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Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a threat to maize production systems, is a polyphagous pest of global significance. There is no registered bioinsecticide of botanical origin to provide green remedy against this pest of concern. The present study reports for the first time the potency of the polar and non-polar bioinsecticidal leads sourced from Lippia alba (Mill.) N.E. Br. leaves. Shade-dried leaves of L. alba were extracted and evaluated; based on preliminary bioassay, the ethyl acetate leaf extract of L. alba (LEAE) was found to be the most potent against FAW in the in vitro and in vivo studies. Ultraperformance liquid chromatography–quadrupole time-of-flight–mass spectrometric (UPLC-QToF-MS) analysis of LEAE revealed the rich chemical profile of 28 compounds, dominated by flavones, namely, naringenin, trihydroxy-dimethoxy flavone, and dihydroxy-trimethoxy flavone. Among others, glycosides, such as clerodendrin, calceolarioside E, forsythoside B, geniposide, and martynoside, and glucuronides, such as luteolin-7-diglucuronide, tricin-7-O-glucuronide, and luteolin-7-O-glucuronide, were also identified. LEAE exhibited exceptionally high in vitro [LC50 = 6,900 parts per million (ppm)] and in vivo (computed as damage score on a scale of 1–9) insecticidal activity against S. frugiperda, with no phytotoxicity at a dose as high as 20 times of LC50. LEAE also exhibited significant antifeedant, ovicidal, and growth regulatory activity at the 70–16,000 ppm (w/v) concentration range. In silico assessment revealed strong binding of martynoside, calceolarioside E, and forsythoside B with acetylcholinesterase-, sodium-, and chloride-dependent γ-aminobutyric acid (GABA) receptor and ryanodine receptor, respectively, facilitated by hydrogen bonds (conventional and C–H bonds) stabilized by hydrophobic pi–sigma, pi–pi stacked, pi–alkyl, and alkyl interactions. The present study established L. alba as a potential bioresource and secondary metabolite enriched LEAE as bioinsecticide for further product development.

This study aimed to assess the chemical composition and pesticidal activities of essential oils (EOs) from Cautleya spicata rhizomes and aerial parts. The EOs were assessed against root-knot nematodes (Meloidogyne incognita) by mortality and hatchability bioassays and the phytotoxicity of the EOs was determined against Raphanus raphanistrum subspp. Sativus (radish) and Cichorium intybus (chicory) seeds. In-silico screening of the primary constituents of EOs and five chosen target proteins of the nematode was conducted to predict the expected mechanism of action of these oils. p-Cymene and β-pinene were the key compounds in the EOs from the rhizomes and aerial parts. The EO from the aerial parts (LC50 value = 0.555 µL/mL for nematode mortality assay and IC50 value = 0.016 µL/mL for nematode egg hatchability after 96 h) exhibited significantly higher nematicidal activity than the rhizome EO. However, rhizome EO showed higher phytotoxic activity against radish (R. raphanistrum) with lower IC50 values (0.157 and 0.123 µL/mL for RLI and SLI, respectively) and chicory (C. intybus) seeds (100% inhibition at 1.0 µL/mL concentration). Docking studies revealed the strongest inhibitory actions of β-selinene against acetylcholinesterase (AChE) and cytochrome c oxidase (CytC), spathulenol against glutathione S-transferase (GST-1), and β-eudesmol against heat shock protein 90 (HSP90) and odorant response gene-3 (ODR3) proteins. The study unveiled the chemical diversity present in both the EOs and rhizomes of C. spicata along with their considerable potential as plant-based pesticidal agents effective against nematodes and weed species.

Background: In West Bengal, India, a huge amount of lignocellulosic jute waste products, in the form of unutilized cut pieces of jute caddies consisting 65% cellulose, 22.5% hemicellulose, and 11% lignin, is generated from jute industries. Naturally, the high percentage of lignocellulolytic material made it an attractive substrate for the hydrolytic cleavage of lignocellulolytic enzymes, namely xylanases and cellulases. The present study aims for the production of xylanolytic and cellulolytic enzymes by a fungal isolate Penicillium janthinellum MTCC10889 using a cheap medium containing residual jute caddies obtained from jute mill wastes and chemically defined basal medium under submerged fermentation. Results: The fungal isolate P. janthinellum MTCC10889 is an outstanding producer of endoxylanase and also cellulase. A central composite design was applied to optimize its lignocellulolytic as well as cellulolytic enzyme production in submerged-state fermentation. The impact of three quantitative variables, namely pH, temperature, and substrate concentrations, on enzyme production was investigated by using a chemically defined basal medium supplemented with jute caddy as substrate. Such optimum conditions were as follows: pH 7.47, temperature of 30.35°C, and substrate concentration of 1.70% for endoxylanase, and pH 7.51, temperature of 29.69°C, and substrate concentration of 2.11% for cellulase production. Conclusions: A combination of one-factor-at-a-time approach is replaced by response surface methodology using central composite design, which resulted in 3.08- and 3.84-fold increases in the yields of endoxylanase (1,750 IU/ml) and endoglucanase (192 IU/ml), respectively. The highest endoxylanase and endoglucanase productions under optimized conditions were achieved within 48 h of growth.

In mango pickle industry, a significant quantity of mango seed kernels is discarded as solid wastes. These seed kernels can be an ideal source for obtaining extracts rich in bioactive polyphenolic compounds with good antioxidant properties. The potential of mango kernel phenolic extract (MKPE) was investigated as a natural and effective antimicrobial agent for controlling major postharvest fungal pathogen infections, a significant threat to global food supply chains. Fungal pathogens contribute to the deterioration of fruits, vegetables, and grains during storage and transportation, leading to economic losses and compromised food safety. MKPE was obtained from pickling variety 'Ramkela' raw mango kernels, and its phenolic composition was characterized using LC–MS. The in vitro antifungal activity of MKPE against Botrytis cinerea, Colletotrichum gloeosporoides, and Rhizopus stolonifer was evaluated in vitro. A concentration-dependent inhibition of fungal radial growth against all three pathogens was observed, exhibiting the potential of MKPE as a valuable natural resource for addressing postharvest losses caused by fungal pathogens. The extraction process yielded a total phenolic content of 2128 mg GAE/100 g. Major polyphenolic bioactive compounds present were mangiferin, quercetin, and rhamnetin. The in-vitro antimicrobial assay showed reduction in the radial growth and inhibition percent of the pathogens. EC50 values of MKPE for B. cineria, C. gloeosporoides, and R. stolonifer was found to 364.17, 963.8 and 926 ppm, respectively. Our results demonstrate an economical, sustainable, and eco-friendly approach to manage post-harvest diseases rendered by fungi using mango MKPE from pickling industry waste.

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. The fungus Aspergillus niger is known to produce diverse metabolites with antifungal activity, attracting researchers to exploit it as a bio-control agent for plant disease control. In the present study, 11 A. niger strains were isolated and screened for their antagonism against the guava wilt pathogen under in vitro and in planta conditions. Strains were identified morphologically and molecularly by sequencing the internal transcribed spacer (ITS), β-tubulin, and calmodulin genes. The strains were evaluated through dual culture, volatile, and non-volatile methods under an in vitro study. AN-11, AN-6, and AN-2 inhibited the test pathogen Fusarium oxysporum f. sp. psidii (FOP) at 67.16%, 64.01%, and 60.48%, respectively. An in planta study was conducted under greenhouse conditions with 6 months old air-layered guava plants (var. Allahabad Safeda) by pre- and post-inoculation of FOP. The AN-11 strain was found to be effective under both pre- and post-inoculation trials. Furthermore, gas chromatography–mass spectrometry (GC–MS) analysis was carried out to characterize the volatile compounds of the most potential strain, A. niger. The hexane soluble fraction showed the appearance of characteristic peaks of hexadecenoic acid methyl ester (4.41%), 10-octadecanoic acid methyl ester (3.79%), dodecane (3.21%), undecane (3.19%), gibepyrone A (0.15%), 3-methylundecane (0.36%), and citroflex A (0.38%). The ethyl acetate fraction of the bio-control fungi revealed the occurrence of major antifungal compounds, such as acetic acid ethyl ester (17.32%), benzopyron-4-ol (12.17%), 1,2,6-hexanetriol (7.16%), 2-propenoic acid ethanediyl ester (2.95%), 1-(3-ethyloxiranyl)-ethenone (0.98%), 6-acetyl-8-methoxy dimethyl chromene (0.96%), 4-hexyl-2,5-dihydro dioxo furan acetic acid (0.19%), and octadecanoic acid (1.11%). Furthermore, bio-control abilities could be due to hyper-parasitism, the production of secondary metabolites, and competition for sites and nutrients. Indeed, the results will enrich the existing knowledge of metabolomic information and support perspectives on the bio-control mechanism of A. niger.

In present study, different varieties of chrysanthemum (Chrysanthemum × morifolium Ramat) were screened for total carotenoids, phenolic content and antioxidant activities. Among the genotypes studied, variety Jubilee (32.82 mg/100g) exhibited high total carotenoids followed by varieties Haldighati (26.71 mg/100 g), Little Orange (22.25 mg/100g), Liliput (20.77 mg/100g) and Star Yellow (19.21 mg/100g). Variety Jubilee also showed highest antioxidant activities of carotenoids {CUPRAC-Cupric reducing antioxidant capacity (149.44 μmol trolox/g), FRAP- Ferrous reducing power (40.09 %), DPPH radical scavenging activity (11.24%)}. The total phenolic content varied from 1.26 mg GAE/g (Ram Lal Dada) to 31.14 mg GAE/g (Jubilee) on fresh weight basis. Further, five promising varieties having high carotenoids, were quantified for lutein and β-carotene using High Performance Liquid Chromatography (HPLC). Highest lutein content was found in variety Jubilee (19.90 μg/g) followed by varieties Haldighati (8.67 μg /g), Liliput (4.77 μg /g), Star Yellow (3.93 μg /g) and Little Orange (3.69 μg/g). Highest β-carotene content was found in Little Orange (5.51μg/g) followed by the varieties Haldighati (2.04 μg /g), Jubilee (1.77 μg /g), Liliput (0.54 μg /g) and Star Yellow (0.50 μg/g). A high correlation between carotenoids, total phenolic and antioxidant activities was observed. Variety Sadwin Yellow showed highest total carotenoid (0.48 mg/g) in leaves, whereas chlorophyll a and total chlorophyll was highest in variety Punjab Anmol (1.32 mg/g, 1.56 mg/g) and high chlorophyll b in variety Pusa Aditya (0.28 mg/g).

Three native rhizobacteria, IRh9, IRh10 and IRh15, were isolated from nematode-infected tomato (Solanum lycopersicum L.) rhizosphere were characterized and evaluated for their efficacy against root-knot nematode (RKN), Meloidogyne incognita infecting tomato crop under pot conditions in the protected structure environment during 2020–21 at Centre for Protected Cultivation technology (CPCT), ICAR-Indian Agricultural Research Institute, New Delhi. Based on 16S rRNA sequences, IRh9, IRh10, and IRh15 showed > 98% homology with Bacillus licheniformis, Priestia megaterium and Pseudomonas putida, respectively. Compared to the control, the penetration of root-knot nematode in tomato roots was reduced by >50% under pot conditions through inoculation of these bacteria. Characterization through gas chromatography-mass spectrometry analysis revealed 30 different volatile organic compounds from these rhizobacteria. Among them, 19 compounds were identified from P. megaterium IRh10, followed by 16 compounds each from B. licheniformis IRh9 and P. putida IRh15. Furthermore, among the detected volatile organic compounds, acetic acid, hexadecane, hexadecanoic acid, octadecanoic acid, 1-decene and 9-octadeconoic acid are reported to possess nematicidal properties. Additional characterization of plant growth promotion traits associated with these rhizobacteria revealed that P. megaterium IRh10 and P. putida IRh15 produced indole acetic acid, while B. licheniformis IRh9 and P. megaterium IRh10 produced ammonia, but only P. putida IRh15 could solubilize the tricalcium phosphate under laboratory conditions. Among the 35 substrates studied, P. megaterium IRh10 utilized most (12), followed by B. licheniformis IRh9 and P. putida IRh15, which were able to use 11 and 8 substrates, respectively. The study showed that B. licheniformis IRh9, P. megaterium IRh10 and P. putida IRh15 are potential candidates for combating M. incognita infestation in tomato crops.

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. Among them, Trichoderma is commonly used as a biological control agent in plant disease management due to its ability to suppress soil-borne plant pathogens. In the present study, 20 Trichoderma asperellum isolates were collected from different geographical locations and confirmed using morphological characteristics and molecular phylogenetic inferences based on combined ITS and β-tubulin sequences. All twenty isolates were screened for their antagonism against the collar rot pathogen under in vitro and in planta conditions. The isolates were evaluated through dual culture and volatile methods in an in vitro study. Isolate A10 inhibited the test pathogen Agroathelia rolfsii at 94.66% in a dual culture assay and 70.95% in a volatile assay, followed by the isolates A11 and A17, which recorded 82.64% and 81.19% in dual culture assay and 63.75% and 68.27% in the volatile assay respectively. An in planta study was conducted under greenhouse conditions in tomato var. pusa ruby by pre- and post-inoculation of T. asperellum isolates in the A. rolfsii infected soil to evaluate their antagonistic potential against the disease. The A10 isolate was found effective under both pre- and post-inoculation conditions, with a disease inhibition percent of 86.17 and 80.60, respectively, followed by the isolates A11 and A17, which exhibited inhibition of 77.80% and 75.00% in pre-inoculation and 72.22% and 69.44% in post-inoculation, respectively. Further, biochemical analysis was conducted to determine the specific activity of hydrolytic enzymes produced by T. asperellum during interaction with A. rolfsii. We found that isolate A10 produces more hydrolytic enzymes with the specific activity of 174.68 IU/mg of β-1,3 glucanase, 183.48 IU/mg of β-1, 4 glucanase, 106.06 IU/mg of protease, followed by isolate A17, A11 respectively. In GC-MS analysis, we observed maximum anti-microbial volatile organic compounds from the isolate A10, including 2H-Pyran-2-one (17.39%), which was found to be most abundant, followed by dienolactone (8.43%), α-pyrone (2.19%), and harziandione (0.24%) respective retention time of 33.48, 33.85, 33.39, and 64.23 min, respectively, compared to other isolates. In the TLC assay, we observed that a greater number of bands were produced by the A10 and A17 isolates in the Hexane: Ethyl Acetate (1:1) solvent system than in the 9:1 solvent system, which represents the presence of major metabolites in the ethyl acetate extract.

Genetic and functional characteristics of rice leaf endophytic actinobacterial member, Microbacterium are described. Morphotyping, multilocus sequence analysis and transmission electron microscopy indicated the species identity of the endophytic bacterium, OsEnb-ALM-D18, as Microbacterium testaceum. The endophytic Microbacterium showed probiotic solubilization of plant nutrients/minerals, produced hydrolytic enzyme/phytohormones, and showed endophytism in rice seedlings. Further, the endophytic colonization by M. testaceum OsEnb-ALM-D18 was confirmed using reporter gene coding for green fluorescence protein. Microbacterium OsEnb-ALM-D18 showed volatilome-mediated antibiosis (95.5% mycelial inhibition) on Magnaporthe oryzae. Chemical profiling of M. testaceum OsEnb-ALM-D18 volatilome revealed the abundance of 9-Octadecenoic acid, Hexadecanoic acid, 4-Methyl-2-pentanol, and 2,5-Dihydro-thiophene. Upon endobacterization of rice seedlings, M. testaceum altered shoot and root phenotype suggestive of activated defense. Over 80.0% blast disease severity reduction was observed on the susceptible rice cultivar Pusa Basmati-1 upon foliar spray with M. testaceum. qPCR-based gene expression analysis showed induction of OsCERK1, OsPAD4, OsNPR1.3, and OsFMO1 suggestive of endophytic immunocompetence against blast disease. Moreover, M. testaceum OsEnb-ALM-D18 conferred immunocompetence, and antifungal antibiosis can be the future integrated blast management strategy.

BackgroundAntioxidants detain the development and proliferation of various non-communicable diseases (NCDs). γ-oryzanol, a group of steryl ferulates and caffeates, is a major antioxidant present in rice grain with proven health benefits. The present study evaluated the distribution and dynamics of γ-oryzanol and its components in spatial and temporal scales and also delineated the effect of processing and cooking on its retention.MethodsSix rice varieties (four Basmati and two non-Basmati) belonging to indica group were analyzed at spatial scale in four different tissues (leaf blades, leaf sheaths, peduncle and spikelets) and temporal scale at three developmental stages (booting, milky and dough). Additionally, the matured grains were fractioned into husk, embryo, bran, and endosperm to assess differential accumulation in these tissues. Further, milling and cooking of the samples was done to assess the retention upon processing. After extraction of γ-oryzanol by solvent extraction method, individual components were identified by UPLC-QToF-ESI-MS and quantified by RP-HPLC.ResultsThe non-seed tissues were significantly different from the seed tissues for composition and quantitative variation of γ-oryzanol. Cycloartenyl caffeate was predominant in all the non-seed tissues during the three developmental stages while it showed significant reduction during the growth progression toward maturity and was totally absent in the matured grains. In contrary, the 24-methylenecycloartanyl ferulate, campesteryl ferulate and β-sitosteryl ferulate showed significant increment toward the growth progression to maturity. Milling caused significant reduction, retaining only an average of 58.77% γ-oryzanol. Cooking of brown rice in excess water showed relatively lower average retention (43.31%) to samples cooked in minimal water (54.42%). Cooked milled rice showed least mean retention of 21.66%.ConclusionThe results demonstrate prominent compositional variation of γ-oryzanol during different growth stages. For the first time, the study demonstrated that ferulate esters of γ-oryzanol were predominant in the seed tissues while caffeate esters were dominant in non-seed tissues. Basmati cultivars show differential expression of γ-oryzanol and its components compared to non-Basmati cultivars. Cooking in excess water causes maximum degradation of γ-oryzanol. Post-harvest losses due to milling and cooking indicate the necessity of biofortification for γ-oryzanol content in rice grain.

In developing a Trichoderma viride-based biocontrol program for Fusarium wilt disease in chickpea, the choice of the quality formulation is imperative. In the present study, two types of formulations i.e. powder for seed treatment (TvP) and tablet for direct application (TvT), employing T. viride as the biocontrol agent, were evaluated for their ability to control chickpea wilt under field conditions at three dosages i.e. recommended (RD), double of recommended (DD) and half of recommended (1/2 RD). A screening study for the antagonistic fungi strains based on volatile and non-volatile bioassays revealed that T. viride ITCC 7764 has the most potential among the five strains tested (ITCC 6889, ITCC 7204, ITCC 7764, ITCC 7847, ITCC 8276), which was then used to develop the TvP and TvT formulations. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of volatile organic compounds (VOCs) of T. viride strain confirmed the highest abundance of compositions comprising octan-3-one (13.92%), 3-octanol (10.57%), and 1-octen-3-ol (9.40%) in the most potential T. viride 7764. Further Physico-chemical characterization by standard Collaborative International Pesticides Analytical Council (CIPAC) methods revealed the optimized TvP formulation to be free flowing at pH 6.50, with a density of 0.732 g cm-3. The TvT formulation showed a pH value of 7.16 and density of 0.0017 g cm-3 for a complete disintegration time of 22.5 min. The biocontrol potential of TvP formulation was found to be superior to that of TvT formulation in terms of both seed germination and wilt incidence in chickpea under field conditions. However, both the developed formulations (TvP and TvT) expressed greater bioefficacy compared to the synthetic fungicide (Carbendazim 50% WP) and the conventional talc-based formulation. Further research should be carried out on the compatibility of the developed products with other agrochemicals of synthetic or natural origin to develop an integrated disease management (IDM) schedule in chickpea.

Cucumber is a model plant for studying parthenocarpy with abundant slicing- and pickling-type germplasm. This study was undertaken to understand the role of the important cytokines (CKs), auxin (AUX) and gibberellin (GA) biosynthesis and degradation genes for the induction of parthenocarpy in slicing and pickling germplasm. Two genotypes of gynoecious parthenocarpic cucumber, PPC-6 and DG-8, along with an MABC-derived gynoecious non-parthenocarpic line, IMPU-1, were evaluated in this study. The slicing and pickling cucumber genotypes PPC-6 and DG-8 were strongly parthenocarpic in nature and set fruit normally without pollination. Endogenous auxin and gibberellin were significantly higher in parthenocarpic than non-parthenocarpic genotypes, whereas the concentration of cytokinins varied among the genotypes at different developmental stages. However, the exogenous application of Zeatin and IAA + Zeatin was effective in inducing parthenocarpic fruit in IMPU-1. Expression analysis with important CK, AUX, and GA biosynthesis-related genes was conducted in IMPU-1, PPC-6, and DG-8. The expression of the CK synthase, IPT, IPT3, PaO, LOG1, LOG2, CYP735A1, and CYP735A2 was up-regulated in the parthenocarpic genotypes. Among the transcription factor response regulators (RRs), positive regulation of CSRR8/9b, CSRR8/9d, CSRR8/9e, and CSRR16/17 and negative feedback of the CK signalling genes, such as CsRR3/4a, CsRR3/4b, CsRR8/9a, and CsRR8/9c, were recorded in the parthenocarpic lines. Homeostasis between cytokinin biosynthesis and degradation genes such as CK oxidases (CKXs) and CK dehydrogenase resulted in a non-significant difference in the endogenous CK concentration in the parthenocarpic and non-parthenocarpic genotypes. In addition, up-regulation of the key auxin-inducing proteins and GA biosynthesis genes indicated their crucial role in the parthenocarpic fruit set of cucumber. This study establishes the critical role of the CKs, AUX, and GA regulatory networks and their cross-talk in determining parthenocarpy in slicing and pickling cucumber genotypes.

Microbial degradation is an effective, eco-friendly and sustainable approach for management of the rice residue. After harvesting a rice crop, removal of stubble from the ground is a challenging task, that forces the farmers to burn the residue in-situ. Therefore, accelerated degradation using an eco-friendly alternative is a necessity. White rot fungi are the most explored group of microbes for accelerated degradation of lignin but they are very slow in growth. The present investigation focuses on degradation of rice stubble using a fungal consortium constructed with highly sporulating ascomycetes fungi, namely, Aspergillus terreus, Aspergillus fumigatus and Alternaria spp. All three species were successful at colonizing the rice stubble. Periodical HPLC analysis of rice stubble alkali extracts revealed that incubation with ligninolytic consortium released various lignin degradation products such as vanillin, vanillic acid, coniferyl alcohol, syringic acid and ferulic acid. The efficiency of the consortium was further studied at different dosages on paddy straw. Maximum lignin degradation was observed when the consortium was applied at 15% volume by weight of rice stubble. Maximum activity of different lignolytic enzymes such as lignin peroxidase, laccase and total phenols was also found with the same treatment. FTIR analysis also supported the observed results. Hence, the presently developed consortium for degrading rice stubble was found to be effective in both laboratory and field conditions. The developed consortium or its oxidative enzymes can be used alone or combined with other commercial cellulolytic consortia to manage the accumulating rice stubble effectively.

Following the extraction of essential oil, citrus (Mousambi, Kinnow, and Orange) peel wastes were used to produce pectin. The yield of essential oil and pectin was maximum in orange. Pectin was characterized by Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectroscopy. The degree of esterification (DE) and methoxyl content (MC) was maximum in orange whereas, the equivalent weight was maximum in Mousambi. A significant increase (61.8%) in the Lactobacillus fermentum population was observed with pectin as compared with sugar. Three sources followed the Orange > Kinnow > Mousambi trend as a prebiotic source. It was attributed to higher DE as well as higher MC. Enhancement in the bacterial population was in the range of 79.16–87.50%. The present work confirms the potential of pectin as a probiotic source for the enhancement of the bacterial population. Thus, it has a large scope for use in the food industry targeting a circular economy.

Contrasting tillage and land configuration have important roles in porosity and pore size distribution (PSD), which in turn affects the carbon mineralization in soil. Information on the effects of these treatments on PSD and subsequent carbon mineralization is very limited. Hence, an attempt was made to evaluate the long-term impact of soil tillage and land configurations on the distribution of soil pores and its relationship with soil carbon mineralization under a maize (Zea mays)-wheat (Triticum aestivum) rotation. There were five treatments, that is, conventional tillage, (CT); permanent broad bed, (PBB); PBB + residue (R); zero tillage, (ZT); and ZT + R. Soil pores were quantified by X-ray computed tomography (μ-CT). The conversion of CT to ZT and PBB with or without residue retention (+R) resulted in the reduction of pores >60 μm diameter and was mostly due to a reduction in the number of larger size macro-pores (>110 μm). This resulted in restricted drainage. However, under these practices, pores with larger diameters (60–110 μm) facilitated soil aeration. The total organic carbon (TOC) was 15–48% and 17–47% higher under PBB, PBB + R, ZT, and ZT + R than that under CT in the 0–5 and 5–15 cm layers. The highest MWD (1.01 mm) was in the plots under PBB + R, and the lowest was in the CT plots, and all residue-retained plots (ZT + R and PBB + R) had a higher MWD than residue removal plots (ZT and PBB). Relative to CT, soil C mineralization rates in 0–5 and 5–15 cm soil depths were 63 and 55% higher in the alternate tillage practices, respectively, and the highest value occurred in PPB + R treatments. Increased labile C concentrations were indicative of greater mineralization and were correlated with pores >60 μm, particularly in the size range 110–500 μm and TOC concentrations of 0–15 cm soil layer. Thus, the transition to alternate tillage from the conventional tillage enhanced soil organic carbon concentration (16–47.5%), improved soil structure, reduced the diameter of pores up to >60 μm, and facilitated C mineralization by altering the pore size distribution of soil under a maize-wheat system in the IGP.

The present study aimed to develop nanoemulsions (NEs) of essential oil (EO) and lipid-soluble extract (HE) of Pogostemon cablin leaves using biosurfactant, saponin. Hydro-distilled EO and fat-soluble HE were analyzed using GC-MS, which revealed 38.7 ± 2.7% and 37.5 ± 2.1% patchoulol, respectively. EO and HE were formulated with saponin to prepare corresponding coarse emulsions (CEs); furthermore, high-speed homogenization for 2 min was followed by ultrasonication for 3 min with constant frequency of 50 kHz. of the CEs resulted in respective NEs. NEs were characterized for the physico-chemical properties such as emulsion intrinsic stability, particle size distribution, polydispersity index (PDI), and transmission electron microscopy (TEM) for morphology and accurate nanodroplet diameters. CEs and NEs were investigated for insecticidal efficacy against adults of Tetranychus urticae and larvae of Spodoptera litura. Stable NEs of EO and HE at 500 μg mL−1 concentration exhibited corresponding average particle size of 51.7 and 89.9 nm, while TEM image revealed spherical-shaped droplets with the average droplet diameters of 15.3 and 29.4 nm, respectively. NEs of EO and HE displayed highest efficacy in contact toxicity (LC50 43.2 and 58.4 μg mL−1) after 48 h and fumigant toxicity (LC50 9.3 and 13.6 μg mL−1) after 24 h against T. urticae. In addition, NEs of EO showed considerable antifeedant and feeding deterrent action (AI 99.21 ± 0.74 and FI 99.73 ± 1.24) against S. litura larvae.

A desirable substitute for chemical pesticides is mycopesticides. In the current investigation, rDNA-ITS (Internal transcribed spacer) and TEF (Transcriptional Elongation Factor) sequencing were used for molecular identification of six Beauveria bassiana strains. Both, leaf discs and potted plant bioassaye were carried out to study their pathogenicity against the cassava mite, Tetranychus truncatus. LC50 and LC90 values of potential B. bassiana strains were estimated. We also discovered a correlation between intraspecific B. bassiana strains pathogenicity and comprehensive metabolome profiles. Bb5, Bb6, Bb8, Bb12, Bb15, and Bb21 strains were identified as B. bassiana by sequencing of rDNA-ITS and TEF segments and sequence comparison to NCBI (National Center for Biotechnology Information) GenBank. Out of the six strains tested for pathogenicity, Bb6, Bb12, and Bb15 strains outperformed against T. truncatus with LC50 values 1.4×106, 1.7×106, and 1.4×106 and with a LC90 values 7.3×107, 1.4×108, and 4.2×108 conidia/ml, respectively, at 3 days after inoculation and were considered as potential strains for effective mite control. Later, Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the above six B. bassiana strains was done on secondary metabolites extracted with ethyl acetate revealed that the potential B. bassiana strains (Bb6, Bb12, and Bb15) have higher levels of acaricidal such as Bis(dimethylethyl)-phenol: Bb6 (5.79%), Bb12 (6.15%), and Bb15 (4.69%). Besides, insecticidal (n-Hexadecanoic acid), and insect innate immunity overcoming compound (Nonadecene) were also identified; therefore, the synergistic effect of these compounds might lead toa higher pathogenicity of B. bassiana against T. truncatus. Further, these compounds also exhibited two clusters, which separate the potential and non-potential strains in the dendrogram of Thin Layer Chromatography. These results clearly demonstrated the potentiality of the B. bassiana strains against T. truncatus due to the occurrence of their bioactive volatile metabolome.

Plant growth-promoting endophytic microbes have drawn the attention of researchers owing to their ability to confer fitness benefits in many plant species. Here, we report agriculturally beneficial traits of rice-leaf-adapted endophytic Microbacterium testaceum. Our polyphasic taxonomic investigations revealed its identity as M. testaceum. The bacterium displayed typical endophytism in rice leaves, indicated by the green fluorescence of GFP-tagged M. testaceum in confocal laser scanning microscopy. Furthermore, the bacterium showed mineral solubilization and production of IAA, ammonia, and hydrolytic enzymes. Tobacco leaf infiltration assay confirmed its non-pathogenic nature on plants. The bacterium showed antifungal activity on Magnaporthe oryzae, as exemplified by secreted and volatile organic metabolome-mediated mycelial growth inhibition. GC-MS analysis of the volatilome of M. testaceum indicated the abundance of antimicrobial compounds. Bacterization of rice seedlings showed phenotypic traits of MAMP-triggered immunity (MTI), over-expression of OsNPR1 and OsCERK, and the consequent blast suppressive activity. Strikingly, M. testaceum induced the transcriptional tradeoff between physiological growth and host defense pathways as indicated by up- and downregulated DEGs. Coupled with its plant probiotic features and the defense elicitation activity, the present study paves the way for developing Microbacterium testaceum-mediated bioformulation for sustainably managing rice blast disease.

Di-n-butyl phthalate (DBP) is one of the most extensively used plasticizers for providing elasticity to plastics. Being potentially harmful to humans, investigating eco-benign options for its rapid degradation is imperative. Microbe-mediated DBP mineralization is well-recorded, but studies on the pollutant’s fungal catabolism remain scarce. Thus, the present investigation was undertaken to exploit the fungal strains from toxic sanitary landfill soil for the degradation of DBP. The most efficient isolate, SDBP4, identified on a molecular basis as Aspergillus flavus, was able to mineralize 99.34% dibutyl phthalate (100 mg L−1) within 15 days of incubation. It was found that the high production of esterases by the fungal strain was responsible for the degradation. The strain also exhibited the highest biomass (1615.33 mg L−1) and total soluble protein (261.73 µg mL−1) production amongst other isolates. The DBP degradation pathway scheme was elucidated with the help of GC-MS-based characterizations that revealed the formation of intermediate metabolites such as benzyl-butyl phthalate (BBP), dimethyl-phthalate (DMP), di-iso-butyl-phthalate (DIBP) and phthalic acid (PA). This is the first report of DBP mineralization assisted with A. flavus, using it as a sole carbon source. SDBP4 will be further formulated to develop an eco-benign product for the bioremediation of DBP-contaminated toxic sanitary landfill soils.

Root-knot nematodes belonging to the genus Meloidogyne are agriculturally important pests, and biocontrol strategies offer safer alternatives for their management. In the present study, two fungal species from Indian soils were identified as Arthrobotrys thaumasia and Tolypocladium cylindrosporum based on morphological characteristics and further confirmed using molecular markers. In vitro evaluation of A. thaumasia against M. incognita and Caenorhabditis elegans showed 82 and 73% parasitism, respectively, whereas T. cylindrosporum gave 65.2 and 57.7% parasitism, respectively. Similarly, culture filtrates of A. thaumasia caused 57.7 and 53.7% mortality of M. incognita and C. elegans, respectively, whereas T. cylindrosporum caused higher mortality of 87.3 and 64%, respectively. Besides, greenhouse evaluation of both fungi against M. incognita infecting tomato significantly reduced nematode disease burden reflecting parasitic success measured as the total number of galls, egg masses, eggs per egg mass, and derived nematode multiplication factor. Application of A. thaumasia and T. cylindrosporum reduced nematode multiplication factor by 80 and 95%, respectively, compared with control. General metabolite profiling of tested fungi using gas chromatography–mass spectrometry and ultra-performance liquid chromatography–quadrupole/time of flight mass spectrometry reported for the first time here showed presence of various volatile and non-volatile compounds with nematicidal activity, viz., trimethyl-heptadiene, methyl-hexadecanol, dodecadienal, decane, terpendole E, dodecane, acetamido-6-anthraquinone, and hexadecanol. Also, other compounds such as undecane, dibutyl-disulfide, octadecenal, paganin, talathermophilin, dactylarin, tolypyridone A, tolypyridone B, pyridoxatin, and destruxin were identified, reported in the literature to possess antibacterial, antifungal, and insecticidal properties. This is the first report of the occurrence of both fungi from India and pioneer demonstration of T. cylindrosporum for root-knot nematode management.

Environmental concerns related to synthetic pesticides and the emphasis on the adoption of an integrated pest management concept as a cardinal principle have strengthened the focus of global research and development on botanical pesticides. A scientific understanding of the mode of action of biomolecules over a range of pests is key to the successful development of biopesticides. The present investigation focuses on the in silico protein-ligand interactions of allyl isothiocyanate (AITC), a major constituent of black mustard (Brassica nigra) essential oil (MEO) against two pests, namely, Meloidogyne incognita (Mi) and Fusarium oxysporum f. sp. lycopersici (Fol), that cause severe yield losses in agricultural crops, especially in vegetables. The in vitro bioassay results of MEO against Mi exhibited an exposure time dependent on the lethal concentration causing 50% mortality (LC50) values of 47.7, 30.3, and 20.4 μg ml−1 at 24, 48, and 72 h of exposure, respectively. The study revealed short-term nematostatic activity at lower concentrations, with nematicidal activity at higher concentrations upon prolonged exposure. Black mustard essential oil displayed excellent in vitro Fol mycelial growth inhibition, with an effective concentration to cause 50% inhibition (EC50) value of 6.42 μg ml−1. In order to decipher the mechanism of action of MEO, its major component, AITC (87.6%), which was identified by gas chromatography–mass spectrometry (GC-MS), was subjected to in silico docking and simulation studies against seven and eight putative target proteins of Mi and Fol, respectively. Allyl isothiocyanate exhibited the highest binding affinity with the binding sites of acetyl cholinesterase (AChE), followed by odorant response gene-1 (ODR1) and neuropeptide G-protein coupled receptor (nGPCR) in Mi, suggesting the possible suppression of neurotransmission and chemosensing functions. Among the target proteins of Fol, AITC was the most effective protein in blocking chitin synthase (CS), followed by 2,3-dihydroxy benzoic acid decarboxylase (6m53) and trypsinase (1try), thus inferring these as the principal molecular targets of fungal growth. Taken together, the study establishes the potential of MEO as a novel biopesticide lead, which will be utilized further to manage the Mi–Fol disease complex.

The fungus reported to be a potential antagonist of various soil and seed borne plant pathogens. C. globosum mycoparasitizes and produce antifungal metabolites which suppress the growth of the pathogenic fungi. Despite sufficient knowledge available on secondary metabolites of C. globosum and their wide biological activities, limited literatures are available on the polar active constituents and their potential use as antifungal agent. The study was carried out to evaluate chemical composition of secondary metabolites from C. globosum when it interacts with Bipolaris sorokiniana (2017-2020). The volatile compounds identified through GC-MS revealed that, C. globosum strain Cg2 produced a variety of antifungal secondary metabolites, i.e. octadecene trans-limonene oxide, dodecane, tetracosonal, heptacosanol and octadecanoic acid which may be involved in the antagonism. Similarly, UPLC-QToF-ESIMS analysis of chloroform soluble fraction of C. globosum (Cg2), B. sorokiniana (BS112) and their interaction (Cg2-BS112) were undertaken to identify non-volatile metabolites.These metabolites were identified as Chaetomugilin A, D, E, F, Globoxanthone A, Chaetoviridin A, B, E, Chaetoglobin B, Chaetoquadrin A, Chaetocochin B and F, Chaetoglobosin Q and N.The work indicates that the biocontrol agent C. globosum showed high antifungal metabolite production thereby antagonising B. sorokininana pathogen. The obtained data will greatly enrich current C. globosum metabolomic information and provide a good foundation for better understanding of biocontrol mechanism of C. globosum against plant pathogens and facilitating widespread application in the field of bio-control.

Nematicidal potential of essential oils (EOs) has been widely reported. Terpenoids present in most of the essential oils have been reported responsible for their bioactivity though very less is known about their modes of action. In the present study, an in vitro screening of nine Eos, namely, Citrus sinensis (OEO), Myrtus communis (MTEO), Eucalyptus citriodora (CEO), Melaleuca alternifolia (TEO), Acorus calamus (AEO), Commiphora myrrha (MREO), Cymbopogon nardus (CNEO), Artemisia absinthium (WEO), and Pogostemon cablin (PEO) against Meloidogyne incognita revealed OEO, CNEO, and TEO as most effective with LC50 39.37, 43.22, and 76.28 μg ml–1 respectively. EOs had varying compositions of mono- and sesquiterpenes determined by gas chromatography-mass spectrometry (GC-MS) analysis. The in silico molecular interactions screening of major EO constituents and the seven selected target proteins of the nematode indicated highest binding affinity of geraniol-ODR1 (odorant response gene 1) complex (ΔG = -36.9 kcal mol–1), due to extensive H-bonding, hydrophobic and π-alkyl interactions. The relative binding affinity followed the order: geraniol-ODR1 > β-terpineol-ODR1 > citronellal-ODR1 > l-limonene-ODR1 > γ-terpinene-ODR1. Taken together, the cumulative in vitro and computational bioefficacy analysis related to the chemoprofiles of EOs provides useful leads on harnessing the potential of EOs as bionematicides. The insight on biochemical ligand–target protein interactions described in the present work will be helpful in logical selection of biomolecules and essential oils for development of practically viable bionematicidal products.

Essential oils were obtained from same raw material of cumin seed by extraction with hydrodistillation and super critical fluid extraction (SCFE). For SCFE, supercritical carbon dioxide at 45°C and 100 bar was used as variable for the extraction. The composition of the extracts was determined by gas chromatography-mass spectrometry. Yield of essential oil was more in the SCFE method. Extract obtained by supercritical fluid extraction technique using CO2 was heavier than the hydrodistilled volatile oil. Cumin oil obtained by hydrodistillation contained higher percentage of cuminaldehyde (52.6%), then did oil obtained by SCFE (37.3%), whereas cumin oil obtained by hydrodistillation had the lower percentage of cuminic alcohol (13.3%) as compared to 19.3% in SCFE method. However, cuminal (2-caren-10-al) content was almost similar in cumin oil obtained by the SCFE and hydrodistillation method (24.5–25.8%). Hydrodistilled volatile oil showed better antioxidant activity measured by DPPH and FRAP assay and more total phenol content. The results indicated that though essential oil yield was more in the SCFE method, antioxidant property was more in conventional hydrodistillation method. SCFE extracted non polar (wax materials) compounds along with volatile oil and it was recorded that enhanced aroma of signature compounds of cumin.

Eupatorium adenophorum is commonly known as Crofton weed, growing widely throughout the northern hilly terrains. Bioactive potential of E. adenophorum leaves was investigated through phytochemical study and in vitro plant growth inhibitory. Essential oil was hydrodistilled from leaves and analyzed by GCMS. Leaf material was extracted using cold extraction process followed by evaporation of solvent under reduced pressure. Five cadinene sesquiterpenes and one sterol were isolated from hexane and EtOAc concentrates and their structures were established spectroscopically. Plant growth inhibitory activity of extractives and isolated terpenes were studied against different seeds of weed and crops. Essential oil was moderate seedling growth inhibitor. Among various extracts, EtOAc extract was found to be most inhibitory to Phalaris minor seeds (EC50 117 μg mL-1). Among the sesquiterpenes, 5,6-dihydroxycadinan-3-ene-2,7-dione was found to be most active and inhibited both shoot and root growth of Phalaris minor seed (EC50 97 μg mL-1) and Polygonum plebejum (EC50 117 μg mL-1).