Mungbean Yellow Mosaic Virus Research Articles

Development of bruchid pest and mungbean yellow mosaic virus disease resistance lines in blackgram [Vigna mungo (L.) Hepper] through marker- assisted selection

Bruchid beetles (Callosobruchus maculatus) and mungbean yellow mosaic virus (MYMV) disease are the two major causes of yield constraints in blackgram. Marker-assisted selection was performed among a population developed from the cross combinations of MDU 1 (susceptible female parent) and the TU 68 (resistant male parent) to select for bruchid and MYMV disease resistance. The selected introgression lines (ILs) were significantly superior for bruchid and MYMV disease resistance traits. The introgression lines namely IL-9-1, IL-12-1, IL-12-2, IL-12-7, IL-12-9 and IL-12-10 recorded higher seed yield during the disease prevalent environment than the female parent MDU 1. But the yield performances were lower than the female parent MDU 1 in the disease-free environment. The reduced performance for yield might be due to the linkage drag among the introgression lines. Hence, the linkage drag can be eliminated by the backcross breeding method. However, the successful selection for dual biotic resistance was achieved among the introgression lines. Further, better recombinants must be isolated to obtain good yielding variety and bruchid and MYMV disease resistance.

The ricebean genome provides insight into Vigna genome evolution and facilitates genetic enhancement.

The ricebean genome provides insight into Vigna genome evolution and facilitates genetic enhancement.

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.

Gene Effects of Quantitative Traits through Six Parameter Model of Generation Mean Analysis in Black Gram [Vigna mungo (L.) Hepper

Background: Yellow mosaic disease (YMD) caused by Mungbean Yellow Mosaic Virus (MYMV) is one of the most destructive biotic constraints for production in urdbean. Development and introduction of resistant cultivars with high seed yield is considered as the most economical and eco-friendly option to manage YMD, for which understanding the gene action controlling the inheritance of different traits along with YMD resistance is an important requirement. Methods: Material comprised of four diverse genotypes (TU 94-2, PU 31, IPU 94-1 and LBG 623), six F1s, six BC1s and six BC2s and six F2s. These six generations of all the six crosses were evaluated for various yield related traits in rabi, 2020-21 and phenotyped for YMD in summer, 2021 at Lam, Guntur, Andhra Pradesh which is hotspot for YMD. Result: Inadequacy of additive-dominant model for all most all traits including YMD except for test weight was observed. It was found that, [l] type of non-allelic interaction was observed to be predominant for majority of the traits. Further, the existence of duplicate type of epistasis in the inheritance was evident at least in few crosses for all the traits (except days to maturity). The duplicate epistasis will reduce the variation in F2 and subsequent generations, thereby hinder the pace of the progress through selection.

Prevalence of mungbean yellow mosaic virus on greengram in northern parts of Karnataka

Globally, mungbean yellow mosaic disease acting as a major constraint of greengram production. Its incidence isalso gradually increasing in northern parts Karnataka. Mungbean yellow mosaic disease has peculiar symptoms likeinitially yellow-coloured spots scattered on young leaves followed by yellow mosaic pattern and puckering and slowdrying of yellow leaves and wither. Infected plants bear few flowers and pods with some immature and deformed seeds.Pods of the infected plants were reduced in size and turned yellow in colour. Roving survey was conducted for two seasons,viz., kharif 2021 and summer 2021-22 to know per cent disease incidence in Bagalkot, Belagavi, Dharwad, and Gadagdistricts of northern parts of Karnataka. Among the four districts, average maximum incidence of 16.85 per cent wasrecorded in Gadag followed by Dharwad (15.01%), whereas the lowest incidence of 11.58 per cent was noticed in Bagalkotdistrict during kharif. Maximum incidence of 30.10 per cent was recorded in Dharwad followed by Belagavi (25.02%),whereas the lowest incidence of 20.59 per cent was noticed in Bagalkot district during summer.

Epidemiology and Management of MYMV Disease in Mung Bean (Vigna radiata (L.))

Mung bean is a short-duration ancient legume crop that can be grown as a sole or intercrop for grain and green manure in all three crop seasons, including winter, summer and rainy in various regions of the country. MYMV (Mungbean Yellow Mosaic Virus) disease is one of the most destructive diseases transmitted by whitefly (Bemisia tabaci Genn) persistently. Weather parameters have no direct effect on MYMV, but affect the whitefly population. Field experiments were conducted for three consecutive years from 2019-2021 as to know the effect of weather parameters on the whitefly population. Development of whitefly population and MYMV disease severity were recorded in mungbean crops at 7 days interval starting from 20 days after sowing (DAS). The present study showed that whitefly population builds up starting in July and reached to maximum at end of August to early September. There are various factors influencing the build-up of whitefly population viz., maximum temperature 36±2°C, minimum temperature 25±2°C, morning relative humidity more than 90 percent, more sunshine hours and no rainfall prevailing during that period. Whitefly population had positive significant correlation with maximum temperature and bright sunshine hours while evening relative humidity and rainfall were recorded as negatively significant. Three-year data is very helpful in guiding the farmers for timely and preventive sprays based on existing infections and the population of whitefly in a season.

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.

Influence of meteorological parameters on incidence of mungbean yellow mosaic virus disease in green gram in Assam

Green gram (Vigna radiata) is one of the most important pulse crops grown in India and abroad bean yellow mosaic virus disease caused by Mung bean yellow mosaic virus has become a major threat in greengram cultivation in Assam. An experiment was conducted in the Experimental field, Department of Plant Pathology, Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali during 2021-22, where green gram was sown in five dates starting from 5th September 2021to 3rd October 2021 at 7 days interval to study the effect of meteorological parameters in the incidence of green gram yellow mosaic virus disease, effect on growth and yield parameters so as to find out the best sowing time of the crop as a strategy for managing the disease. During the study, symptoms like, appearance of chlorotic specks along the veins, puckering of leaves, typical mosaic pattern, complete yellowing and drying of the leaves were recorded. Highest whitefly population (12.42 no/plant) was recorded in the crop sown on 19.09.2021 and the lowest (6.24no/plant) was recorded in the 05.9.2021 sown crop. Lowest (40.32%) disease incidence with highest seed yield (4.50 q/ha) was recorded in the crop sown on 05.09.2021, whereas highest (88.25%) disease incidence with lowest yield (2.50 q/ha) was recorded in the crop sown in second fortnight of September (19.09.21). Maximum temperature ranging from 29-33 oC, minimum temperature 13-23 oC with 8-9 bright sunshine hours were found to be conducive for incidence and rapid spread of the disease.

Morphological Screening of Black Gram Genotypes with Reference to Mung Bean Yellow Mosaic Virus

One of the most devastating diseases affecting blackgram productivity in India is mung bean yellow mosaic. It is transmitted by whitefly (Bemisia tabaci). The current investigation was carried out to identify the blackgram genotypes resistant against the Mung bean yellow Mosaic virus (MYMV) through field screening at natural condition. The genotypes were screened using the infector row method. Twelve blackgram genotypes namely VBN-2, VBN-3, VBN-5, VBN-6, VBN-7 VBN-8, VBN-9 VBN-10, VBN-11, ADT-5, ADT-6 and CO-5 were used for screening during summer 2022. The genotypes viz., VBN-6, VBN-10 and VBN-11 were found to be resistant and moderately resistant viz., VBN-4, VBN-5, VBN-7, and VBN-8. It implies that utilization of these genotypes as YMV resistance donors for results in the production of high yielding MYMV resistant varieties through backcrossing or marker assisted backcrossing by introgression of the genes to agronomically potential genotypes that were susceptible to MYMV.

Validation of IPM Modules for the Management of Whitefly, Bemisia tabaci and Mungbean Yellow Mosaic Virus Disease in Greengram

Greengram is known to be infected by several viral diseases. Among them, Mungbean Yellow Mosaic Virus (MYMV) is the most destructive in India, and it is popularly known as the yellow plague. MYMV transmitted exclusively through plant-to-plant by whitefly, Bemisia tabaci (Gennadius). For the management of MYMV, vector control is the only possible option. Hence, the attempt was made to evaluate IPM modules against whiteflies by reducing their population or disrupt MYMV transmission. The field experiment was conducted at Agricultural and Horticultural Research Station, Bhavikere, during the Kharif seasons of 2018 and 2019. The results of two seasons indicated that, the lowest whitefly population (1.70 per trifoliate leaf) and significantly lowest MYMV incidence was recorded in module-3 (Maize as a border crop + one spray of NSKE 5 % at 20 days after sowing + one spray of fish oil rosin soap @ 5ml/liter at 40 DAS). The highest grain yield (9.64 q/ha) and cost: benefit ratio (1: 3.23) was recorded in this module, followed by module-1 (Maize as a border crop + Seed treatment with imidacloprid 600 FS @ 5 ml per kg of seeds). For the management of MYMV and its vector whitefly, B. tabaci module-3 was effective compared to the standard check (Dimethoate 30 EC at the rate of 1.75 ml per liter). The importance of IPM in whitefly management to reduce virus incidence is discussed.

Field Screening and Molecular Characterization of Urdbean Genotypes for Yellow Mosaic Disease

Background: Urdbean [Vigna mungo (L.) Hepper] is an important pulse crop in India as well as in South East Asia. It is an excellent source of easily digestible, good quality protein. Mungbean Yellow Mosaic Virus causing Yellow mosaic disease (YMD) is one of the most devastating diseases affecting urdbean production and productivity to a large extent. Identification of resistant genotypes is one of the most important aspects in the management of MYMV diseases. The current study aimed to identify the MYMV resistant urdbean genotypes in order to manage and control the MYMV disease. Methods: In present investigation, a total 100 urdbean genotypes were screened against MYMV under natural field conditions in the augmented design by planting 2 rows of two test entries each alternated with one row of susceptible check. Further, selected genotypes which showed disease free, highly resistant, resistant, moderately resistance and susceptible reaction in field screening were used to tag RAPD markers associated with MYMV resistance in urdbean. Result: Out of 100 genotypes tested, only one genotype, NDU 12-1 was found to be disease free, twenty seven genotypes found to be highly resistance and four genotypes showed resistance consistently for four consecutive seasons (two summer and two Kharif) during 2017-2018. However, four genotypes were found to be superior for seed yield among all the genotypes tested as well as resistant to MYMV. The RAPD analysis clearly grouped all the MYMV resistant genotypes studied in cluster I whereas the susceptible genotypes were clustered together in the cluster II. The present work has successfully identified the MYMV resistant urdbean genotypes which can be used in MYMV resistance breeding programme.

Biological and molecular characterization of Mungbean yellow mosaic virus (MYMV) and its vector, Bemisia tabaci cryptic species in greengram

Biological and molecular characterization of Mungbean yellow mosaic virus (MYMV) and its vector, Bemisia tabaci cryptic species in greengram

DISEASES OF MOTH BEAN [VIGNA ACONITIFOLIA (JACQ.) MARECHAL

Pulses are obtained from leguminous plants that have many bioactive components and good nutritional value, being rich in protein, vitamins, and abundant macro- and micronutrients and thus contribute to global food security. Moth bean is compatible with the climatic conditions of Rajasthan because it is a drought-resistant crop though it is affected by many pathogenic microorganisms as fungi, bacteria, and viruses. Infection of these microorganisms causes damage to plants which results in loss of productivity. In the current context, a review on fungal, bacterial, and viral diseases of moth bean has been dealt with. The major diseases of moth bean reported are leaf blight, leaf spots, seedling stem and root rot, pod rot, web blight, common bacterial blight, and mung bean yellow mosaic virus (MYMV) causing yield loss.

Coat Protein Characterization of Mungbean yellow mosaic virus Infecting Blackgram (Vigna mungo L. Hepper) in Tamil Nadu

The Yellow Mosaic Disease is the main constraint for decreased yield in blackgram production. Coat protein gene of Mungbean yellow mosaic virus (MYMV) has been characterized and phylogenetic tree was constructed. The genomic DNA from diseased plants was collected and it was tested for it’s quality and quantity using a Nanodrop. The isolated DNA was subjected to polymerase chain reaction using begomovirus universal primers for preliminary confirmation of the virus. The samples amplified for universal primers were subjected for gene specific amplification using DNA A primers. The DNA A primers resulted in the amplification of the expected size of 1000 bp amplicon. The DNA fragments were sequenced and the sequence results of DNA A were compared with other sequences available in NCBI and it showed higher similarity with Mungbean yellow mosaic virus banglore coat protein gene (accession no: MK409376). The sequence was submitted in NCBI database and accession numbers were obtained. The phylogenetic tree was constructed using mega 11 software by comparing the selected strains with our isolate.

Manipulating resistance to mungbean yellow mosaic virus in greengram (Vigna radiata L): Through CRISPR/Cas9 mediated editing of the viral genome

Clustered regularly interspaced short palindromic repeats (CRISPR) associated protein (CRISPR/Cas9) is an adaptive immune system of bacteria to counter the impending viral pathogen attack. With persistent improvements, CRISPR has become a versatile tool for developing molecular immunity against viruses in plants. In the current report, we utilized the Cas9 endonuclease and dual 20 bp-gRNAs targeting two different locations in single-stranded DNA-A of AC1 (rep protein) and AV1 (coat protein) of mungbean yellow mosaic virus for achieving resistance in greengram. The cotyledonary nodal explants were infected with Agrobacterium strain EHA105 harboring pMDC100-Cas9 with AC1 and AV1 gRNA cassettes and generated transgenic plants. The integration of Cas9 and gRNA cassettes in the transformed plants of greengram were confirmed by PCR and dot blot assays. Agroinfiltrated T2 transgenic lines exhibited minimal mosaic symptoms. A drastic reduction in the accumulation of AC1 and AV1 was observed in T2 transformed lines. The T7EI assay indicated that AC1 fragments were edited at a frequency of 46%, 32%, 20%, and AV1 at 38.15%, 40%, and 21.36% in MYMV infected greengram lines T2-6-2-3, T2-6-4-4, and T2-6-4-7, respectively. The manipulation of resistance to MYMV through the editing of the pathogen genome using the CRISPR/Cas9 tool can be a powerful approach to combat viruses and develop resistance in greengram.

Molecular epidemiology on seasonal variation of yellow mosaic disease incidence in blackgram (Vigna mungo L. Hepper) with its vector Bemisia tabaci.

The yellow mosaic disease (YMD) of blackgram caused by Mungbean yellow mosaic virus has emerged as a serious threat to grain legume production, especially in Southeastern Asia. Seasonal incidence of YMD with its vector population was assessed in three different agroclimatic zones of Tamil Nadu in India for three consecutive cropping seasons namely, Rabi 2018 (October-December), Summer 2019 (March-May), and Kharif 2019 (June-August) at three different time intervals viz., 20, 40, and 60days after sowing (DAS). For all three seasons, disease incidence and whitefly count were recorded for a resistant and susceptible variety of blackgram in fields without any vector control intervention. The highest disease incidence (87%) was observed in the Panpozhi location during the summer season followed by Vamban and Coimbatore locations. The whitefly count was made through both visual count and yellow sticky traps. The whitefly population was highest at 20 DAS and decreased with the increasing age of crop for all the three locations assessed. Molecular epidemiology was analyzed by determining latent infection of mungbean yellow mosaic virus (MYMV) using molecular diagnosis. Latent infection was found to be well pronounced in the Coimbatore location during the Kharif season, where the crop was asymptomatic in both the resistant and susceptible varieties for all the three time periods assessed. The latent infection of MYMV observed in Coimbatore and Vamban ranged from 16.6 to 83.3% in both resistant and susceptible varieties for all three seasons. In Panpozhi, the latent infection of MYMV ranged from 16.6 to 66.6% for the susceptible variety (CO-5) for all three seasons observed. However, in the Panpozhi location, the resistant variety (VBN-8) failed to record any latent infection.

Retraction: The impact of insecticides and plant extracts on the suppression of insect vector (Bemisia tabaci) of Mungbean yellow mosaic virus (MYMV).

Retraction: The impact of insecticides and plant extracts on the suppression of insect vector (Bemisia tabaci) of Mungbean yellow mosaic virus (MYMV).

Major diseases of field and horticultural crops in Northern Bihar region of India

A survey was conducted to determine the status of major diseases of field and horticultural crops grown in Saharsa, Supaul, Madhepura and Khagaria districts of northern Bihar, India. Three blocks in each district and three villages in each block were surveyed through a random field survey method. Per cent disease incidence was recorded on randomly selected plants in a particular field of selected location. The incidence of diseases was observed on the basis of typical field symptoms and later the association was confirmed through microscopic examinations in the laboratory. In view of maximum diseases incidence; foliar blight of wheat, sheath blight of rice, turcicum leaf blight of maize, mungbean yellow mosaic virus, Alternaria blight of mustard were recorded with >50% incidence in these districts. However, dry root rot and wilt of chickpea and lentil, wilt of pigeonpea, powdery mildew of pea, Alternaria leaf spot of linseed, Fusarium wilt and red rot of sugarcane and root rot of jute were noticed with 10 to 50% incidence. In fruit crops; sigatoka disease of banana was noticed with >50% incidence, while, anthracnose/ die back and floral malformation of mango, wilt of banana, foot rot of papaya and anthracnose of guava and citrus canker were observed with 10-50% incidence. Diseases viz., late blight, bacterial wilt, black leaf spot/ rot, leaf curl, yellow vein mosaic virus, die back and late blight were recorded with >50% incidence in tomato, brinjal, cauliflower, cucurbits, okra, chilli and potato, respectively. The purple blotch of onion, black leaf rot of cabbage and collar rot of elephant foot yam were noticed with 10-50% incidences.

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.

EVALUATION OF MASH (Vigna mungo (L.) HEPPER) LINES/ GENOTYPES FOR RESISTANCE/ TOLERANCE TO URDBEAN LEAF CRINKLE VIRUS (ULCV) AND MUNGBEAN YELLOW MOSAIC VIRUS (MYMV) USING CLUSTER ANALYSIS

A field experiment comprising of 40 mash bean genotypes were conducted to screen the germplasm for Mung bean yellow mosaic virus and urdbean leaf crinkle virus. The genotypes were also evaluated for chlorophyll contents. The experiment was laid out using randomized complete block design with three replications. Analysis of variance was done to find out differences among the genotypes for MYMV and ULCV and chlorophyll contents. Significant variation was found for both diseases and chlorophyll contents. Cluster analysis revealed that cluster 3 genotypes with lower ULCV and lowest MYMV disease. The genotype 20M011 showed no symptoms of the MYMV disease followed by 21M001, 21M009, 62027, M-97, 20M004, 19M008 which exhibited disease incidence of 1%. Regarding studies of ULCV disease in same genotypes it was revealed that minimum infestation was found in genotype 20M003 4.0% followed by 19 M010, 16M004, 17 M011, 20M003, 20M012, 21M002, 21M004, 21M005, 21M006 with a value of 8.0%. The genotypes with higher tolerance may be exploited in breeding programmes aimed at the development of varieties having higher disease tolerance.