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Eucheuma denticulatum and Kappaphycus alvarezii are two of the most commercially important, cultivated carrageenophytes in Southeast Asia. Their large-scale farming through repeated vegetative propagation and virtual monocropping has resulted in a variety of phyconomic issues. The efficacy of two European, commercial liquid extracts from the brown seaweeds, i.e., Ascophyllum nodosum (ANE), a fucoid, and Laminaria digitata (LDE), a kelp, on the direct formation of axes and survival of these two eucheumatoids was examined using tissue culture techniques. Seaweed apical sections (2–3 mm long) were cultured for 45 days, with different concentrations of ANE and LDE (i.e., 0.005, 0.05, 0.5, 1.5, and 2.5 mL L−1) and compared with a control (UV-filtered seawater). Lower concentrations (< 1.5 mL L−1) of both liquid extracts promoted morphogenesis and growth of E. denticulatum and K. alvarezii in tissue culture, with the dilution rate of 0.05 mL LDE L−1 resulting in a high percentage survival (i.e., 95.3 ± 0.9%), formation of direct axes (i.e., 95.3 ± 0.9%), and the longest length (i.e., 10.0 ± 0.3 mm) for E. denticulatum after a typical 45-day culture period. A 0.5 mL ANE L−1 concentration was found to be beneficial for the tissue culture of K. alvarezii, given the relatively high final survival and direct axes formation (i.e., 96.2 ± 2.2%) and axes length (i.e., 8.2 ± 0.1 mm). This study supports the application of these temperate, brown seaweed-derived extracts as a phycobiostimulant enrichment in eucheumatoid micropropagation for mass production of plantlets for out-planting purposes. [ABSTRACT FROM AUTHOR]

Abiotic stress, especially drought, is one of the principal constraints of crop productivity and is expected to worsen with climate change in the near future. This warrants the development of new technologies to decrease the impact of drought on crop productivity. Biostimulants made from seaweed extracts are one of the relatively new biological based inputs that can help mitigate the negative effects of abiotic stress on plants by enhancing growth, development, and stress tolerance. The current study evaluated the impact of Ascophyllum nodosum extract (SWE) on tomato plants grown under different levels of water stress. Greenhouse studies were conducted to assess the effect of foliar spray (0.5%) of the extract on stomatal conductance, photosynthesis, chlorophyll content, and biomass, for plants grown at moisture levels of 100%, 50%, and 25% of field capacity. A field study was also conducted with irrigation maintained at 100% and 25% (irrigation capacity). Additionally, the expression levels of marker genes associated with drought tolerance were evaluated using qPCR studies for Metacaspase 1 (LeMCA1), Non-specific lipid-transfer protein 2 (Itpg2), Late embryogenesis abundant protein (LEA) and Delta 1-pyrroline-5- carboxylate synthetase (P5CS) genes. Assays were also conducted on plants for osmolyte content including proline and glycine betaine. Furthermore, the activities of antioxidant defense enzymes were evaluated for superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX). The results of the greenhouse study indicated higher stomatal conductance, chlorophyll content, and Fv/Fm in stressed plants that were foliar sprayed with the A. nodosum extract. Seaweed extract-treated plants under water-stress conditions also had significantly greater shoot and root dry weights compared to control plants. The relative expression levels of the marker genes were also significantly increased in SWE sprayed plants compared to control plants along with increased antioxidant enzymes activities and osmolyte contents. The field experiments revealed that seaweed extract-treated plants had significantly higher plant height and total yield under reduced irrigation compared to control plants, although both parameters remained lower than those seen under full irrigation. This study has produced encouraging findings on the application of SWE in crop systems, indicating that it may have a positive role in mitigating the effects of drought stress. [ABSTRACT FROM AUTHOR]

Salinity stress is a major problem affecting plant growth and crop productivity. While plant biostimulants have been reported to be an effective solution to tackle salinity stress in different crops, the key genes and metabolic pathways involved in these tolerance processes remain unclear. This study focused on integrating phenotypic, physiological, biochemical and transcriptome data obtained from different tissues of Solanum lycopersicum L. plants (cv. Micro-Tom) subjected to a saline irrigation water program for 61 days (EC: 5.8 dS/m) and treated with a combination of protein hydrolysate and Ascophyllum nodosum-derived biostimulant, namely PSI-475. The biostimulant application was associated with the maintenance of higher K+/Na+ ratios in both young leaf and root tissue and the overexpression of transporter genes related to ion homeostasis (e.g., NHX4, HKT1;2). A more efficient osmotic adjustment was characterized by a significant increase in relative water content (RWC), which most likely was associated with osmolyte accumulation and upregulation of genes related to aquaporins (e.g., PIP2.1, TIP2.1). A higher content of photosynthetic pigments (+19.8% to +27.5%), increased expression of genes involved in photosynthetic efficiency and chlorophyll biosynthesis (e.g., LHC, PORC) and enhanced primary carbon and nitrogen metabolic mechanisms were observed, leading to a higher fruit yield and fruit number (47.5% and 32.5%, respectively). Overall, it can be concluded that the precision engineered PSI-475 biostimulant can provide long-term protective effects on salinity stressed tomato plants through a well-defined mode of action in different plant tissues. [ABSTRACT FROM AUTHOR]

Reduction in the greenhouse gas (GHG) emissions and nitrogen (N) pollution of ground water by improving nitrogen use efficiency (NUE) in crops has become an intensively investigated research topic in pursuit of a more sustainable future. Although, distinct solutions have been proposed there are only a few reports documenting the detailed interplay between observed plant growth dynamics and changes in plant N related transcriptional and biochemical changes. It was previously demonstrated that the application of a formulated biostimulant (PSI-362) derived from Ascophyllum nodosum (ANE) improves N uptake in Arabidopsis thaliana and in barley. In this study, the effect of PSI-362 on the growth dynamics of wheat seedlings was evaluated at different biostimulant and N supplementation rates. Wheat grown on N deficient MS medium was also analysed from the first hour of the treatment until the depletion of the nutrients in the medium 9 days later. During this time the biomass increase measured for PSI-362 treated plants versus untreated controls was associated with increased nitrate uptake, with surplus N assimilated by the biomass in the form of glutamate, glutamine, free amino acids, soluble proteins, and chlorophyll. Phenotypical and biochemical analysis were supported by evaluation of differential expression of genetic markers involved in nitrate perception and transport (TaNRT1.1/NPF6.3), nitrate and nitrite reduction (TaNR1 and TaNiR1) and assimilation (TaGDH2, TaGoGAT, TaGS1). Finally, a comparative analysis of the precision biostimulant PSI-362 and two generic ANEs demonstrated that the NUE effect greatly differs depending on the ANE formulation used. [Display omitted] • Improving NUE in crops has become critical in pursuit of sustainable agriculture. • Ascophyllum nodosum extract biostimulant PSI-362 significantly improves winter wheat NUE. • PSI-362 enhanced biomass, nitrate uptake, and N assimilation under reduced and full N rate. • PSI-362 dysregulated genes involved in nitrate perception/transport and N assimilation. • NUE effect greatly differs depending on the ANE biostimulant used. [ABSTRACT FROM AUTHOR]

Salinity stress is a major problem affecting plant growth and crop productivity. While plant biostimulants have been reported to be an effective solution to tackle salinity stress in different crops, the key genes and metabolic pathways involved in these tolerance processes remain unclear. This study focused on integrating phenotypic, physiological, biochemical and transcriptome data obtained from different tissues of Solanum lycopersicum L. plants (cv. Micro-Tom) subjected to a saline irrigation water program for 61 days (EC: 5.8 dS/m) and treated with a combination of protein hydrolysate and Ascophyllum nodosum-derived biostimulant, namely PSI-475. The biostimulant application was associated with the maintenance of higher K+/Na+ ratios in both young leaf and root tissue and the overexpression of transporter genes related to ion homeostasis (e.g., NHX4, HKT1;2). A more efficient osmotic adjustment was characterized by a significant increase in relative water content (RWC), which most likely was associated with osmolyte accumulation and upregulation of genes related to aquaporins (e.g., PIP2.1, TIP2.1). A higher content of photosynthetic pigments (+19.8% to +27.5%), increased expression of genes involved in photosynthetic efficiency and chlorophyll biosynthesis (e.g., LHC, PORC) and enhanced primary carbon and nitrogen metabolic mechanisms were observed, leading to a higher fruit yield and fruit number (47.5% and 32.5%, respectively). Overall, it can be concluded that the precision engineered PSI-475 biostimulant can provide long-term protective effects on salinity stressed tomato plants through a well-defined mode of action in different plant tissues.

Most vegetable crops are salt sensitive, growing inadequately in salinised soils due to the accumulation of toxic ions from prolonged irrigation regimes. Plant biostimulants are a potential tool that can be used to counteract salinity stress and increase crop yield. The aim of this study was to investigate the ability of the proprietary protein hydrolysate and Ascophyllum nodosum-derived biostimulant PSI-475 to activate salinity stress tolerance responses in plants. After characterising PSI-475 composition, initial biostimulant activity screening was performed using Arabidopsis thaliana. PSI-475 stimulated primary root growth (+5.5–20.0%) and photosynthetic pigments content (18.8–63.0%) under unstressed and salinity stressed conditions. Subsequently, PSI-475 was assessed by foliar application on tomato plants (cv. Micro-Tom) that received a saline irrigation water program, which caused a significant decrease in fruit yield (−37.5%). Stressed plants treated with PSI-475 increased this parameter by 31.8% versus the stressed control. Experimental data suggest that PSI-475 can alleviate the negative effects of saline irrigation by improving osmotic adjustment and ion homeostasis markers. PSI-475 was also able to provide significant yield benefits in unstressed plants (+16.9%) that were associated with improved leaf biochemical markers. The data presented support the use of this precision biostimulant to target the negative effects of salinity stress from irrigation. [ABSTRACT FROM AUTHOR]

The effects of a commercial Ascophyllum seaweed extract (ASWE) on the growth parameters of sweet pepper plants were studied under grow box home garden conditions in the Caribbean. Grow box cultivation of vegetables in the backyard is very popular in Trinidad and Tobago and the wider Caribbean region. The use of synthetic chemicals should be avoided under home conditions due to the underlying hazards and for biosafety reasons. The application of ASWE at the rate of 0.5% as a foliar spray in sweet pepper plants under grow box home garden conditions improved the plant growth parameters, increased the fruit number, and also enhanced the shelf life of the harvested sweet pepper fruits. Soil drenching of ASWE to plants was less effective compared to foliar application. ASWE foliar spray also reduced the intensity of diseases and pests in plants and further promoted the prevalence of natural enemies. The spraying of ASWE significantly increased the biochemical constituents such as chlorophyll content, reducing sugars, phenol, and amino acids compared to the water control. The activity of the defense-related enzymes (chitinase, β-1,3 glucanase, peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase), and phenolic content was significantly greater in sweet pepper plants treated with ASWE treatment compared to the control. Seed treatment by priming in 0.5% ASWE significantly increased the germination percentage, shoot, and root length of seedlings. The positive effects of ASWE might be attributed to the chemical makeup, native to the seaweed extract, which is believed to contain several organic components, including dissolved nutrients and growth-promoting and diverse functional organic molecules that can induce multiple growth effects in plants. This study demonstrates that ASWE can be readily used under home garden conditions as this would be very conservative to the environment as well as promote the system of organic cultivation. [ABSTRACT FROM AUTHOR]

Intensive agricultural production utilizes large amounts of nitrogen (N) mineral fertilizers that are applied to the soil to secure high crop yields. Unfortunately, up to 65% of this N fertilizer is not taken up by crops and is lost to the environment. To compensate these issues, growers usually apply more fertilizer than crops actually need, contributing significantly to N pollution and to GHG emissions. In order to combat the need for such large N inputs, a better understanding of nitrogen use efficiency (NUE) and agronomic solutions that increase NUE within crops is required. The application of biostimulants derived from extracts of the brown seaweed Ascophyllum nodosum has long been accepted by growers as a sustainable crop production input. However, little is known on how Ascophyllum nodosum extracts (ANEs) can influence mechanisms of N uptake and assimilation in crops to allow reduced N application. In this work, a significant increase in nitrate accumulation in Arabidopsis thaliana 6 days after applying the novel proprietary biostimulant PSI-362 was observed. Follow-up studies in barley crops revealed that PSI-362 increases NUE by 29.85–60.26% under 75% N input in multi-year field trials. When PSI-362 was incorporated as a coating to the granular N fertilizer calcium ammonium nitrate and applied to barley crop, a coordinated stimulation of N uptake and assimilation markers was observed. A key indicator of biostimulant performance was increased nitrate content in barley shoot tissue 22 days after N fertilizer application (+17.9–72.2%), that was associated with gene upregulation of root nitrate transporters (NRT1.1, NRT2.1, and NRT1.5). Simultaneously, PSI-362 coated fertilizer enhanced nitrate reductase and glutamine synthase activities, while higher content of free amino acids, soluble protein and photosynthetic pigments was measured. These biological changes at stem elongation stage were later translated into enhanced NUE traits in harvested grain. Overall, our results support the agronomic use of this engineered ANE that allowed a reduction in N fertilizer usage while maintaining or increasing crop yield. The data suggests that it can be part of the solution for the successful implementation of mitigation policies for water quality and GHG emissions from N fertilizer usage.

Intensive agricultural production utilizes large amounts of nitrogen (N) mineral fertilizers that are applied to the soil to secure high crop yields. Unfortunately, up to 65% of this N fertilizer is not taken up by crops and is lost to the environment. To compensate these issues, growers usually apply more fertilizer than crops actually need, contributing significantly to N pollution and to GHG emissions. In order to combat the need for such large N inputs, a better understanding of nitrogen use efficiency (NUE) and agronomic solutions that increase NUE within crops is required. The application of biostimulants derived from extracts of the brown seaweed Ascophyllum nodosum has long been accepted by growers as a sustainable crop production input. However, little is known on how Ascophyllum nodosum extracts (ANEs) can influence mechanisms of N uptake and assimilation in crops to allow reduced N application. In this work, a significant increase in nitrate accumulation in Arabidopsis thaliana 6 days after applying the novel proprietary biostimulant PSI-362 was observed. Follow-up studies in barley crops revealed that PSI-362 increases NUE by 29.85–60.26% under 75% N input in multi-year field trials. When PSI-362 was incorporated as a coating to the granular N fertilizer calcium ammonium nitrate and applied to barley crop, a coordinated stimulation of N uptake and assimilation markers was observed. A key indicator of biostimulant performance was increased nitrate content in barley shoot tissue 22 days after N fertilizer application (+17.9–72.2%), that was associated with gene upregulation of root nitrate transporters (NRT1.1 , NRT2.1 , and NRT1.5). Simultaneously, PSI-362 coated fertilizer enhanced nitrate reductase and glutamine synthase activities, while higher content of free amino acids, soluble protein and photosynthetic pigments was measured. These biological changes at stem elongation stage were later translated into enhanced NUE traits in harvested grain. Overall, our results support the agronomic use of this engineered ANE that allowed a reduction in N fertilizer usage while maintaining or increasing crop yield. The data suggests that it can be part of the solution for the successful implementation of mitigation policies for water quality and GHG emissions from N fertilizer usage. [ABSTRACT FROM AUTHOR]

Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant's active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes.

Soybean is one of the most valuable commercial crops because of its high protein, carbohydrate, and oil content. The land area cultivated with soybean in subtropical regions, such as Brazil, is continuously expanding, in some instances at the expense of carbon storing natural habitats. Strategies to decrease yield/seed losses and increase production efficiency are urgently required to meet global demand for soybean in a sustainable manner. Here, we evaluated the effectiveness of an Ascophyllum nodosum extract (ANE), SealicitTM, in increasing yields of different soybean varieties, in two geographical regions (Canada and Brazil). In addition, we investigated the potential of SealicitTM to reduce pod shattering at the trials in Brazil. Three different concentrations of SealicitTM were applied to pod shatter-susceptible (SS) UFUS 6901 and shatter-resistant (SR) UFUS 7415 varieties to assess their impact on pod firmness. SS variety demonstrated a significant decrease in pod shattering, which coincided with deregulation of GmPDH1.1 and GmSHAT1–5 expression, genes that determine pod dehiscence, and higher seed weight per pod. SealicitTM application to the SR variety did not significantly alter its inherent pod shatter resistance, but provided higher increases in seed yield at harvest. This yield increase maybe associated with to other yield components stimulated by the biostimulant. This work demonstrates that SealicitTM, which has previously been shown to improve pod firmness in Arabidopsis and selected commercial oilseed rape varieties through IND gene down-regulation, also has the potential to improve pod resistance and seed productivity in soybean, a member of the legume family sharing a similar strategy for seed dispersal.

Soybean is one of the most valuable commercial crops because of its high protein, carbohydrate, and oil content. The land area cultivated with soybean in subtropical regions, such as Brazil, is continuously expanding, in some instances at the expense of carbon storing natural habitats. Strategies to decrease yield/seed losses and increase production efficiency are urgently required to meet global demand for soybean in a sustainable manner. Here, we evaluated the effectiveness of an Ascophyllum nodosum extract (ANE), SealicitTM, in increasing yields of different soybean varieties, in two geographical regions (Canada and Brazil). In addition, we investigated the potential of SealicitTM to reduce pod shattering at the trials in Brazil. Three different concentrations of SealicitTM were applied to pod shatter-susceptible (SS) UFUS 6901 and shatter-resistant (SR) UFUS 7415 varieties to assess their impact on pod firmness. SS variety demonstrated a significant decrease in pod shattering, which coincided with deregulation of GmPDH1.1 and GmSHAT1–5 expression, genes that determine pod dehiscence, and higher seed weight per pod. SealicitTM application to the SR variety did not significantly alter its inherent pod shatter resistance, but provided higher increases in seed yield at harvest. This yield increase maybe associated with to other yield components stimulated by the biostimulant. This work demonstrates that SealicitTM, which has previously been shown to improve pod firmness in Arabidopsis and selected commercial oilseed rape varieties through IND gene down-regulation, also has the potential to improve pod resistance and seed productivity in soybean, a member of the legume family sharing a similar strategy for seed dispersal. [ABSTRACT FROM AUTHOR]

Phosphorous is one of the major limiting factors determining plant growth. Current agricultural practices mainly rely on the use of chemical fertilizers posing threat to the ecosystem. In this study, the application of an Ascophyllum nodosum extract (ANE) in phosphorous (P)-limited conditions improved the fresh and dry weight of shoots and roots of Zea mays. ANE-treated Z. mays grown under P-limited conditions showed a higher P content than the control. ANE activated simultaneous responses, at multiple levels, in Z. mays grown under P-limited conditions as seen from the regulation of gene expression at the whole-plant level to specific biochemical responses on a subcellular level. ANE-supplemented Z. mays grown under P-limited conditions also showed reduced electrolyte leakage and lipid peroxidation by an improved membrane stability. ANE treatment reduced P-limitation-induced oxidative damage in Z. mays by reducing H2O2 and O2- accumulation. Furthermore, ANE also induced the accumulation of the total contents of soluble sugars, amino acids, phenolics, and flavonoids. Gene expression analysis suggested that ANE differentially modulated the expression of P-starvation responsive genes involved in metabolic, signal transduction, and developmental pathways in Z. mays. ANE also modulated the expression of genes involved in sugar, lipid, and secondary metabolism. Thus, this study illustrated the role of ANE in improving the productivity of Z. mays, an important crop, in P-limited conditions. Furthermore, it sets the framework to increase agricultural productivity in nutrient deficient soils using a sustainable, eco-friendly strategy.

Most vegetable crops are salt sensitive, growing inadequately in salinised soils due to the accumulation of toxic ions from prolonged irrigation regimes. Plant biostimulants are a potential tool that can be used to counteract salinity stress and increase crop yield. The aim of this study was to investigate the ability of the proprietary protein hydrolysate and Ascophyllum nodosum-derived biostimulant PSI-475 to activate salinity stress tolerance responses in plants. After characterising PSI-475 composition, initial biostimulant activity screening was performed using Arabidopsis thaliana. PSI-475 stimulated primary root growth (+5.5–20.0%) and photosynthetic pigments content (18.8–63.0%) under unstressed and salinity stressed conditions. Subsequently, PSI-475 was assessed by foliar application on tomato plants (cv. Micro-Tom) that received a saline irrigation water program, which caused a significant decrease in fruit yield (−37.5%). Stressed plants treated with PSI-475 increased this parameter by 31.8% versus the stressed control. Experimental data suggest that PSI-475 can alleviate the negative effects of saline irrigation by improving osmotic adjustment and ion homeostasis markers. PSI-475 was also able to provide significant yield benefits in unstressed plants (+16.9%) that were associated with improved leaf biochemical markers. The data presented support the use of this precision biostimulant to target the negative effects of salinity stress from irrigation.

Phosphorous is one of the major limiting factors determining plant growth. Current agricultural practices mainly rely on the use of chemical fertilizers posing threat to the ecosystem. In this study, the application of an Ascophyllum nodosum extract (ANE) in phosphorous (P)-limited conditions improved the fresh and dry weight of shoots and roots of Zea mays. ANE-treated Z. mays grown under P-limited conditions showed a higher P content than the control. ANE activated simultaneous responses, at multiple levels, in Z. mays grown under P-limited conditions as seen from the regulation of gene expression at the whole-plant level to specific biochemical responses on a subcellular level. ANE-supplemented Z. mays grown under P-limited conditions also showed reduced electrolyte leakage and lipid peroxidation by an improved membrane stability. ANE treatment reduced P-limitation-induced oxidative damage in Z. mays by reducing H2O2 and O 2 - accumulation. Furthermore, ANE also induced the accumulation of the total contents of soluble sugars, amino acids, phenolics, and flavonoids. Gene expression analysis suggested that ANE differentially modulated the expression of P-starvation responsive genes involved in metabolic, signal transduction, and developmental pathways in Z. mays. ANE also modulated the expression of genes involved in sugar, lipid, and secondary metabolism. Thus, this study illustrated the role of ANE in improving the productivity of Z. mays , an important crop, in P-limited conditions. Furthermore, it sets the framework to increase agricultural productivity in nutrient deficient soils using a sustainable, eco-friendly strategy. [ABSTRACT FROM AUTHOR]

The fertilizers that are derived from seaweed are known as Seaweed Liquid Fertilizers (SLF). SLF is a modern, cheap, non-toxic, and natural bioactive fertilizer. Among different studied seaweeds, Ascophyllum nodosum is significant as having bioactive ingredients that potentially regulate the molecular, physiological, and biochemical processes of crop plants. In the present study, the effects of the application of different concentrations (0.00%, 0.01%, 0.02%, 0.05%, 0.10%, 0.50%, and 1.00%) of A. nodosum Extract (ANE) to the Vigna aconitifolia through roots (Pot Root Application, PRA) and on the leaves (Pot Foliar Application, PFA) were monitored via the plant growth. The lower concentrations of ANE in both the PRA and PFA experiments showed positive growth on V. aconitifolia. The 0.10% ANE stimulated the maximum shoot growth when applied through the roots, while 0.05% ANE in both PFA and PRA experiments led to an increase in the number of pods, nodules, organic content, and moisture percentage. The 0.10% ANE also increased the leaf numbers, leaf area, and photosynthetic pigments. Hence, the application of 0.05% and 0.10% of A. nodosum extract in two ways (i.e., Pot Foliar Application, PFA, and Pot Root Application, PRA) ameliorated the growth capabilities of V. aconitifolia.

Global changes in climate are leading to increased occurrence and duration of drought episodes with concurrent reduction in crop yields. Expansion of the irrigated land area does not appear to be a viable solution in many regions to deliver crop productivity. The development of crop drought tolerance traits by either genetic modification or plant breeding represent the principal approaches to meeting this challenge to date. Biostimulants are an emerging category of crop management products which can enhance crop productivity under abiotic stress conditions. The ability of some biostimulant products such as Ascophyllum nodosum extracts (ANE) to enhance the tolerance of crops to drought stress has been observed by growers. The objective of this study was to investigate if different commercial ANE biostimulants provided the same tolerance to tomato plants (cv. Moneymaker) subjected to a defined drought period. A compositional characterisation of the key macromolecules of ANEs was performed. In addition, the role of ANE biostimulants in inducing changes of chlorophyll and osmolytes levels, MDA production, dehydrin isoform pattern and dehydrin gene expression levels was assessed. The three ANE biostimulants evaluated were found to provide different levels of tolerance to drought stressed tomato plants. The level of drought tolerance provided was related to changes in the concentration of osmolytes and expression of tas14 dehydrin gene. Taken together, our results highlight that despite the fact all ANE biostimulants were manufactured from the same raw material, their ability to maintain crop productivity during and after drought stress was not the same. [ABSTRACT FROM AUTHOR]

The fertilizers that are derived from seaweed are known as Seaweed Liquid Fertilizers (SLF). SLF is a modern, cheap, non-toxic, and natural bioactive fertilizer. Among different studied seaweeds, Ascophyllum nodosum is significant as having bioactive ingredients that potentially regulate the molecular, physiological, and biochemical processes of crop plants. In the present study, the effects of the application of different concentrations (0.00%, 0.01%, 0.02%, 0.05%, 0.10%, 0.50%, and 1.00%) of A. nodosum Extract (ANE) to the Vigna aconitifolia through roots (Pot Root Application, PRA) and on the leaves (Pot Foliar Application, PFA) were monitored via the plant growth. The lower concentrations of ANE in both the PRA and PFA experiments showed positive growth on V. aconitifolia. The 0.10% ANE stimulated the maximum shoot growth when applied through the roots, while 0.05% ANE in both PFA and PRA experiments led to an increase in the number of pods, nodules, organic content, and moisture percentage. The 0.10% ANE also increased the leaf numbers, leaf area, and photosynthetic pigments. Hence, the application of 0.05% and 0.10% of A. nodosum extract in two ways (i.e., Pot Foliar Application, PFA, and Pot Root Application, PRA) ameliorated the growth capabilities of V. aconitifolia. [ABSTRACT FROM AUTHOR]

Soybean is one of the most valuable commercial crops because of its high protein, carbohydrate, and oil content. The land area cultivated with soybean in subtropical regions, such as Brazil, is continuously expanding, in some instances at the expense of carbon storing natural habitats. Strategies to decrease yield/seed losses and increase production efficiency are urgently required to meet global demand for soybean in a sustainable manner. Here, we evaluated the effectiveness of an Ascophyllum nodosum extract (ANE), Sealicit TM , in increasing yields of different soybean varieties, in two geographical regions (Canada and Brazil). In addition, we investigated the potential of Sealicit TM to reduce pod shattering at the trials in Brazil. Three different concentrations of Sealicit TM were applied to pod shatter-susceptible (SS) UFUS 6901 and shatter-resistant (SR) UFUS 7415 varieties to assess their impact on pod firmness. SS variety demonstrated a significant decrease in pod shattering, which coincided with deregulation of GmPDH1.1 and GmSHAT1-5 expression, genes that determine pod dehiscence, and higher seed weight per pod. Sealicit TM application to the SR variety did not significantly alter its inherent pod shatter resistance, but provided higher increases in seed yield at harvest. This yield increase maybe associated with to other yield components stimulated by the biostimulant. This work demonstrates that Sealicit TM , which has previously been shown to improve pod firmness in Arabidopsis and selected commercial oilseed rape varieties through IND gene down-regulation, also has the potential to improve pod resistance and seed productivity in soybean, a member of the legume family sharing a similar strategy for seed dispersal., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Łangowski, Goñi, Marques, Hamawaki, da Silva, Nogueira, Teixeira, Glasenapp, Pereira and O’Connell.)

Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant's active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes., (© The Korean Society of Plant Pathology.)

Biostimulants for crop management are gaining increased attention with continued demand for increased crop yields. Seaweed extracts represent one category of biostimulant, with Ascophyllum nodosum extracts (ANE) widely used for yield and quality enhancement. This study investigated how the composition of two ANE biostimulants (ANE A and ANE B) affects plant mRNA transcriptomes, using the model plant Arabidopsis thaliana. Using Affymetrix Ath1 microarrays, significant heterogeneity was detected between the ANE biostimulants in terms of their impacts on the mRNA transcriptome of A. thaliana plants, which accumulated significantly more biomass than untreated controls. Genes dysregulated by the ANE biostimulants are associated with a wide array of predicted biological processes, molecular functions, and subcellular distributions. ANE A dysregulated 4.47% of the transcriptome, whereas ANE B dysregulated 0.87%. The compositions of both ANEs were significantly different, with a 4-fold difference in polyphenol levels, the largest observed. The standardization of the composition of ANE biostimulants represents a challenge for providing consistent effects on plant gene expression and biostimulation.