Mungbean Yellow Mosaic India Virus Research Articles

Characterization, phylogeny and recombination of Rhynchosia yellow mosaic virus infecting Rhynchosia minima, a wild relative of pigeonpea (Cajanus cajan) from India.

Rhynchosia minima grown at Indian Institute of Pulses Research, Kanpur, India, showed yellow mosaic symptoms on leaves and were suspected to be caused by begomovirus(es). Leaves from five different plants (Rhm1-Rhm5) were tested for the presence of four viruses in PCR. PCR assays revealed the presence of mungbean yellow mosaic India virus in four samples, whereas one sample (Rhm2) was negative. Processing of Rhm2 sample using rolling circle amplification and restriction digestion indicated the presence of DNA molecules of ~ 2.6-2.7kb. These molecules were sequenced after cloning and found to be of 2741 and 2658 nucleotides in size. BLAST analysis revealed that DNA-A (OQ269467) and DNA-B (OQ269468) molecules of rhynchosia yellow mosaic virus (RhYMV) with 99.09% and 93.74% nucleotide similarity with DNA-A (KP752090) and DNA-B (KP752091) of the RhYMV isolate, respectively. These sequences had a genome organization typical of legume-infecting Old World bipartite begomoviruses. Full genome sequences obtained from Rhm2 are, therefore, considered to be an isolate of RhYMV, designated as RhYMV-IN-Knp. The phylogenetic analysis revealed that RhYMV-IN-Knp was grouped with other isolates of RhYMV followed by Cajanus scarabaeoides yellow mosaic virus. DNA-A of RhYMV-IN-Knp showed two recombination events. The Old World bipartite begomovirus squash leaf curl China virus (AM260205) was identified as the major parent, whereas New World bipartite begomovirus rhynchosia golden yellow mosaic Yucatan virus (EU021216) was identified as the minor parent. RhYMV holds the potential of infecting cultivated legume crops, therefore regular monitoring is crucial especially for pigeonpea breeding programs.

Development of infectious clones of mungbean yellow mosaic India virus (MYMIV, Begomovirus vignaradiataindiaense) infecting mungbean [Vigna radiata (L.) R. Wilczek] and evaluation of a RIL population for MYMIV resistance.

Yellow mosaic disease (YMD) is a major constraint for the low productivity of mungbean, mainly in South Asia. Addressing this issue requires a comprehensive approach, integrating field and challenge inoculation evaluations to identify effective solutions. In this study, an infectious clone of Begomovirus vignaradiataindiaense (MYMIV) was developed to obtain a pure culture of the virus and to confirm resistance in mungbean plants exhibiting resistance under natural field conditions. The infectivity and efficiency of three Agrobacterium tumefaciens strains (EHA105, LBA4404, and GV3101) were evaluated using the susceptible mungbean genotype PS16. Additionally, a recombinant inbred line (RIL) population comprising 175 lines derived from Pusa Baisakhi (MYMIV susceptible) and PMR-1 (MYMIV resistant) cross was developed and assessed for YMD response. Among the tested Agrobacterium tumefaciens strains, EHA105 exhibited the highest infectivity (84.7%), followed by LBA4404 (54.7%) and GV3101 (9.80%). Field resistance was evaluated using the coefficient of infection (CI) and area under disease progress curve (AUDPC), identifying seven RILs with consistent resistant reactions (CI≤9) and low AUDPC (≤190). Upon challenge inoculation, six RILs exhibited resistance, while RIL92 displayed a resistance response, with infection occurring in less than 10% of plants after 24 to 29 days post inoculation (dpi). Despite some plants remaining asymptomatic, MYMIV presence was confirmed through specific PCR amplification of the MYMIV coat protein (AV1) gene. Quantitative PCR revealed a very low relative viral load (0.1-5.1% relative fold change) in asymptomatic RILs and the MYMIV resistant parent (PMR1) compared to the susceptible parent (Pusa Baisakhi). These findings highlight the potential utility of the developed infectious clone and the identified MYMIV-resistant RILs in future mungbean breeding programs aimed at cultivating MYMIV-resistant varieties.

Exploring distribution and genomic diversity of begomoviruses associated with yellow mosaic disease of legume crops from India, highlighting the dominance of mungbean yellow mosaic India virus.

Yellow mosaic disease (YMD) caused by several begomoviruses is one of the major constraints of over a dozen leguminous crops worldwide, particularly in Asian and Southeast Asian countries. The present study aimed to investigate the distribution, diversity and prevalence of begomoviruses associated with YMD in leguminous hosts in five agro-climatic zones of India, to assess the extent of their geographical presence and develop location and crop-specific distribution maps. One hundred and seventy-four leguminous plant samples were tested from 32 locations in India to detect YMD-causing viruses. Additionally, publicly available data were incorporated into this study to provide a comprehensive overview of their distribution in India. This resulted in 581 reports on the DNA-A component representing 119 locations, which were also utilized to depict the distribution of YMD-causing viruses on a map of India. In this study, 117 full-length DNA-A and 103 DNA-B components were successfully characterized, representing the detected mungbean yellow mosaic India virus (MYMIV), mungbean yellow mosaic virus (MYMV), and horsegram yellow mosaic virus in the collected samples. Phylogenetic analysis of isolates of these species showed no differentiation based on location in India. Diversity indices revealed the abundance (55.9%) and dominance (0.56) of MYMIV across 119 locations. These findings hold significant implications for legume researchers, offering insights into disease prevalence and geographic distribution. Furthermore, the distribution of YMD-causing viruses in different agro-climatic zones will help researchers in developing zone-specific YMD-resistant cultivars of the legume crops and would facilitate effective disease management options.

A new isolate of mungbean yellow mosaic India virus in Vigna mungo L. reported from a Dayalbagh field, Agra.

Black gram (Vigna mungo L.) plants showing yellow mosaic symptoms during 2019-2022 crop seasons were collected randomly from a Dayalbagh field, Agra Region of Uttar Pradesh, India. Total genomic DNA was isolated from the infected leaf samples by the Cetyltrimethylammonium bromide (CTAB) method and subjected to PCR. After viral confirmation, the viral genome was amplified by rolling circle amplification following the standard protocol. The DNA A and DNA B subgenomes were cloned individually as a PstI and BamHI fragment in the pUC18 vector. Positive clones were subjected to DNA sequencing. The results revealed that DNA A and DNA B show the closest nucleotide identity with "mungbean yellow mosaic India virus-[Mungbean], DNA-A, the complete sequence" (GeneBank Accession No AF416742.1) with 98.14% identity, and "mungbean yellow mosaic India virus isolate Mu1-Dholi segment DNA-B, the complete sequence" (GeneBank Accession No MW814723.1) with 97.94% identity, respectively. The new isolate of mungbean yellow mosaic India virus (MYMIV) shows sequence similarity with the coat protein gene of various strains of MYMIV. In the new isolate of MYMIV, a point mutation wasobserved at the 2036th nucleotide of DNA B, which disrupts the reading frame to introduce a stop codon and thus leading to a decrease in the size of the movement protein gene. In the present study we are reporting the whole genome sequence of the MYMIV Dayalbagh isolate for the first time.

Identification of mungbean yellow mosaic India virus and susceptibility-related metabolites in the apoplast of mung bean leaves.

The investigation of MYMIV-infected mung bean leaf apoplast revealed viral genome presence, increased EVs secretion, and altered stress-related metabolite composition, providing comprehensive insights into plant-virus interactions. The apoplast, an extracellular space around plant cells, plays a vital role in plant-microbe interactions, influencing signaling, defense, and nutrient transport. While the involvement of apoplast and extracellular vesicles (EVs) in RNA virus infection is documented, the role of the apoplast in plant DNA viruses remains unclear. This study explores the apoplast's role in mungbean yellow mosaic India virus (MYMIV) infection. Our findings demonstrate the presence of MYMIV genomic components in apoplastic fluid, suggesting potential begomovirus cell-to-cell movement via the apoplast. Moreover, MYMIV infection induces increased EVs secretion into the apoplast. NMR-based metabolomics reveals altered metabolic profiles in both apoplast and symplast in response to MYMIV infection, highlighting key metabolites associated with stress and defense mechanisms. The data show an elevation of α- and β-glucose in both apoplast and symplast, suggesting a shift in glucose utilization. Interestingly, this increase in glucose does not contribute to the synthesis of phenolic compounds, potentially influencing the susceptibility of mung bean to MYMIV. Fructose levels increase in the symplast, while apoplastic sucrose levels rise significantly. Symplastic aspartate levels increase, while proline exhibits elevated concentration in the apoplast and reduced concentration in the cytosol, suggesting a role in triggering a hypersensitive response. These findings underscore the critical role of the apoplast in begomovirus infection, providing insights for targeted viral disease management strategies.

Multi-GWAS reveals significant genomic regions for Mungbean yellow mosaic India virus resistance in urdbean (Vigna mungo (L.) across multiple environments.

Unraveling genetic markers for MYMIV resistance in urdbean, with 8 high-confidence marker-trait associations identified across diverse environments, provides crucial insights for combating MYMIV disease, informing future breeding strategies. Globally, yellow mosaic disease (YMD) causes significant yield losses, reaching up to 100% in favorable environments within major urdbean cultivating regions. The introgression of genomic regions conferring resistance into urdbean cultivars is crucial for combating YMD, including resistance against mungbean yellow mosaic India virus (MYMIV). To uncover the genetic basis of MYMIV resistance, we conducted a genome-wide association study (GWAS) using three multi-locus models in 100 diverse urdbean genotypes cultivated across six individual and two combined environments. Leveraging 4538 high-quality single nucleotide polymorphism (SNP) markers, we identified 28 unique significant marker-trait associations (MTAs) for MYMIV resistance, with 8 MTAs considered of high confidence due to detection across multiple GWAS models and/or environments. Notably, 4 out of 28 MTAs were found in proximity to previously reported genomic regions associated with MYMIV resistance in urdbean and mungbean, strengthening our findings and indicating consistent genomic regions for MYMIV resistance. Among the eight highly significant MTAs, one localized on chromosome 6 adjacent to previously identified quantitative trait loci for MYMIV resistance, while the remaining seven were novel. These MTAs contain several genes implicated in disease resistance, including four common ones consistently found across all eight MTAs: receptor-like serine-threonine kinases, E3 ubiquitin-protein ligase, pentatricopeptide repeat, and ankyrin repeats. Previous studies have linked these genes to defense against viral infections across different crops, suggesting their potential for further basic research involving cloning and utilization in breeding programs. This study represents the first GWAS investigation aimed at identifying resistance against MYMIV in urdbean germplasm.

Identification of cowpea [Vigna unguiculata (L.) Walp.] germplasm accessions resistant to yellow mosaic disease

Yellow mosaic disease (YMD) of cowpea, predominantly caused by mungbean yellow mosaic India virus (MYMIV) and mungbean yellow mosaic virus (MYMV) is a major constraint to the production of cowpea (Vigna unguiculata L.) in India resulting in significant yield reductions. The present study extensively evaluated 1127 cowpea germplasm accessions from the National Gene Bank of India, New Delhi, at two hotspot locations (Hyderabad and Delhi) for their response to YMD. About 181 accessions showed no symptoms in field screening at both locations and were considered putatively resistant. A set of the best 100 out of 181 was selected for further confirmation of resistance to MYMIV through whitefly-mediated screening along with 40 accessions known to be susceptible to YMD. The results of whitefly-mediated transmission confirmed MYMIV resistance in 20 accessions with a disease score of zero. Further, the YMD-associated Begomovirus was characterized using rolling circle amplification coupled with sequencing of the full DNA-A genome of MYMIV, which shared an identity of 99.02% with the MYMIV isolate infecting cowpea in Pakistan. The 20 cowpea accessions identified as novel resistant sources to MYMIV in the present study could be used for mapping resistance genes and as donors in resistance breeding for yellow mosaic disease

Emerging evidence of seed transmission of begomoviruses: implications in global circulation and disease outbreak.

Begomoviruses (family Geminiviridae) are known for causing devastating diseases in fruit, fibre, pulse, and vegetable crops throughout the world. Begomoviruses are transmitted in the field exclusively through insect vector whitefly (Bemisia tabaci), and the frequent outbreaks of begomoviruses are attributed largely due to the abundance of whitefly in the agri-ecosystem. Begomoviruses being phloem-borne were known not be transmitted through seeds of the infected plants. The recent findings of seed transmission of begomoviruses brought out a new dimension of begomovirus perpetuation and dissemination. The first convincing evidence of seed transmission of begomoviruses was known in 2015 for sweet potato leaf curl virus followed by several begomoviruses, like bhendi yellow vein mosaic virus, bitter gourd yellow mosaic virus, dolichos yellow mosaic virus, mungbean yellow mosaic virus, mungbean yellow mosaic India virus, pepper yellow leaf curl Indonesia virus, tomato leaf curl New Delhi virus, tomato yellow leaf curl virus, tomato yellow leaf curl Sardinia virus, and okra yellow mosaic Mexico virus. These studies brought out two perspectives of seed-borne nature of begomoviruses: (i) the presence of begomovirus in the seed tissues derived from the infected plants but no expression of disease symptoms in the progeny seedlings and (ii) the seed infection successfully transmitted the virus to cause disease to the progeny seedlings. It seems that the seed transmission of begomovirus is a feature of a specific combination of host-genotype and virus strain, rather than a universal phenomenon. This review comprehensively describes the seed transmitted begomoviruses reported in the last 9 years and the possible mechanism of seed transmission. An emphasis is placed on the experimental results that proved the seed transmission of various begomoviruses, factors affecting seed transmission and impact of begomovirus seed transmission on virus circulation, outbreak of the disease, and management strategies.

Genome organization of satellite DNA beta molecule associated with Mungbean yellow mosaic India virus Gujarat, India

Recent advancements in genomics have unveiled fascinating insights into the intricate world of plant pathogens. The discovery of an intriguing association between the DNA beta and MYMIV-[IN:Ana: CpMBKA25:04], a strain containing 1367 base pairs of nucleotides, has sparked a wave of scientific curiosity. Through sequence identity matrix analysis, it was revealed that this strain shares a striking 96% similarity with the Potato apical leaf curl virus, closely followed by the Tomato leaf curl beta satellite virus [Accession No. AY230138] at 95.3%. In contrast, its relationship with the beta satellite Bhendi yellow vein beta satellite [Accession No. AJ308425] stood at a comparative 45.7% when compared against seventeen other DNA beta isolates infecting various crops. Noteworthy features of the beta satellite sequences include a distinctive putative stem-loop structure TAATATT/AC in the common region and a recurring GCTACGC repeat sequence. An A-rich region spanning from nucleotides 910 to 1120 further adds to the genetic complexity of this novel strain. Intriguingly, an analysis of the amino acid sequence unveiled additional residues V, C, and N at the carboxyl end of the βC1 protein, setting it apart from its counterparts. The identity matrix analysis established a 95.9% similarity between βC1 and the beta satellite associated with Tomato leaf curl Karnataka virus and Potato apical leaf curl virus, phylogenetic analysis placed the beta satellite linked with MYMIV-[IN:Ana: CpMBKA25:04] in a distinct category within the Papaya leaf curl virus family, shedding light on its unique evolutionary lineage and biological significance in the realm of plant virology.

Low-cost water boiling method successfully employed to extract DNA from a single whitefly to detect yellow mosaic disease-causing viruses in PCR

A cost-effective DNA extraction approach was developed and applied to PCR-based identification of yellow mosaic disease (YMD) causing viruses in individual whiteflies. Whiteflies were collected from urdbean and eggplant, representing host and non-host plants of target viruses, respectively. DNA from whiteflies was successfully extracted using the nuclease-free water boiling method and optimised template concentration for PCR assays. An average nucleic acid content of 3.844 ± 0.14 ng/µl was extracted from individual whiteflies in 50 µl nuclease-free water. PCR assays revealed Mungbean yellow mosaic India virus (MYMIV) presence in 90% of the whiteflies collected from urdbean. Conversely, YMD-causing viruses were not present in whiteflies collected from eggplant or in the eggplant plants themselves. The use of this low-cost approach for detecting YMD-causing viruses in whiteflies is very effective for the surveillance and monitoring of viruses. Early detection facilitates the deployment of appropriate management strategies, reducing both crop losses and the potential for outbreaks.

Geographical Distribution and Molecular Characterization of Begomovirus Infecting Soybean [Glycine max (L.) Merr.] in Northern Hills and North Western Plains of India

Background: Yellow mosaic disease (YMD) is one of the most severe and widespread constraint for the cultivation of soybean. Given that no comprehensive data on the status of soybean yellow mosaic disease in Northern Hills and North Western Plains of India is present, a detailed investigation was undertaken for three years to study the prevalence of the disease in the region and to characterize the pathogen. Methods: Towards Kharif end, a three year (2018-2020) farmer field survey (76 villages) was carried out to assess the YMD distribution in the major soybean growing areas Northern Hills and North Western Plains of India. The variability of yellow mosaic virus associated with YMD of soybean was studied based on molecular characterization of partial DNA-A coat protein gene and DNA-B movement protein with subsequent nucleotide sequencing and phylogenetic tree construction. Result: The results revealed that YMD is prevalent in the plains, whereas the disease was undetectable in the Hills. In the plains, the mean disease incidence ranged from 25.40% in 2019 to 16.78% in 2020. Moreover, disease incidence (r = -0.748) had negative and significant (p less than 0.0001) correlation with altitude. The phylogenetic studies revealed that the virus inciting the yellow mosaic in soybean in Tarai region had closest relationship with Mungbean yellow mosaic India virus (MYMIV). It shared more than 96 per cent sequence identity with other MYMIV isolates reported earlier within the country and abroad and hence, was designated as an isolate of MYMIV.

Identification of quantitative trait loci (QTLs) regulating leaf SPAD value and trichome density in mungbean (Vigna radiata L.) using genotyping-by-sequencing (GBS) approach.

Quantitative trait loci (QTL) mapping is used for the precise localization of genomic regions regulating various traits in plants. Two major QTLs regulating Soil Plant Analysis Development (SPAD) value (qSPAD-7-1) and trichome density (qTric-7-2) in mungbean were identified using recombinant inbred line (RIL) populations (PMR-1×Pusa Baisakhi) on chromosome 7. Functional analysis of QTL region identified 35 candidate genes for SPAD value (16 No) and trichome (19 No) traits. The candidate genes regulating trichome density on the dorsal leaf surface of the mungbean include VRADI07G24840, VRADI07G17780, and VRADI07G15650, which encodes for ZFP6, TFs bHLH DNA-binding superfamily protein, and MYB102, respectively. Also, candidate genes having vital roles in chlorophyll biosynthesis are VRADIO7G29860, VRADIO7G29450, and VRADIO7G28520, which encodes for s-adenosyl-L-methionine, FTSHI1 protein, and CRS2-associated factor, respectively. The findings unfolded the opportunity for the development of customized genotypes having high SPAD value and high trichome density having a possible role in yield and mungbean yellow vein mosaic India virus (MYMIV) resistance in mungbean.

Genome-wide association studies for earliness, MYMIV resistance, and other associated traits in mungbean (Vigna radiata L. Wilczek) using genotyping by sequencing approach.

Yellow mosaic disease (YMD) remains a major constraint in mungbean (Vigna radiata (L.)) production; while short-duration genotypes offer multiple crop cycles per year and help in escaping terminal heat stress, especially during summer cultivation. A comprehensive genotyping by sequencing (GBS)-based genome-wide association studies (GWAS) analysis was conducted using 132 diverse mungbean genotypes for traits like flowering time, YMD resistance, soil plant analysis development (SPAD) value, trichome density, and leaf area. The frequency distribution revealed a wide range of values for all the traits. GBS studies identified 31,953 high-quality single nucleotide polymorphism (SNPs) across all 11 mungbean chromosomes and were used for GWAS. Structure analysis revealed the presence of two genetically distinct populations based on ΔK. The linkage disequilibrium (LD) varied throughout the chromosomes and at r2 = 0.2, the mean LD decay was estimated as 39.59 kb. Two statistical models, mixed linear model (MLM) and Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) identified 44 shared SNPs linked with various candidate genes. Notable candidate genes identified include FPA for flowering time (VRADI10G01470; chr. 10), TIR-NBS-LRR for mungbean yellow mosaic India virus (MYMIV) resistance (VRADI09G06940; chr. 9), E3 ubiquitin-protein ligase RIE1 for SPAD value (VRADI07G28100; chr. 11), WRKY family transcription factor for leaf area (VRADI03G06560; chr. 3), and LOB domain-containing protein 21 for trichomes (VRADI06G04290; chr. 6). In-silico validation of candidate genes was done through digital gene expression analysis using Arabidopsis orthologous (compared with Vigna radiata genome). The findings provided valuable insight for marker-assisted breeding aiming for the development of YMD-resistant and early-maturing mungbean varieties.

Molecular characterization of mungbean yellow mosaic India virus infecting Vigna radiata in Oman

AbstractThe full‐genome sequences of a bipartite begomovirus were identified in a mungbean (Vigna radiata) crop displaying symptoms such as yellow mosaics and stunting in the Al‐Batinah North region (23.6867° N 57.9058° E), Oman. Initial detection and confirmation of the virus genome were carried out through polymerase chain reaction, followed by obtaining complete genomes using rolling circle amplification. Bioinformatics analysis on both genomic components, DNA‐A and DNA‐B, revealed over 99% nucleotide sequence identity to the mungbean yellow mosaic India virus (MYMIV), previously known to infect tomato plants. Pairwise sequence analysis using the STD tool and subsequent phylogenetic analysis unveiled that the DNA‐A of the MYMIV isolate formed a cluster with closely related DNA‐A sequences of MYMIV from GenBank, while the DNA‐B clustered with the corresponding DNA‐B of the MYMIV isolate. Additionally, no evidence of recombination events was observed in the recombination analysis. Similarly, the nucleotide substitution rates between the DNA‐A and DNA‐B segments of MYMIV did not show significant differences. This finding represents the first documented instance of bipartite MYMIV infecting V. radiata in Oman.

Resistant Gene Analogue Marker(S) Screening against Yellow Mosaic Disease in Mungbean [Vigna radiata (L.) Wilczek

During Rabi 2021–2022, 100 genotypes of mungbean were tested for resistance to yellow mosaic disease in the field using the disease grading system. Out of the 100 mungbean genotypes, 49 were resistant to the yellow mosaic disease, 22 as Moderately resistant, 11 as Moderately susceptible, 3 as susceptible, and 15 were highly susceptible. The sequenced virus shares 98.94% similarity with the whole coding sequence of the MYMIV-Mb02 coat protein (AV1) gene from the mungbean yellow mosaic India virus strain, accession number GQ387502.1., as per the results of the BLAST program. As a result, the variation was designated mungbean yellow mosaic India virus isolates NAU-RJ coat protein gene segment and assigned the accession number ON622515.1. The current study examined Six resistant (40 C, NMS-21-01, NMS-21-06, NMS-21-22, NMS-21-49, NMS-21-95) and six highly susceptible (GM 4, NMS-21-23, NMS-21-24, NMS-21-40, NMS-21-68, NMS-21-69). In order to identify the six susceptible and six resistant mungbean genotypes, nine pairs of RGA primers were employed. Five pairs of RGA primers were successfully amplified in all resistant genotypes as a consequence, but not in all highly susceptible genotypes. The results of this study suggest that five pairs of RGA markers can effectively distinguish between the genotypes of mungbean that are highly susceptible and resistant. The long-lasting YMV resistance of these RGA markers makes them useful for mapping resistance genes and marker validation studies.

Genetic enhancement for grain yield and mungbean yellow mosaic India virus (MYMIV) resistance through introgressions from Glycine soja

The current study aimed at development of early maturing, mungbean yellow mosaic India virus (MYMIV) resistant and higher yield soybean genotypes. Through a series of backcrosses (BC4 generation) MYMIV resistance gene has been introgressed from G. soja in to a widely adaptable cultivar JS 335. Introgression lines, viz., YMV1, YMV2, YMV 11 and YMV 16 having MYMIV resistance and higher yield performance over recurrent parent and other check varieties were identified and characterized. GGE biplots analysis revealed YMV 16 as ideal genotype with respect to 100-seed weight and grain yield whereas YMV 11 was promising under sugarcane-soybean intercropping system in spring season. Further, study also reports the development of an extra-early maturing (72 days) genetic stock NRC 252, which can be a potential parent in breeding for early maturing soybean varieties. Inconclusion, alleles from wild type soybean could improve yield and MYMIV resistance in cultivated soybean. The genotypes developed in the present study will help in reducing the damage caused by MYMIV disease and area expansion of the soybean crop through intercropping with sugarcane.

Molecular events triggered by Mungbean yellow mosaic India virus infection in blackgram (Vigna mungo (L.) hepper)

Blackgram, one of the most nutritious legume is under constant threat of viral pathogen Mungbean yellow mosaic India virus (MYMIV) causing yield losses of 85–100%. Despite the advances in omics studies, the molecular mechanism associated with viral proliferation and counter resistance thereof, is still not thoroughly understood. The current investigation deciphered transcriptomic dynamics in MYMIV resistant (Mash114) and susceptible blackgram (KUG253) genotypes, in continuation with our previous study on tagging of MYMIV resistance. A total of 10,768 and 19,013 genes were expressed differentially in MYMIV inoculated resistant and susceptible cultivars, respectively. These differentially expressed genes (DEGs) predominantly related to defence mechanism such as protein phosphatise inhibitor, signalling receptor activity, abscisic acid binding, hydrolase activity, and glutathione transferase activity. The genes involved in photosynthesis and ribosomal genes were predominant DEGs among the disease recognition and resistance related DEGs. Beside this hormone induced defence pathway i.e., abscisic acid mediated signaling pathway was enriched by DEGs and could be the plausible mechanism for conferring resistance against MYMIV through restriction of virus by callose deposition at plasmodesmata. Here we identified the four major DEGs i.e. thaumatin like protein, serine threonine protein kinase, putative DNA (cytosine 5) – methyl transferase and chlorophyll a-b binding protein of LHCII type 1-like with putative role in disease resistance against MYMIV, seated in vicinity of previously tagged MYMIV resistance locus on chromosome 6. Chlorophyll a-b binding protein of LHCII type 1-like DEG was aiding viral proliferation in KUG253 with upregulation in susceptible and downregulation in resistant inocultated plants, as compared to its constant expression in uninoculated plants.

Identification of potential sources of mungbean yellow mosaic India virus resistance in black gram (Vigna mungo) and expression of antioxidants and R‐genes modulating resistance response in cultivated and its two wild relatives

AbstractBlack gram is one of the most important short duration grain legume, which contributes significantly towards nutritional security and environmental sustainability. The virus specific primers confirms the presence of mungbean yellow mosaic India virus (MYMIV) in representative samples. A total of 27 cultivated and two wild species were found as highly resistant (HR) to MYMIV and validated through molecular markers. The start codon target (SCoT) markers analysis revealed that the SCoT loci, namely, SCoT‐4 (2200 bp), SCot‐9 (1150/ 1200 bp), SCoT‐15 (1150/1100 bp), SCoT‐16 (700 bp), SCoT‐24 (2500 bp), SCoT‐25 (700 bp), SCoT‐33 (900/1000 bp), and SCoT‐34 (600 bp), were found unique, able to distinguish HR and highly susceptible (HS) genotypes. Biochemical characterization and gene expression profiling revealed the higher expression of antioxidants and R‐genes just after pathogen inoculation indicated the activation of defence mechanism in both cultivated and its wild relatives, which modulates the resistant responses in cultivated and wild accessions. These information will be really helpful in accelerating resistance breeding in black gram.

Exploiting genetic and genomic resources to enhance productivity and abiotic stress adaptation of underutilized pulses.

Underutilized pulses and their wild relatives are typically stress tolerant and their seeds are packed with protein, fibers, minerals, vitamins, and phytochemicals. The consumption of such nutritionally dense legumes together with cereal-based food may promote global food and nutritional security. However, such species are deficient in a few or several desirable domestication traits thereby reducing their agronomic value, requiring further genetic enhancement for developing productive, nutritionally dense, and climate resilient cultivars. This review article considers 13 underutilized pulses and focuses on their germplasm holdings, diversity, crop-wild-crop gene flow, genome sequencing, syntenic relationships, the potential for breeding and transgenic manipulation, and the genetics of agronomic and stress tolerance traits. Recent progress has shown the potential for crop improvement and food security, for example, the genetic basis of stem determinacy and fragrance in moth bean and rice bean, multiple abiotic stress tolerant traits in horse gram and tepary bean, bruchid resistance in lima bean, low neurotoxin in grass pea, and photoperiod induced flowering and anthocyanin accumulation in adzuki bean have been investigated. Advances in introgression breeding to develop elite genetic stocks of grass pea with low β-ODAP (neurotoxin compound), resistance to Mungbean yellow mosaic India virus in black gram using rice bean, and abiotic stress adaptation in common bean, using genes from tepary bean have been carried out. This highlights their potential in wider breeding programs to introduce such traits in locally adapted cultivars. The potential of de-domestication or feralization in the evolution of new variants in these crops are also highlighted.

Evaluation of sowing dates for managing yellow mosaic disease caused by mungbean yellow mosaic India virus in mungbean.

The online version contains supplementary material available at 10.1007/s13205-023-03621-z.