Mungbean Yellow Mosaic India Virus Research Articles

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.

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.

Field and agroinoculation screening of national collection of urd bean (Vigna mungo) germplasm accessions for new sources of mung bean yellow mosaic virus (MYMV) resistance.

Yellow mosaic disease (YMD) is a major problem in Urd bean (Vigna mungo L.) in India, which causes huge yield losses. Breeding for wide spectrum and durable Mungbean yellow mosaic virus (MYMV) resistance and cultivating resistant cultivars is the most appropriate and effective approach. However, the task has become challenging with the report of at least two species of the virus, viz., Mungbean yellow mosaic virus (MYMV) and Mungbean yellow mosaic India virus (MYMIV) and their recombinants; the existence of various isolates of these species with varied virulence and rapid mutations noted in the virus as well as in the whitefly vector population. Thus the present study was carried out to identify and characterize novel and diverse sources of YMV resistance and develop linked molecular markers for breeding durable and broadspectrum resistant urdbean cultivars against YMV. Towards this goal, we have screened 998 accessions of urdbean national collection of germplasm against YMD Hyderabad isolate both in a field under the natural level of disease incidence and through agro inoculation in the laboratory using viruliferous clones of the same isolate. Ten highly resistant accessions identified through repeated testing have been characterized in terms of reported linked markers. We attempted to see diversity among the ten resistant accessions reported here using earlier reported resistance-linked SCAR marker YMV1 and SSR CEDG180 marker. SCAR marker YMV1 did not amplify with any of the 10 accessions. But with CEDG180, results suggested that 10 accessions shortlisted through field and laboratory tests do not carry PU31 allele and this shows that it may be likely to carry novel gene(s). Further studies are needed to genetically characterize these new sources.

Deciphering the role of alternative splicing as modulators of defense response in the MYMIV- Vigna mungo pathosystem.

Alternative splicing (AS) is a crucial regulatory mechanism that impacts transcriptome and proteome complexity under stressful situations. Although its role in abiotic stresses is somewhat understood, our understanding of the mechanistic regulation of pre-mRNA splicing in plant-pathogen interaction is meagre. To comprehend this unexplored immune reprogramming mechanism, transcriptome profiles of Mungbean Yellow Mosaic India Virus (MYMIV)-resistant and susceptible Vigna mungo genotypes were analysed for AS genes that may underlie the resistance mechanism. Results revealed a repertoire of AS-isoforms accumulated during pathogenic infestation, with intron retention being the most common AS mechanism. Identification of 688 differential alternatively spliced (DAS) genes in the resistant host elucidates its robust antiviral response, whereas 322 DAS genes were identified in the susceptible host. Enrichment analyses confirmed DAS transcripts pertaining to stress, signalling, and immune system pathways have undergone maximal perturbations. Additionally, a strong regulation of the splicing factors has been observed both at transcriptional and post-transcriptional levels. qPCR validation of candidate DAS transcripts with induced expression upon MYMIV-infection demonstrated a competent immune response in the resistant background. The AS-impacted genes resulted either in partial/complete loss of functional domains or altered sensitivity to miRNA-mediated gene silencing. A complex regulatory module, miR7517-ATAF2, has been identified in an aberrantly spliced ATAF2 isoform that exposes an intronic miR7517 binding site, thereby suppressing the negative regulator to enhance defense reaction. The present study establishes AS as a non-canonical immune reprogramming mechanism that operates in parallel, thereby offering an alternative strategy for developing yellow mosaic-resistant V. mungo cultivars. This article is protected by copyright. All rights reserved.

Development of Specific Detection for Mungbean Yellow Mosaic India Virus Infecting Yard Long Bean in Java, Indonesia

Yellow mosaic disease was reported for the first time in Indonesia in 2008. Its infection on yard long bean caused significant yield loss. Mungbean yellow mosaic India virus (MYMIV), member of genus Begomovirus was identified as the main causal agent. Specific and accurate detection is important for disease monitoring as part of disease management strategy. The aim of this study was to construct specific primer pairs for quick and robust detection of MYMIV using polymerase chain reaction method. A pair of primers MY1/MY2 was designed in this study to amplify part of MYMIV coat protein. In silico and in vitro test showed that MY1/MY2 primers specifically amplified MYMIV.

Molecular Epidemiology of Begomoviruses Infecting Mungbean from Yellow Mosaic Disease Hotspot Regions of India.

The major threat to mungbean (Vigna radiata L.) cultivation in the Indian subcontinent is yellow mosaic diseases (YMD), caused by Begomovirus containing bipartite genomes (DNA-A and DNA-B). In the current study, we address the epidemiology of begomoviruses infecting mungbean plants in three YMD hotspot regions of India. Full-length genomic components of the viruses from the symptomatic leaves were cloned by rolling circle amplification (RCA) and sequenced. Mungbean yellow mosaic virus (MYMV) was detected in Bihar and mungbean yellow mosaic India virus (MYMIV) in Assam and Orissa. Furthermore, we studied the population structure and genetic diversity of MYMV and MYMIV isolates of Vigna species reported to date from India. Interestingly, based on phylogenetics, we observed independent evolution of DNA-A and coevolution of DNA-B of MYMV and MYMIV. This finding is supported by the high mutation rate and recombination events in DNA-B, particularly in BV1 and BC1 genes over DNA-A, with high transition/transversion bias (R) for DNA-A over DNA-B. To investigate the effect of Begomovirus infection in plants, we constructed infectious clones (i.e. MYMV and MYMIV) and inoculated them to eight mungbean genotypes, cowpea (Vigna unguiculata L.) and tobacco (Nicotiana benthamiana) through agroinfiltration. The infected plants developed varying degrees of typical YMD symptoms. Based on the disease severity score and viral titre, mungbean genotypes were categorized as highly susceptible to MYMV (ML267) and MYMIV (K851) and immune to MYMV (PDM139, SML668) and MYMIV (Pusa Vishal). Conclusively, our findings may help prevent an epidemic of YMD in Vigna species and develop mungbean genotypes resistant to YMD via breeding programs.

Genetics for seed traits and Mungbean yellow mosaic India virus reaction in urdbean (Vigna mungo L. Hepper)

AbstractUrdbean or blackgram is one of the important multi‐season pulse crops grown in India. Improved seed quality and resistance to Mungbean yellow mosaic India virus (MYMIV) are the important objectives of the urdbean breeding program. For this, knowledge of inheritance for seed quality traits and MYMIV resistance is essentially required. Therefore, an attempt has been made to understand the inheritance of seed traits like seed luster, seed coat color, mosaic on seed surface, and MYMIV reaction using intra‐ and inter‐specific bi‐parental populations. The inheritance results revealed that in DPU88‐31 × LBG‐685 population, the shining seed registered dominance over the dull trait, while the green seed coat color exhibited dominance over the brown seed coat color. However, the inter‐specific F2 population derived from IPU11‐02 × Pant M 6 deviated significantly from Mendelian ratios and supported severe segregation distortion for seed traits, while the mosaic on seed coat or mottling character studied in interspecific population demonstrated a dominant digenic inheritance pattern. In five inter‐ and intra‐specific F2 populations, MYMIV resistance demonstrated monogenic dominant inheritance, which was also validated in F3 generations. Furthermore, linkage analysis exhibited an association between seed luster and seed coat color, while no association was noticed between seed traits and MYMIV resistance. The normality tests revealed that seed width and 100 seeds weight were controlled by a few major genes, while other quantitative traits were governed by many genes with small additive effects. The skewness suggested that complementary gene interactions were present among genes controlling 100 seed weight in the intra‐specific cross, while duplicate gene interactions were involved in the inter‐specific cross. The identified monogenic traits and linked morphological marker after further enrichment of the linkage group could be used as an important tool in the regular breeding program.

Development of improved genotypes for extra early maturity, higher yield and Mungbean Yellow Mosaic India Virus (MYMIV) resistance in soybean (Glycine max)

Context Breeding for early maturity and higher yield is the principal objective in genetic improvement of Indian soybean. Yellow Mosaic Disease caused by Mungbean Yellow Mosaic India Virus (MYMIV) causes 80% yield loss in soybean. Aims This study aimed to develop early maturing, MYMIV resistant and high yielding soybean genotypes for enhancing soybean production and expanding the land area under cropping. Methods MYMIV resistance was introgressed from G. soja in to a widely adaptable cultivar JS 335 through a series of four generations of backcrosses and by evaluating derived progeny against MYMIV at a disease hot spot. Key results An extra-early maturing (71 days) genetic stock called NRC 252 was developed, which can be a potential gene donor in breeding for early maturing soybean varieties. Introgression lines YMV 1, YMV 2, YMV 11 and YMV 16 with MYMIV resistance and higher yield performance over recurrent parent and other check varieties were identified and characterised. Biplot analysis, assessing the main effect of genotype and the interaction of genotype with environment, revealed an ideal genotype with respect to 100-seed weight and grain yield that was also promising under sugarcane-soybean intercropping system in spring season. Conclusions Alleles from wild type soybean could improve yield attributing traits and MYMIV resistance in cultivated soybean. Improved genotypes such as YMV 1, YMV 2, YMV 11 and YMV 16 were found superior to the recurrent parent JS 335 as well as other check varieties. Implications The genotypes developed in the present study will help in reducing the damage caused by MYMIV disease and expansion of the area of soybean cultivation through intercropping with sugarcane.

Identification of begomoviruses associated with the insect vector Bemisia tabaci and various host plants on Java Island, Indonesia.

Begomoviruses are economically important plant viruses and are transmitted by Bemisia tabaci which is a complex of various cryptic species. However, it is uncertain whether most begomoviruses that infect host plants are transmitted by B. tabaci at a similar rate. We compared the begomovirus profiles that were detected in a total of 37 whitefly populations and 52 host plants on Java Island, Indonesia. Seven begomovirus species were detected in B. tabaci at different rates: pepper yellow leaf curl Indonesia virus (PepYLCIV, 56.8%), tomato yellow leaf curl Kanchanaburi virus (TYLCKaV, 46.0%), tomato leaf curl New Delhi virus (ToLCNDV, 21.6%), squash leaf curl China virus (SLCCNV, 21.6%), ageratum yellow vein China virus (AYVCNV, 2.7%), mungbean yellow mosaic India virus (MYMIV, 2.7%), and okra enation leaf curl virus (OELCuV, 2.7%). The begomoviruses were detected at different rates in three cryptic species of B. tabaci. In addition, six begomovirus species were detected in the various host plants at different rates: PepYLCIV (67.3%), TYLCKaV (53.9%), ToLCNDV (13.5%), MYMIV (11.5%), AYVCNV (3.9%), and Tomato yellow leaf curl Thailand virus (TYLCTHV) (1.9%). By comparing the virus presence between whiteflies and plants, five begomoviruses (AYVCNV, MYMIV, PepYLCIV, ToLCNDV, and TYLCKaV) were detected in both samples, but their sequence similarity was highly variable depending on the begomovirus themselves; TYLCKaV was highest (99.4%-100%) than any other viruses. Our study suggests B. tabaci acquire begomoviruses at different rates from plants. This study provides important information on the potential variation in the begomovirus transmission mechanism.

A large-effect QTL introgressed from ricebean imparts resistance to Mungbean yellow mosaic India virus in blackgram (Vigna mungo (L.) Hepper).

Here, we report identification of a large effect QTL conferring Mungbean yellow mosaic India virus resistance introgressed from ricebean in blackgram variety Mash114. The tightly linked KASP markers would assist in marker-assisted-transfer of this region into Vigna species infected by MYMIV. Until recently, precise location of genes and marker-assisted selection was long thought in legumes such as blackgram due to lack of dense molecular maps. However, advances in next-generation sequencing based on high-throughput genotyping technologies such as QTL-seq have revolutionized trait mapping in marker-orphan crops. Using QTL-seq approach, we have identified a large-effect QTL for resistance to Mungbean yellow mosaic India virus (MYMIV) in blackgram variety Mash114. MYMIV is devastating disease responsible for huge yield losses in blackgram, greengram and other legumes. Mash114 showed consistent and high level of resistance to MYMIV since last nine years. Whole genome re-sequencing of MYMIV-resistant and susceptible bulks derived from RILs of cross KUG253 X Mash114 identified a large-effect QTL (qMYMIV6.1.1) spanning 3.4Mb on chromosome 6 explaining 70% of total phenotypic variation. This region was further identified as an inter-specific introgression from ricebean. Linkage mapping using KASP markers developed from potent candidate genes involved in virus resistance identified the 500kb genomic region equaling 1.9cM on genetic map linked with MYMIV. The three KASP markers closely associated with MYMIV originated from serine threonine kinase, UBE2D2 and BAK1/BRI1-ASSOCIATED RECEPTOR KINASE genes. These KASPs can be used for marker-assisted transfer of introgressed segment into suitable backgrounds of Vigna species.

NMR-Based Metabolomic Profiling of Mungbean Infected with Mungbean Yellow Mosaic India Virus.

Mungbean is an important legume mainly cultivated in Southeast Asia known for cheap source of food protein. Yellow mosaic disease (YMD) of mungbean is one of the most damaging diseases caused by mungbean yellow mosaic virus (MYMV) and mungbean yellow mosaic India virus (MYMIV) in India. The genetic basis of YMD resistance of mungbean is not well studied yet. Our present studies aimed to explore the genetic basis of YMD resistance through molecular, biochemical and metabolomics approach. Molecular analysis of YMV-infected mungbean plant materials revealed the presence of MYMIV. Chlorophyll contents were estimated as mosaic symptoms that cause chlorosis and necrosis in infected leaves. Chlorophyll a, b and total chlorophyll content were significantly reduced by 27-55% in infected samples compared non-infected control samples. 1H NMR-based metabolomic profiling of virus-infected mungbean were carried out, and we found that vital changes occurred during the development of MYMIV infection in mungbean. A total of fifty metabolites were identified in mungbean leaf samples. Principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) separated the severely infected sample from the non-infected samples. Orthogonal partial least discrimination analysis (OPLS-DA) revealed significant differences in MYMIV-infected and non-infected control samples. The featured metabolites in MYMIV infected and control samples were amino acids, carbohydrates, and organic acids. Relative abundance of sucrose, γ-amino butyric acid (GABA), proline, alanine, phenylalanine, tryptophan, pyruvate, ascorbate, and citrates were found as differential metabolites. Our results suggest that metabolic changes in infected mungbean samples is related to the viral acquisition. The present study may help in better understanding the metabolic alterations during biotic stress in mungbean.