Transcriptome-wide association mapping provides insights into the genetic basis and candidate genes governing flowering, maturity and seed weight in rice bean (Vigna umbellata).

BACKGROUND: Rice bean (Vigna umbellata), an underrated legume, adapts to diverse climatic conditions with the potential to support food and nutritional security worldwide. It is used as a vegetable, minor food crop and a fodder crop, being a rich source of proteins, minerals, and essential fatty acids. However, little effort has been made to decipher the genetic and molecular basis of various useful traits in this crop. Therefore, we considered three economically important traits i.e., flowering, maturity and seed weight of rice bean and identified the associated candidate genes employing an associative transcriptomics approach on 100 diverse genotypes out of 1800 evaluated rice bean accessions from the Indian National Genebank. RESULTS: The transcriptomics-based genotyping of one-hundred diverse rice bean cultivars followed by pre-processing of genotypic data resulted in 49,271 filtered markers. The STRUCTURE, PCA and Neighbor-Joining clustering of 100 genotypes revealed three putative sub-populations. The marker-trait association analysis involving various genome-wide association study (GWAS) models revealed significant association of 82 markers on 48 transcripts for flowering, 26 markers on 22 transcripts for maturity and 22 markers on 21 transcripts for seed weight. The transcript annotation provided information on the putative candidate genes for the considered traits. The candidate genes identified for flowering include HSC80, P-II PsbX, phospholipid-transporting-ATPase-9, pectin-acetylesterase-8 and E3-ubiquitin-protein-ligase-RHG1A. Further, the WRKY1 and DEAD-box-RH27 were found to be associated with seed weight. Furthermore, the associations of PIF3 and pentatricopeptide-repeat-containing-gene with maturity and seed weight, and aldo-keto-reductase with flowering and maturity were revealed. CONCLUSION: This study offers insights into the genetic basis of key agronomic traits in rice bean, including flowering, maturity, and seed weight. The identified markers and associated candidate genes provide valuable resources for future exploration and targeted breeding, aiming to enhance the agronomic performance of rice bean cultivars. Notably, this research represents the first transcriptome-wide association study in pulse crop, uncovering the candidate genes for agronomically useful traits.

Genomic analysis of a spontaneous unifoliate mutant reveals gene candidates associated with compound leaf development in Vigna unguiculata [L] Walp.

Molecular mechanisms which underpin compound leaf development in some legumes have been reported, but there is no previous study on the molecular genetic control of compound leaf formation in Vigna unguiculata (cowpea), an important dryland legume of African origin. In most studied species with compound leaves, class 1 KNOTTED-LIKE HOMEOBOX genes expressed in developing leaf primordia sustain morphogenetic activity, allowing leaf dissection and the development of leaflets. Other genes, such as, SINGLE LEAFLET1 in Medicago truncatula and Trifoliate in Solanum lycopersicum, are also implicated in regulating compound leaf patterning. To set the pace for an in-depth understanding of the genetics of compound leaf development in cowpea, we applied RNA-seq and whole genome shotgun sequence datasets of a spontaneous cowpea unifoliate mutant and its trifoliate wild-type cultivar to conduct comparative reference-based gene expression, de novo genome-wide isoform switch, and genome variant analyses between the two genotypes. Our results suggest that genomic variants upstream of LATE ELONGATED HYPOCOTYL and down-stream of REVEILLE4, BRASSINOSTERIOD INSENSITIVE1 and LATERAL ORGAN BOUNDARIES result in down-regulation of key components of cowpea circadian rhythm central oscillator and brassinosteroid signaling, resulting in unifoliate leaves and brassinosteroid-deficient-like phenotypes. We have stated hypotheses that will guide follow-up studies expected to provide more insights.

Alpha lipoic acid mitigates adverse impacts of drought stress on growth and yield of mungbean: photosynthetic pigments, and antioxidative defense mechanism.

Context: Exogenous use of potential organic compounds through different modes is a promising strategy for the induction of water stress tolerance in crop plants for better yield. Aims: The present study aimed to explore the potential role of alpha-lipoic acid (ALA) in inducing water stress tolerance in mungbean lines when applied exogenously through various modes. Methods: The experiment was conducted in a field with a split-plot arrangement, having three replicates for each treatment. Two irrigation regimes, including normal and reduced irrigation, were applied. The plants allocated to reduced irrigation were watered only at the reproductive stage. Three levels of ALA (0, 0.1, 0.15 mM) were applied through different modes (seed priming, foliar or priming+foliar). Key results: ALA treatment through different modes manifested higher growth under reduced irrigation (water stress) and normal irrigation. Compared to the other two modes, the application of ALA as seed priming was found more effective in ameliorating the adverse impacts of water stress on growth and yield associated with their better content of leaf photosynthetic pigments, maintenance of plant water relations, levels of non-enzymatic antioxidants, improved activities of enzymatic antioxidants, and decreased lipid peroxidation and H2O2 levels. The maximum increase in shoot fresh weight (29% and 28%), shoot dry weight (27% and 24%), 100-grain weight (24% and 23%) and total grain yield (20% and 21%) in water-stressed mungbean plants of line 16003 and 16004, respectively, was recorded due to ALA seed priming than other modes of applications. Conclusions: Conclusively, 0.1 and 0.15 mM levels of ALA as seed priming were found to reduce the adverse impact of water stress on mungbean yield that was associated with improved physio-biochemical mechanisms. Implications: The findings of the study will be helpful for the agriculturalists working in arid and semi-arid regions to obtain a better yield of mungbean that will be helpful to fulfill the food demand in those areas to some extent.

Potassium augments growth, yield, nutrient content, and drought tolerance in mung bean (Vigna radiata L. Wilczek.).

Uneven rainfall and high temperature cause drought in tropical and subtropical regions which is a major challenge to cultivating summer mung bean. Potassium (K), a major essential nutrient of plants can alleviate water stress (WS) tolerance in plants. A field trial was executed under a rainout shelter with additional K fertilization including recommended K fertilizer (RKF) for relieving the harmful impact of drought in response to water use efficiency (WUE), growth, yield attributes, nutrient content, and yield of mung bean at the Regional Agricultural Research Station, BARI, Ishwardi, Pabna in two successive summer season of 2018 and 2019. Drought-tolerant genotype BMX-08010-2 (G1) and drought-susceptible cultivar BARI Mung-1 (G2) were grown by applying seven K fertilizer levels (KL) using a split-plot design with three replications, where mung bean genotypes were allotted in the main plots, and KL were assigned randomly in the sub-plots. A considerable variation was observed in the measured variables. Depending on the different applied KL and seed yield of mung bean, the water use efficiency (WUE) varied from 4.73 to 8.14 kg ha-1 mm-1. The treatment applying 125% more K with RKF (KL7) under WS gave the maximum WUE (8.14 kg ha-1 mm-1) obtaining a seed yield of 1093.60 kg ha-1. The treatment receiving only RKF under WS (KL2) provided the minimum WUE (4.73 kg ha-1 mm-1) attaining a seed yield of 825.17 kg ha-1. Results showed that various characteristics including nutrients (N, P, K, and S) content in stover and seed, total dry matter (TDM) in different growth stages, leaf area index (LAI), crop growth rate (CGR), root volume (RV), root density (RD), plant height, pod plant-1, pod length, seeds pod-1, seed weight, and seed yield in all pickings increased with increasing K levels, particularly noted with KL7. The highest grain yield (32.52%) was also obtained from KL7 compared to lower K with RKF. Overall, yield varied from 1410.37 kg ha-1 using 281 mm water (KL1; well-watered condition with RKF) to 825.17 kg ha-1 using 175 mm water (KL2). The results exhibited that the application of additional K improves the performance of all traits under WS conditions. Therefore, mung beans cultivating under WS requires additional K to diminish the negative effect of drought, and adequate use of K contributes to accomplishing sustainable productivity.

Microencapsulation of ginger essential oil using mung bean protein isolate-chitosan complex coacervates: Application in the preservation of crab meatballs and the prediction of shelf life.

Crab meatballs with more unsaturated fat tend to spoil. Ginger essential oil (GEO) with oxidation resistance was encapsulated into microcapsules (GM) by complex cohesion of mung bean protein isolate (MBPI) and chitosan (CS) in a ratio of 8:1 at pH = 6.4, encapsulation efficiency (EE) and payload (PL) of GM (D50 = 26.16 ± 0.45 µm) with high thermal stability were 78.35 ± 1.02% and 55.43 ± 0.64%. GM (0.6%, w/w) did not interfere with the original flavor of crab meatballs, and lowered values of pH, thiobarbituric acid reactive substances (TBARS) and total bacteria counts (TBC) of the products than those spiked with GEO and the control. The prediction accuracy of the logistic first-order growth kinetic equation in line with TBC (2.84%) was better than that of zero-order and Arrhenius coupled equation based on pH (7.48%) and TBARS (5.94%), but all of them could predict the shelf life of crab meatballs containing GM stored at 4-25 °C.

Hollow Mesoporous Silica Nanoparticles as a New Nanoscale Resistance Inducer for Fusarium Wilt Control: Size Effects and Mechanism of Action.

In agriculture, soil-borne fungal pathogens, especially Fusarium oxysporum strains, are posing a serious threat to efforts to achieve global food security. In the search for safer agrochemicals, silica nanoparticles (SiO2NPs) have recently been proposed as a new tool to alleviate pathogen damage including Fusarium wilt. Hollow mesoporous silica nanoparticles (HMSNs), a unique class of SiO2NPs, have been widely accepted as desirable carriers for pesticides. However, their roles in enhancing disease resistance in plants and the specific mechanism remain unknown. In this study, three sizes of HMSNs (19, 96, and 406 nm as HMSNs-19, HMSNs-96, and HMSNs-406, respectively) were synthesized and characterized to determine their effects on seed germination, seedling growth, and Fusarium oxysporum f. sp. phaseoli (FOP) suppression. The three HMSNs exhibited no side effects on cowpea seed germination and seedling growth at concentrations ranging from 100 to 1500 mg/L. The inhibitory effects of the three HMSNs on FOP mycelial growth were very weak, showing inhibition ratios of less than 20% even at 2000 mg/L. Foliar application of HMSNs, however, was demonstrated to reduce the FOP severity in cowpea roots in a size- and concentration-dependent manner. The three HMSNs at a low concentration of 100 mg/L, as well as HMSNs-19 at a high concentration of 1000 mg/L, were observed to have little effect on alleviating the disease incidence. HMSNs-406 were most effective at a concentration of 1000 mg/L, showing an up to 40.00% decline in the disease severity with significant growth-promoting effects on cowpea plants. Moreover, foliar application of HMSNs-406 (1000 mg/L) increased the salicylic acid (SA) content in cowpea roots by 4.3-fold, as well as the expression levels of SA marker genes of PR-1 (by 1.97-fold) and PR-5 (by 9.38-fold), and its receptor gene of NPR-1 (by 1.62-fold), as compared with the FOP infected control plants. Meanwhile, another resistance-related gene of PAL was also upregulated by 8.54-fold. Three defense-responsive enzymes of POD, PAL, and PPO were also involved in the HMSNs-enhanced disease resistance in cowpea roots, with varying degrees of reduction in activity. These results provide substantial evidence that HMSNs exert their Fusarium wilt suppression in cowpea plants by activating SA-dependent SAR (systemic acquired resistance) responses rather than directly suppressing FOP growth. Overall, for the first time, our results indicate a new role of HMSNs as a potent resistance inducer to serve as a low-cost, highly efficient, safe and sustainable alternative for plant disease protection.

Enhanced Physiological and Biochemical Performance of Mung Bean and Maize under Saline and Heavy Metal Stress through Application of Endophytic Fungal Strain SL3 and Exogenous IAA.

Modern irrigation practices and industrial pollution can contribute to the simultaneous occurrence of salinity and heavy metal contamination in large areas of the world, resulting in significant negative effects on crop productivity and sustainability. This study aimed to investigate the growth-promoting potentials of an important endophytic fungal strain SL3 and to compare its potential with exogenous IAA (indole-3-acetic acid) in the context of salt and heavy metal stress. The strain was assessed for plant growth-promoting traits such as the production of indole-3-acetic acid, gibberellins (GA), and siderophore. We selected two important crops, mung bean and maize, and examined various physiological and biochemical characteristics under 300 mM NaCl and 2.5 mM Pb stress conditions, with and without the application of IAA and SL3. This study's results demonstrated that both IAA and SL3 positively impacted the growth and development of plants under normal and stressed conditions. In NaCl and Pb-induced stress conditions, the growth of mung bean and maize plants was significantly reduced. However, the application of IAA and SL3 helped to alleviate stress, leading to a significant increase in shoot/root length and weight compared to IAA and SL3 non-treated plants. The results revealed that photosynthetic pigments, accumulation of catalase (CAT), phenolic contents, polyphenol oxidase, and flavanols are higher in the IAA and SL3-treated plants than in the non-inoculated plants. This study's findings revealed that applying the SL3 fungal strain positively influenced various physiological and biochemical processes in tested plant species under normal and stress conditions of NaCl and Pb. These findings also suggested that SL3 could be a potential replacement for widely used IAA to promote plant growth by improving photosynthetic efficiency, reducing oxidative stress, and enhancing metabolic activities in plants, including mung and maize. Moreover, this study highlights that SL3 has synergistic effects with IAA in enhancing resilience to salt and heavy stress and offers a promising avenue for future agricultural applications in salt and heavy metal-affected regions.

Antifungal potential of Streptomyces rameus GgS 48 against mungbean root rot [Rhizoctonia bataticola (Taub.) Butler].

Mungbean root rot caused by Rhizoctonia bataticola (Taub.) Butler is the most devastating disease inflicting yield loss up to 60%. The use of beneficial antagonist, viz., Streptomyces with diverse antifungal activity and prolific secondary metabolites production, is the ecofriendly and environmentally acceptable alternative to the existing chemical control methods. In this investigation we have identified the promising isolate of Streptomyces sp. which potentially reduced the mungbean root rot. A total of nine mungbean rhizospheric actinobacterial isolates were evaluated for their antagonistic potential against root rot pathogen and growth promoting trait of mungbean. The actinobacterial isolate GgS 48 was shown to be effective in reducing the mycelial growth of R. bataticola by 65.3% in dual culture technique and enhancing the growth of mugbean under in vitro condition. Morphological, biochemical and molecular characterization confirmed the isolate GgS 48 as Streptomyces rameus. The actinobacteria S. rameus GgS 48 exerted antifungal action against R. bataticola by hyphal coiling, which was confirmed under scanning electron microscopy (SEM), and promoted the growth through the production of IAA. It showed positive for the production of siderophore and hydrolytic enzymes, viz., chitinase and protease. The chitinase produced by the GgS 48 was purified and its molecular weight was determined as 40 kDa and it had great potential in reducing the mycelial growth of R. bataticola. The talc-based formulation of S. rameus GgS 48 was found to be promising in suppressing the root rot severity and enhancing the growth and yield attributes of mungbean both under glass house and field conditions.

Screening of cowpea (Vigna unguiculata (L.) Walp.) genotypes for waterlogging tolerance using morpho-physiological traits at early growth stage.

The majority of cowpea (Vigna unguiculata (L.) Walp.) produced in the U.S. is planted shortly after the summer rains and subsequently depends on rain or artificial irrigation. Therefore, excessive precipitation and poor soil drainage will cause cowpea plants to suffer temporary waterlogging, reducing the submerged tissue's oxygen level. Although cowpea is sensitive to waterlogging, excessive moisture can induce several morpho-physiological changes with adverse impacts on yield in its early stages of development. The current study subjected 30 cowpea genotypes to 10-days of waterlogging at the seedling stage under a controlled environment. The dynamic changes of 24 morpho-physiological parameters under waterlogging and optimal water conditions were analyzed to understand cowpea's response to waterlogging. Significant waterlogging treatment, cowpea genotypes, and their interactions (P < 0.001) were observed for most of the measured parameters. The results indicated that plant height (PH), leaf area (LA), fresh (FW) and dry weight (DW) of cowpea genotypes were significantly decreased under waterlogging compared to the control treatments. Similar results were obtained for net photosynthesis (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (E). However, the water use efficiency (WUE) and adventitious roots (ARs) increased linearly under waterlogging conditions. Waterlogging also declined chlorophyll fluorescence parameters except non-photochemical quenching (qN), which increased with excess soil moisture. In addition, waterlogging tolerance coefficient (WTC) and multivariate analysis (MCA) methods were used to characterize cowpea genotypes for waterlogging tolerance. Accordingly, the cowpea genotype Dagupan Pangasinan, UCR 369, and Negro were classified as waterlogging tolerant, while EpicSelect.4 and ICARDA 140071, as the most waterlogging sensitive. The cowpea genotypes and morpho-physiological traits determined from this study may be useful for genetic engineering and breeding programs that integrate cowpea waterlogging tolerance.

Path-coefficient and correlation analysis in Bambara groundnut (Vigna subterranea [L.] Verdc.) accessions over environments.

In a breeding program, studies of genotypic and phenotypic relationships among agricultural crop traits are useful to design, evaluate, and develop selection criteria for desirable traits. Using path coefficient analysis, the present study was executed to estimate the phenotypic, genotypic, and environmental correlation coefficients between yield and yield-related traits and to determine the direct and indirect effects of yield-related traits on yield per plant. A total of 30 genotypes of Vigna subterranea were studied under tropical conditions at two sites over two planting seasons (considered as four environments). The experiment at each site used a randomized complete block design with three replicates. Data were collected on vegetative and yield component attributes. Based on analysis of variance, pooled results showed that there were positive and highly significant differences (p ≤ 0.01) among the 30 genotypes for all attributes studied. Highly significant and positive strong correlation at phenotypic level was observed for dry seed weight (0.856), hundred seed weight (0.754), fresh pod weight (0.789), and total pod weight (0.626) with yield in kg per hectare, while moderate positive correlations were observed for harvest cut (0.360) and days to maturity (0.356). However, a perfect positive correlation was observed for the dry weight of pods with seed yield. In contrast, days to 50% flowering (- 0.350) showed a negative significant relationship with yield per hectare. The dried pod weight attribute (1.00) had a high positive direct effect on yield. Fresh pod weight had the greatest indirect effect on yield per hectare, followed by the number of total pods by dry pod weight. As a result, dry pod weight, hundred seed weight, number of total pods, and fresh pod weight could be used as selection criteria to improve the seed yield of Bambara groundnut (Vigna subterranea).

Cloning, Characterization, Expression Analysis, and Agglutination Studies of Novel Gene Encoding ß-D-Galactose, N-Acetyl-D-Glucosamine and Lactose-Binding Lectin from Rice Bean (Vigna umbellata).

Lectins are glycoproteins and known for their peculiar carbohydrate-binding activity and their insect-pest-resistant properties. Earlier we have published our research finding on novel gene encoding Bowman-Birk type protease inhibitor with insecticidal properties from rice bean. This paper presents first report on cloning, sequencing, and expression of RbL ORF of 843 bp encoding 280 amino acids long lectin precursor from rice bean (Vigna umbellata) seeds. Blast analysis revealed more than 90% similarity of RbL protein with Vigna aconitifolia and Vigna angularis lectins. Phylogenetic analysis also revealed a close relationship between RbL and other legume lectins. Sequence analysis of genomic DNA revealed intronless nature of RbL gene (GenBank accession No. MT043160). The isolated RbL ORF was expressed in E. coli BL-21(DE3) cells and maximum expression was recorded with 0.5 mM IPTG after 4 h incubation at 37 °C. Western blotting confirmed RbL protein expression in E. coli. Recombinant protein (His6-RbL) of ~ 35 kDa m.wt was purified using Ni-NTA affinity chromatography to the extent of 0.26 mg/ml. In silico analysis characterized RbL protein as acidic, stable, hydrophobic, and secretary protein with one signal peptide cleavage site (A26-A27) and four N-glycosylation sites. Template-based 3D model of RbL was structured using MODELLER tool and validated as good quality model. Structural analysis revealed dominance of ß-pleated sheets and ß-turns in RbL protein structure. ß-D-galactose, N-acetyl-D-glucosamine, and lactose were predicted as putative ligands for RbL protein. Hydrogen bonding and hydrophobic forces were the major interactions between the predicted ligands and RbL protein. Agglutination and agglutination inhibition assays confirmed the binding specificity of RbL protein with the trypsinized rabbit erythrocytes and with the predicted ligands, respectively. Gene ontology analysis functionally annotated RbL protein as a plant defense protein. The novel information generated in the study is not mere pre-experimental findings but could also lay foundation for future research on exploring RbL gene and encoding protein for different biomedical and biotechnological applications.

Selenium-agarose hybrid hydrogel as a recyclable natural substrate for selenium-enriched cultivation of mung bean sprouts.

Selenium (Se) is an essential trace element for human beings and animals. Traditional plant Se enrichment technology suffers from selenium pollution. Herein, environmentally friendly Se-agarose (Se-Agar) hybrid hydrogels are prepared by simply mixing agar with different Se species including selenocarrageenan (SeCA), selenite and Se yeast under heating and stirring for 0.5 h without any other reagent. Such Se-Agar hybrid hydrogels with excellent biocompatibility were used as natural substrates for the cultivation of Se-enriched mung bean sprouts. Compared with Se yeast, SeCA and selenite show a better Se enrichment effect on mung bean sprouts. Furthermore, the growth indices including plant weight and plant height of mung bean sprouts were investigated with different concentrations and sources of Se. Notably, the Se-Agar hybrid hydrogels could be easily regenerated and reused for multiple cycles. The results indicated that Se-Agar hybrid hydrogels as recyclable natural substrates offer a simple, sustainable and affordable strategy for plant Se enrichment.

Phyto-complexation of galactomannan-stabilized calcium hydroxide and selenium-calcium hydroxide nanocomposite to enhance the seed-priming effect in Vigna radiata.

The evaluation of nano-priming effect with galactomannan stabilized Phyto-complexed calcium hydroxide (Ca(OH)2), selenium oxyanion­calcium hydroxide SeO-(Ca(OH)2), and selenium­calcium hydroxide Se-(Ca(OH)2) nanocomposites was carried out in Vigna radiata (Green gram) seeds. The green source Cassia angustifolia seed rich in galactomannan and other phytoconstituents was detected experimentally and characterized with GC-MS, UV, FT-IR, NMR, XRD, and SEM studies. The highly active galactomannan and other biomolecules, enable their terminal oxygen and hydroxide groups to bind with calcium and selenium ions through bidentate and monodentate chelation, followed by bio-reduction. On the mild-thermal agitation, bio-stabilized (Ca(OH)2), SeO-(Ca(OH)2), and Se-(Ca(OH)2) nanocomposite coated with seed-derived biomolecules were precipitated under an alkaline condition. The size and morphological parameters of bio-fabricated nanocomposites were characterized to exhibit the spherical and hexagonal shape in nanoscale images of size 17.9 nm for (Ca(OH)2), 56.2 nm for SeO-(Ca(OH)2), and 69.3 nm Se-(Ca(OH)2). The sub-standard seed lot of Vigna radiata (Green gram) seeds (71%) was examined using synthesized nanocomposites at various concentrations, and the obtained physiological parameters in seedlings were compared with hydro-primed seeds. The nano-priming action of all the Phyto-complexed nanocomposites was predicted with a positive response, where the porous Se-(Ca(OH)2) possess high efficacy interaction on seed embryos and beneficially results at 90% germination.

Effect of cowpea (Vigna unguiculata L. Walp) sowing season on population dynamics of pest insects

Several factors limit cowpea quality and yield, such as the choice of a cultivar better adapted to the region, the ideal sowing season, as well as diseases and pests. Aimed to evaluate the effect of different sowing seasons on the population dynamics of pest insects of cowpea crops. The study was carried out during the dry season, the rainy season, and the season recommended for sowing by the Experimental Farm of the Federal University of Amazonas (FAEXP­UFAM), Brazil. A total of 33 weekly collections were carried out during the three sowing seasons, distributed in two ways according to the phenological stage of the crop: manual collection per linear meter of plantation and entomological scanning net. The faunistic analysis detected the pest insects Acromyrmex laticeps nigrosetosus, Cerotoma arcuata, Crinocerus sanctus, Euschistus heros, Horciasinus signoreti, Liriomyza sativae, and Nezara viridula. Of these species, H. signoreti stands out for being recorded for the first time as predominant in cowpea crops in the Brazilian state of Amazonas. Infections by hemipterans such as C. sanctus, E. heros, H. signoreti, and N. viridula were detected throughout the study, regardless of the sowing season, except for H. signoreti, which was dominant in all three seasons. The highest infestation of C. arcuata occurred during the recommended sowing season for cowpeas (June to August). According to the Jaccard index, plantation I e II share 86% of the species. This study provides important information to programs in insect control and management and to the agronomic decision-making process.

AMMI and GGE biplot analysis for yield performance and stability assessment of selected Bambara groundnut (Vigna subterranea L. Verdc.) genotypes under the multi-environmental trails (METs).

The stability and high yielding of Vigna subterranea L. Verdc. genotype is an important factor for long-term development and food security. The effects of G × E interaction on yield stability in 30 Bambara groundnut genotypes in four different Malaysian environments were investigated in this research. The experiment used a randomized complete block design with three replications in each environment. Over multiple harvests, yield component traits such as the total number of pods per plant, fresh pods weight (g), hundred seeds weight (g), and yield per hectare were evaluated in the main and off-season in 2020 and 2021. Stability tests for multivariate stability parameters were performed based on analyses of variance. For all the traits, the pooled analysis of variance revealed highly significant (p < 0.01) variations between genotypes, locations, seasons, and genotypes by environment (G × E interaction). A two-dimensional GGE biplot was generated using the first two principal components (axis 1 and axis 2), which accounted for 94.97% and 3.11% difference in GEI for yield per hectare, respectively. Season and location were found to be the most significant causes of yield heterogeneity, accounting for 31.13% and 14.02% of overall G + E + G × E variation, respectively, according to the combined study of variance. The GGE biplot revealed that the three winning genotypes G1, G3, and G5 appear across environments whereas AMMI model exposed genotypes viz G18, G14, G7, G3, G1, and G5 as best performer. Based on ideal genotype ranking genotype G1 was the best performer, with a high mean yield and high stability in the tested environment. According to the AEC line, genotypes G1 and G3 were extremely stable, while genotypes G2 and G4 were low stable, with a high average yielding per hectare. A GGE and AMMI biplot graphically showed the interrelationships between the tested environment and genotypes, classified genotypes into three categories as well as simplifying visual evaluations, according to this investigation. According to our results, breeding could improve yield production, and the genotypes discovered could be recommended for commercial cultivation.

Nitrogen fertilization impact on soil carbon pools and their stratification and lability in subtropical wheat-mungbean-rice agroecosystems.

Nitrogen (N) is the prime nutrient for crop production and carbon-based functions associated with soil quality. The objective of our study (2012 to 2019) was to evaluate the impact of variable rates of N fertilization on soil organic carbon (C) pools and their stocks, stratification, and lability in subtropical wheat (Triticum aestivum)-mungbean (Vigna radiata)-rice (Oryza sativa L) agroecosystems. The field experiment was conducted in a randomized complete block design (RCB) with N fertilization at 60, 80, 100, 120, and 140% of the recommended rates of wheat (100 kg/ha), mungbean (20 kg/ha), and rice (80 kg/ha), respectively. Composite soils were collected at 0-15 and 15-30 cm depths from each replicated plot and analyzed for microbial biomass (MBC), basal respiration (BR), total organic C (TOC), particulate organic C (POC), permanganate oxidizable C (POXC), carbon lability indices, and stratification. N fertilization (120 and 140%) significantly increased the POC at both depths; however, the effect was more pronounced in the surface layer. Moreover, N fertilization (at 120% and 140%) significantly increased the TOC and labile C pools when compared to the control (100%) and the lower rates (60 and 80%). N fertilization significantly increased MBC, C pool (CPI), lability (CLI), and management indices (CMI), indicating improved and efficient soil biological activities in such systems. The MBC and POC stocks were significantly higher with higher rates of N fertilization (120% and 140%) than the control. Likewise, higher rates of N fertilization significantly increased the stocks of labile C pools. Equally, the stratification values for POC, MBC, and POXC show evidence of improved soil quality because of optimum N fertilization (120-140%) to maintain and/or improve soil quality under rice-based systems in subtropical climates.

Acclimation of cadmium-induced genotoxicity and oxidative stress in mung bean seedlings by priming effect of phytohormones and proline.

In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 µM), salicylic acid (SA) (50 µM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.

Disparate genetic variants associated with distinct components of cowpea resistance to the seed beetle Callosobruchus maculatus.

KEY MESSAGE: Polygenic genome-wide association mapping identified two regions of the cowpea genome associated with different components of resistance to its major post-harvest pest, the seed beetle Callosobruchus maculatus. Cowpea (Vigna unguiculata) is an important grain and fodder crop in arid and semi-arid regions of Africa, Asia, and South America, where the cowpea seed beetle, Callosobruchus maculatus, is a serious post-harvest pest. Development of cultivars resistant to C. maculatus population growth in storage could increase grain yield and quality and reduce reliance on insecticides. Here, we use a MAGIC (multi-parent, advanced-generation intercross) population of cowpea consisting of 305 recombinant inbred lines (RILs) to identify genetic variants associated with resistance to seed beetles. Because inferences regarding the genetic basis of resistance may depend on the source of the pest or the assay protocol, we used two divergent geographic populations of C. maculatus and two complementary assays to measure several aspects of resistance. Using polygenic genome-wide association mapping models, we found that the cowpea RILs harbor substantial additive-genetic variation for most resistance measures. Variation in several components of resistance, including larval development time and survival, was largely explained by one or several linked loci on chromosome 5. A second region on chromosome 8 explained increased seed resistance via the induction of early-exiting larvae. Neither of these regions contained genes previously associated with resistance to insects that infest grain legumes. We found some evidence of gene-gene interactions affecting resistance, but epistasis did not contribute substantially to resistance variation in this mapping population. The combination of mostly high heritabilities and a relatively consistent and simple genetic architecture increases the feasibility of breeding for enhanced resistance to C. maculatus.

Biotransformation of Reactive Red 141 by Paenibacillus terrigena KKW2-005 and Examination of Product Toxicity.

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40°C. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N1-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.

Zinc biofortification potential of diverse mungbean [Vigna radiata (L.) Wilczek] genotypes under field conditions.

Zinc (Zn) is an important micronutrient for crop plants and essential for human health. The Zn-deficiency is an important malnutrition problem known globally. Biofortified foods could overcome Zn deficiency in humans. Mungbean [Vigna radiata (L.) Wilczek] is an important, pulse crop frequently grown in arid and semi-arid regions of the world. Mungbean could provide essential micronutrients, including Zn to humans. Therefore, it is very important to investigate the impact of Zn fertilization on the yield and grain biofortification of mungbean. Twelve mungbean genotypes (i.e., NM-28, NM-2011, NM-13-1, NM-2006, NM-51, NM-54, NM-19-19, NM-92, NM-121-25, NM-20-21, 7006, 7008) were assessed for their genetic diversity followed by Zn-biofortification, growth and yield under control (0 kg ha-1) and Zn-fertilized (10 kg ha-1) conditions. Data relating to allometric traits, yield components, grain yield and grain Zn contents were recorded. Zinc fertilization improved entire allometric and yield-related traits. Grain yield of different genotypes ranged from 439 to 904 kg ha-1 under control and 536 to 1462 kg ha-1 under Zn-fertilization. Zinc concentration in the grains varied from 15.50 to 45.60 mg kg-1 under control and 18.53 to 64.23 mg kg-1 under Zn-fertilized conditions. The tested genotypes differed in their Zn-biofortification potential. The highest and the lowest grain Zn contents were noted for genotypes NM-28 and NM-121-25, respectively. Significant variation in yield and Zn-biofortification indicated the potential for improvement in mungbean yield and grain Zn-biofortification. The genotypes NM-28 and NM-2006 could be used in breeding programs for improvement in grain Zn concentration due to their high Zn uptake potential. Nonetheless, all available genotypes in the country should be screened for their Zn-biofortification potential.