respectively) in the Fvpal1 gene of the white strain. Specific primers to detect this mutation were designed, and amplification refractory mutation system (ARMS) polymerase chain reaction (PCR) was performed to evaluate whether the mutation is color specific for the F. velutipes fruiting body. PCR analysis of a total of 95 F. velutipes strains revealed that this mutation was present only in white strains. In addition, monospores of the heterozygous mutant were isolated, and whether this mutation was related to the color of the fruiting body was evaluated by a mating assay. In the mating analysis of monospores with mutations in Fvpal1, it was found that this mutation plays an important role in determining the color of the fruiting body. Furthermore, the deletion (Δ112RT113) in Fvpal1 is located between motifs that play a key role in the catalytic function of FvPAL1. These results suggest that this mutation can be used as an effective marker for the color-specific breeding of F. velutipes, a representative edible mushroom. [ABSTRACT FROM AUTHOR]

Secondary metabolites have been shown to possess a range of biological functions. Flavonoids, due to their ability to scavenge ROS, are famous antioxidants. The plants of Artemisia species are rich sources of flavonoids; however, the amount of these metabolites is less. In the current study, the flavonoid content was detected and then enhanced by genetically modifying the Artemisia carvifolia Buch with Agrobacterium tumefaciens strain GV3101 carrying rol A gene. The transformation of rol A gene was confirmed with PCR and the gene copy number was confirmed by Southern blot analysis. The HPLC analysis revealed the presence of catechin (3.19 ug/mg DW) and geutisic acid (2.22 ug/mg DW) in transformed plants, unlike wild-type plants. In transformed plants, all detected flavonoids (vanillic acid, rutin, catechine, gallic acid, syringic acid, caffeic acid, coumaric acid, geutisic acid, ferulic acid, and cinnamic acid) were increased up to several folds. Real-time qPCR revealed the higher expression levels of the genes for flavonoid biosynthesis enzymes phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) in plants transformed with rol A genes, as the expression levels were increased up to 9–20-fold and 2–6-fold, respectively. The rol A transgenic lines T3 and T5 carrying two copies of rol A gene, particularly showed higher expression of both PAL and CHS gene, with the highest expression in T3 line. The transgenic lines demonstrated an average increase of 1.4-fold in the total phenolic content and 1–2-fold in the total flavonoid content as compared to wild-type plants. Total antioxidant capacity and total reducing power were increased up to an average of 1–2-fold and 1.5–2-fold respectively, along with increased free radical scavenging ability. Furthermore, the rol A gene transgenics were found to have much greater cytotoxic capacity than the A. carvifolia wild-type plant against the MCF7, HeLA, and HePG2 cancer cell lines. Current findings show that the rol A gene effectively increases the flavonoid content of A. carvifolia Buch, boosting the plant's capacity as an antioxidant and an anticancer. This is the first-ever report, demonstrating the genetic transformation of Artemisia carvifolia Buch with rol A gene. [ABSTRACT FROM AUTHOR]

Phenylketonuria is an inborn error of phenylalanine metabolism caused by a phenylalanine hydroxylase deficiency. To prevent the occurrence of neurological symptoms and maternal complications resulting from phenylketonuria, patients must adhere to a strict diet therapy, tetrahydrobiopterin supplementation, or pegvaliase injection to maintain blood phenylalanine levels within a recommended range throughout their lives. Therefore, monitoring blood phenylalanine levels is necessary to determine the recent metabolic status of phenylalanine in patients with PKU; however, there are no available instruments for individuals to monitor their own blood phenylalanine levels using whole fingertip blood. We developed a phenylalanine monitoring system (designated as PheCheck) that included a pre-existing portable ammonia detection device and phenylalanine ammonia-lyase, which converts phenylalanine to trans-cinnamic acid and ammonia. This system was able to remove 86.7% ± 0.03% of the ammonia contained in fingertip blood and successfully reduce background ammonia levels. A good correlation was found between the estimated plasma phenylalanine levels detected by PheCheck and plasma phenylalanine levels detected by high-performance liquid chromatography (R2 0.97). The entire PheCheck process for measuring blood phenylalanine takes only 20 min. PheCheck can lay the foundation for home phenylalanine monitoring with high feasibility because all the components are easily accessible. Further studies with a more user-friendly PheCheck optimized for practice are needed to improve blood phenylalanine control, reduce the burden on patients and/or caregivers, and prevent the sequelae associated with phenylketonuria.

The latest research has shown that chitosan acts as a growth stimulator and elicitor in plants, including resistance to biotic and abiotic factors. However, increasing concentrations could possibly make chitosan a source of stress for plants. In this study, we investigated the effect of low-molecular-weight chitosan hydrolysate on the root development of tomato (Solanum lycoperscum) cultivars Red Cherry, Lel, and Tytan. The growth rate change, together with total phenolic content, phenylalanine ammonia-lyase (PAL) activity, and gene expression, were studied in relation to tomatoes. High concentrations of chitosan negatively affect the growth of tomato seedlings and contribute to changes in the tropism of the seedling roots. After the addition of chitosan hydrolysate, the PAL activity and the total phenolic content decreased 24 h later. PAL is a key enzyme in the biosynthesis of many plant stress factors. An analysis of the tomato PAL gene family was carried out. The SlPAL gene expression in the seedlings of cv. Cherry increased 1.5 times after 48 h, while in cv. Lel, the expression stably decreased in the presence of chitosan. The obtained results are supposed to aid our understanding of the mechanisms underlying the effects of chitosan on plant development and further its successful application in agriculture as well as in research on plant stress.

This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines.

Aspartate ammonia-lyase (AAL) catalyzes the reversible conversion reactions of aspartate to fumaric acid and ammonia. In this work, Lactobacillus paracasei LpAAL gene was heterologously expressed in Escherichia coli. As well as a recombinant His-tagged LpAAL protein, a maltose-binding protein (MBP) fused LpAAL protein was used to enhance its protein solubility and expression level. Both recombinant proteins showed broad substrate specificity, catalyzing aspartic acid, fumaric acid, phenylalanine, and tyrosine to produce fumaric acid, aspartic acid, trans-cinnamic acid, and p-coumaric acid, respectively. The optimum reaction pH and temperature of LpAAL protein for four substrates were measured at 8.0 and 40 °C, respectively. The Km values of LpAAL protein for aspartic acid, fumaric acid, phenylalanine, and tyrosine as substrates were 5.7, 8.5, 4.4, and 1.2 mM, respectively. The kcat values of LpAAL protein for aspartic acid, fumaric acid, phenylalanine, and tyrosine as substrates were 6.7, 0.45, 4.96, and 0.02 s−1, respectively. Therefore, aspartic acid, fumaric acid, phenylalanine, and tyrosine are bona fide substrates for LpAAL enzyme. [ABSTRACT FROM AUTHOR]

Brassica species, capable of heavy metals (HMs) hyperaccumulation, differ in their ability to accumulate and tolerate metals present in their environment. In this comparative study, the accumulation, morphological, and physiological responses of three Brassica species i.e., Brassica juncea, B. napus, and B. campestris, against lead (Pb) were examined. Plants were grown in pots under greenhouse conditions and subjected to 0, 50, 100, 150 mM concentrations of Pb for 14 days. The study revealed that 150 mM Pb concentration reduced the plant length and biomass in all the species and this decline was more obvious in B. napus. At 100 mM Pb concentration, plant length increased 3.5% in B. juncea, while decreased by 8 and 36% in B. campestris and B. napus, respectively. B. campestris and B. napus suffered from more pronounced Pb-accumulation in the root followed by shoot as compared to B. juncea. Pb-accumulation in 100 mM treated root of B. campestris and B. napus increased 29 and 80%, respectively as compared to B. juncea Pb treated root. Antioxidant enzyme catalase (CAT) activity was increased in B. juncea and B. campestris up to 150 mM concentration, while in B. napus activity of enzyme decreased at 100 and 150 mM Pb concentration. Phenylalanine ammonia-lyase (PAL) and nitrate reductase activity increased at 50 mM, while the polyphenol oxidase (PPO) and nitrite reductase significantly increased at 150 mM. Brassica species also showed more significant accumulation of amino acid, inhibition of proteins and total sugar content at 100 and 150 mM concentrations. Although all species exhibited enhanced antioxidant activity, activation in B. juncea was relatively higher. These results suggest that B. juncea is relatively more tolerant towards Pb stress as compared to B. campestris and B. napus due to reduced metal uptake and enhanced antioxidant enzyme activities. [ABSTRACT FROM AUTHOR]