Yellow Mosaic Disease Research Articles

Spectroscopic detection of wheat yellow mosaic virus infection based on invariant shape spectral processing and machine learning

Wheat yellow mosaic disease (WYMD) is a low-temperature soil-borne disease that causes serious yield and economic losses. Reflectance spectroscopy has great potential for detecting crop diseases, but it has not been applied for detection of WYMD. Herein, we collected 2 years of wheat physiological and reflectance spectroscopy data at green-up and jointing stages, and conducted disease detection studies. We evaluated standard normal variate (SNV), multiplicative scatter correction (MSC), and spectral separation of soil and vegetation (3SV) as preprocessing methods for invariant spectral shapes, and 96 spectral indices. The spectral index wavelength (SIW), threshold method, and variance inflation factor (TVIF) were used as feature selection methods combined with machine learning to construct a systematic disease detection scheme. The results showed that the visible region centred at 750 nm was the most sensitive wavelength. Additionally, 900–––1000 nm was the sensitive wavelength in the middle and latter stages, during disease aggravation and fertility development. The preprocessing method was best with 3SV, which was highly consistent with the characteristic regions of the original spectra, followed by SNV and MSC. spectral indices OR-BG1 I, SNV-RPMI, MSC-RPMI and 3SV-CTRI 1 could be applied to detect WYMD, and the best index was 3SV-CTRI 1, with OA and Kappa values of 75.88% and 0.516, respectively. The effectiveness of the SIW feature selection method and coupling with machine learning was superior to TVIF. The best results among different machine learning models were obtained with SVM, followed by RF and KNN. The optimal 3SV-SIW-SVM disease detection mode achieved OA and Kappa values of 94.71% and 0.893, respectively, for field data validation, and 68.06% and 0.381, respectively, for simulated satellite data validation. The findings will facilitate migration of ground-based research to satellite platforms, and provide new ideas for quantitative identification of crop diseases.

First Report of Tomato Leaf Curl Cebu Virus Associated with Stachytarpheta jamaicensis Golden Yellow Mosaic Disease in Taiwan.

Stachytarpheta jamaicensis (L.) Vahl, also known as snack weed, is an exotic plant in Taiwan. In April 2021, severe golden yellow mosaic leaves (Fig. S1) were observed on S. jamaicensis plants in Taichung City, Taiwan. Samples from eight symptomatic and two asymptomatic plants were collected from the public flowerbed. Total DNA was extracted from each of the collected samples by using a modified CTAB method (Echevarría-Machado et al. 2005). PCR with Begomovirus degenerate primers (PAL1v1978/PAR1c715; Rojas et al. 1993) was conducted. The expected 1.5-kb fragment was amplified only from the 8 symptomatic samples. Two randomly selected amplicons were cloned on pCRII-TOPO TA vector (Invitrogen Co., San Diego, CA, USA) and sequenced with the ABI3730 automatic sequencer (Applied Biosystems, Hammonton, NJ, USA) at National Chung Hsing University (NCHU). After NCBI BLASTn analysis, the sequences were shown to be most closely related to tomato leaf curl Cebu virus (ToLCCeV) isolates (EU487042, EU487025, KU946997), with 92.4-92.5% nucleotide sequence identity by using the CLUSTAL W method of MegAlign program (DNASTAR, Inc., Madison, WI, USA). A ToLCCeV specific primer pair (FJJ2021-165 /166 5'-ACTTACAGGCCCATGTATCG-3' / 5'-GAATGGGTATCCGAGCACG-3') was designed to amplify and sequence the remaining half of viral DNA. The expected 1.6-kb amplicon was amplified only from the symptomatic samples. The full-length of DNA-A consisted of 2.7-kb nucleotides (ToLCCeV isolate stachy, ON525110 and ON525111) and contained six open reading frames (two in viral sense, V1 to V2 and four in the viral complementary sense, C1 to C4) and the conserved nonanucleotide motif (TAATATTAC). The full-length DNA-A of ToLCCeV stachy isolates shared 99.9% nucleotide identity to each other and 91.2-92.4% and 91.3-92.5% nucleotide identities to other ToLCCeV isolates (EU487042, EU487025, KU946997) available in NCBI GenBank. Besides, ToLCCeV is a monopartite begomovirus that harbors no DNA-B. Thus, there were no bands amplified from the degenerate primer pair for DNA-B (DNABLC2 / DNABLV2; Green et al. 2001). Furthermore, the infectious clone was constructed by using phi29 DNA polymerase (New England Biolabs, Ipswich, MA, USA) for rolling circle amplification (RCA). The RCA product was partially digested with ApaI (NEB) and ligated into the binary vector pCambia0380 (AF234290). The resulting recombinant vector was transformed into Agrobacterium tumefaciens C58. A. tumefaciens C58, containing the infectious ToLCCeV-Stachy DNA-A vector, was grown overnight in LB broth containing kanamycine (50 μg/ml) at 28°C. S. jamaicensis and Nicotiana benthamiana (Nb, four to six leaf stage) plants were agroinoculated to confirm the infectivity of the ToLCCeV clone. The leaf curling and blister symptoms were observed on the Nb systemic leaves 17-day post inoculation (dpi) and the golden yellow mosaic symptom noticed on S. jamaicensis systemic leaves 30-dpi. The presence of the viral DNA in the inoculated plants was confirmed by PCR using the specific primer pair of ToLCCeV. To the best of our knowledge, this is the first report of the monopartite begomovirus, ToLCCeV, associated with golden yellow mosaic disease in S. jamaicensis in Taiwan. The existence of ToLCCeV might severely impact the tomato and pepper industry because they are the natural hosts of ToLCCeV (Tsai et al. 2011) and ToLCCeV may be transmitted by the whitefly, Bemisia tabaci, in Taiwan (Ko et al. 2005).

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.

First report of a begomovirus and associated betasatellite causing yellow vein mosaic disease of Celosia cristata

First report of a begomovirus and associated betasatellite causing yellow vein mosaic disease of <i>Celosia cristata</i>

Virus–vector relationship of squash leaf curl China virus and its transmission through whitefly vector, Bemisia tabaci (Gennadius) causing yellow vein mosaic disease of pumpkin

Virus–vector relationship of squash leaf curl China virus and its transmission through whitefly vector, Bemisia tabaci (Gennadius) causing yellow vein mosaic disease of pumpkin

Impact of Large Scale Demonstration on Productivity and Profitability of Blackgram Under Rainfed Conditions of Chamarajanagara District, Karnataka (Zone-6)

Background: Blackgram is a major pulse crop grown next to horsegram and greengram in Chamarajanagar district. Unavailability of high yielding and yellow mosaic resistant varieties, poor agronomic and pest management practices has led to drastic fall down in productivity and profitability of blackgram in Chamarajanagara district. Methods: Large scale demonstration was conducted in an area of 60 ha covering 150 farmers of K. Mukahalli, Kotamballi, Devalapura, Doddatuppuru and Y.K. mole villages. Further the integrated crop management practices in blackgram variety LBG-791 was demonstrated during Pre-kharif of 2020-21, 2021-22 and 2022-23 by ICAR-Krishi Vigyan Kendra, Chamarajanagara, Karnataka. Result: The Yellow mosaic disease incidence was significantly less in LBG-791 (1.40%) when compared to T-9 (Farmers’ variety) (66.8%). Adoption of LBG-791 along with improved crop management practices resulted in 121.5% higher mean grain yield as compared to farmers practice. Higher Benefit: Cost ratio of 1.94 was recorded with integrated crop management practices as compared to farmers’ practices (1.03). The study exhibited mean extension and technology gap of 379 kg/ha and 119 kg/ha respectively. Further the mean technology index was 14.73 per cent. These results indicate that there is a great opportunity for farmers of Karnataka (Zone-6) for increasing productivity and profitability of the blackgram crop by adoption of Integrated Crop Management Practices (ICMP).

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.

Impact assessment of natural variations in different weather factors on the incidence of whitefly, Bemisia tabaci Genn. and yellow vein mosaic disease in Abelmoschus esculentus (L.) Moench

Bemisia tabaci Gennadius, also renowned as the silver leaf whitefly, is among the most damaging polyphagous insect pests in many commercially important crops and commodities. A set of field experiments were conducted for three consecutive years i.e., 2018–2020, to investigate the role of variations in rainfall, temperature, and relative humidity on the abundance of B. tabaci in okra (Abelmoschus esculentus L. Moench). In the first experiment, the variety Arka Anamika was cultivated twice a year to analyse the incidence of B. tabaci concerning the prevailing weather factors and the overall pooled incidence recorded during the dry and wet season was 1.34 ± 0.51 to 20.03 ± 1.42 and 2.26 ± 1.08 to 18.3 ± 1.96, respectively. Similarly, it was observed that the highest number of B. tabaci catch (19.51 ± 1.64 whiteflies/3 leaves) was recorded in morning hours between 08:31 to 09:30 a.m. The Yellow Vein Mosaic Disease (YVMD) is a devastating disease of okra caused by begomovirus, for which B. tabaci acts as a vector. In another experiment, screening was conducted to check the relative susceptibility of three different varieties viz., ArkaAnamika, PusaSawani, and ParbhaniKranti against B. tabaci (incidence) and YVMD ((Percent Disease Incidence (PDI), Disease Severity Index (DSI), and Area Under the Disease Progress Curve (AUDPC)). The recorded data was normalized by standard transformation and subjected to ANOVA for population dynamics and PDI. Pearson's rank correlation matrix and Principal Component Analysis (PCA) have been used to relate the influences of various weather conditions on distribution and abundance. SPSS and R software were used to create the regression model for predicting the population of B. tabaci. Late sown PusaSawani evolved as a highly susceptible variety in terms of B. tabaci (24.83 ± 6.79 adults/3leaves; mean ± SE; N = 10) as well as YVMD i.e., PDI (38.00 ± 4.95 infected plants/50plants), DSI (71.6–96.4% at 30 DAS) and AUDPC (mean β-value = 0.76; R2 = 0.96) while early sown Parbhani Kranti least susceptible to both. However, the variety ArkaAnamika was observed as moderately susceptible to B. tabaci and its resultant disease. Moreover, environmental factors were predominantly responsible for regulating the population of insect pests in the field and hence its productivity like rainfall and relative humidity were negative while the temperature was positively correlated with B. tabaci (incidence) and YVMD (AUDPC). The findings are helpful for the farmers to choose need-based IPM strategies than timing-based, which would fit perfectly with the present agro-ecosystems in all ways.

Molecular insights into the responses of barley to yellow mosaic disease through transcriptome analysis

BackgroundBarley (Hordeum vulgare L.) represents the fourth most essential cereal crop in the world, vulnerable to barley yellow mosaic virus (BaYMV) and/or barley mild mosaic virus (BaMMV), leading to the significant yield reduction. To gain a better understanding of the mechanisms regarding barley crop tolerance to virus infection, we employed a transcriptome sequencing approach and investigated global gene expression among three barley varieties under both infected and control conditions. ResultsHigh-throughput sequencing outputs revealed massive genetic responses, reflected by the barley transcriptome after BaYMV and/or BaMMV infection. Significant enrichments in peptidase complex and protein processing in endoplasmic reticulum were clustered through Gene ontology and KEGG analysis. Many genes were identified as transcription factors, antioxidants, disease resistance genes and plant hormones and differentially expressed between infected and uninfected barley varieties. Importantly, general response genes, variety-specific and infection-specific genes were also discovered. Our results provide useful information for future barley breeding to resist BaYMV and BaMMV.ConclusionsOur study elucidates transcriptomic adaptations in barley response to BaYMV/BaMMV infection through high-throughput sequencing technique. The analysis outcome from GO and KEGG pathways suggests that BaYMV disease induced regulations in multiple molecular-biology processes and signalling pathways. Moreover, critical DEGs involved in defence and stress tolerance mechanisms were displayed. Further functional investigations focusing on these DEGs contributes to understanding the molecular mechanisms of plant response to BaYMV disease infection, thereby offering precious genetic resources for breeding barley varieties resistant to BaYMV disease.

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.

Improved Spectral Detection of Nitrogen Deficiency and Yellow Mosaic Disease Stresses in Wheat Using a Soil Effect Removal Algorithm and Machine Learning

Wheat yellow mosaic disease is a low-temperature and soil-borne disease. Crop infection by the yellow mosaic virus can lead to severe yield and economic losses. It is easily confused with nitrogen deficiency based on the plant’s morphological characteristics. Timely disease detection and crop management in the field require the precise identification of crop stress types. However, the detection of crop stress is often underappreciated. Wheat nitrogen deficiency and yellow mosaic disease were investigated in the field and wheat physiological and biochemical experiments were conducted to collect agronomic indicators, four years of reflectance spectral data at green-up and jointing were collected, and then studies for the detection of nitrogen deficiency and yellow mosaic disease stresses were carried out. The continuous removal (CR), first-order derivative (FD), standard normal variate (SNV), and spectral separation of soil and vegetation (3SV) preprocessing methods and 96 spectral indices were evaluated. The threshold method and variance inflation factor (TVIF) were used as feature selection methods combined with machine learning to develop a crop stress detection method. The results show that the most sensitive wavelengths are found in the 725–1000 nm region, while the sensitivity of the spectrum in the 400–725 nm region is lower. The PRI670,570, B, and RARSa spectral indices can detect nitrogen deficiency and yellow leaf disease stress, and the OA and Kappa values are 93.87% and 0.873, respectively, for PRI670,570, which is the best index. A 3SV-TVIF-SVM stress detection method was then proposed, using OA and Kappa values of 96.97% and 0.931, respectively, for field data validation. The results of the study can provide technical support and a theoretical basis for the accurate control of yellow mosaic disease and nitrogen fertilizer management in the field.

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.

Cross-species amplification and genetic variation among blackgram genotypes using SSR markers developed from mungbean DNA sequence scaffolds harbouring putative resistance genes

The cross species amplification of 97 mungbean derived resistance gene-SSR markers were investigated for diversity analysis in a set of 44 blackgram genotypes. A total of 68(70%) SSR markers showed amplification in blackgram. Our of 68 markers, thirty randomly selected markers were used to study the genetic variation among 44 blackgram genotypes varying for yellow mosaic disease (YMD) and powdery mildew disease (PMD) reaction. Thirty SSR primers collectively amplified 90 alleles in blackgram with an average of three alleles/locus. The polymorphic information content (PIC) of the SSR markers ranged from 0 to 0.86 with an average of 0.43. Cluster analysis based on UPGMA neighbour-joining method grouped the 44 genotypes into seven clusters. The genotypes NDU-1 and PU-19 were observed to be highly dissimilar with similarity coefficient of 0.27 in comparison to other genotypes. YMD and PMD resistant and susceptible genotypes could be differentiated by three (MRGSSR 12, MRGSSR 56, MRGSSR 77) and four SSR markers (MRGSSR12, MRGSSR 32, MRGSSR56 and MRGSSR65), respectively. Two of these markers viz., &nbsp;MRGSSR12 and MRGSSR56 were mutually effective in differentiating YMD and PMD resistant genotypes. These were located in mungbean scaffolds JJMO01002369 and &nbsp;JJMO01001477 and exhibited homology with TMV resistance protein N and DNA damage-repair/toleration protein DRT100, respectively. Keywords: Blackgram, Cross species amplification, Resistance genes, Genomic-SSR, Polymerase chain reaction, Diversity analysis.

Evaluation of F1 hybrids for horticultural and quality traits and pumpkin yellow vein mosaic disease resistance in pumpkin

Pumpkins being cheap and having higher medicinal value can act as a saviour to low-income families. Butbeing a minor crop, little attention has been paid to its improvement. The hybridization in pumpkins is economicallyfeasible due to the monoecious nature and higher number of seeds per fruit. Moreover, the development of superiorhybrids can enhance production and consumption through ease in cultivation, meeting consumers’ preferencesand suitability to different seasons. Hitherto, 34 F1 hybrids were evaluated during spring and rainy seasons forstandard heterosis. H9 (P-225 × GFR-6783) and H28 (VR-1365 × VR-13364) hybrids exhibited maximum standardheterosis for yield per plant and can be exploited for commercial cultivation. Resistance to PYVMD is a pre-requisitefor the successful cultivation of pumpkin in the rainy season. 11 hybrids (H24, H25, H26, H27, H28, H29, H30, H31,H32, H33 and H34) tolerant to PYVMD offered the advantage of cultivating pumpkin in both seasons.

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.

Seed Transmission of Begomoviruses: A Potential Threat for Bitter Gourd Cultivation.

Bitter gourd (Momordica charantia L.), one of the valued vegetable crops in India, is severely affected by yellow mosaic disease caused by two begomoviruses, tomato leaf curl New Delhi virus (ToLCNDV) and bitter gourd yellow mosaic virus (BgYMV). The symptoms are yellowing, distortion of leaf, puckering, and malformed fruits. Increased incidence of the disease and appearance of symptoms even in young emerging seedling stage were suggestive of seed transmission of the viruses, which was examined in detail. To study the seed transmission, two sources-seeds of elite hybrids H1, H2, H3, H4, and Co1 procured from a seed market; and seeds from infected plants in the farmer's field were tested. Detection of the virus by DAS-ELISA using polyclonal antibody indicated embryo infection up to 63%, 26%, 20%, and 10% in hybrids H1, H2, H3, and H4, respectively, for market-procured seeds. In PCR analysis with primers specific for ToLCNDV and BgYMV, infection by ToLCNDV was as high as 76% and mixed infection was 24%. In contrast, in seeds derived from field-infected plants, the percentage detection was less. Grow-out tests with market-procured seeds revealed no transmission for BgYMV compared with 5% transmission for ToLCNDV. Whether seed-borne inocula could serve as an inoculum for new infection in a field and further progress of the disease was investigated in a microplot study. The study clearly revealed variation in seed transmission between different sources, lots, cultivars, and viruses. The virus present in symptomatic and asymptomatic plants was easily transmitted by whitefly. In another microplot experiment, the potential of seed-borne virus as inoculum was proved. There was 43.3% initial seed transmission in the microplot, increasing to 70% after release of 60 whiteflies.

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.

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.

CRISPR/Cas9-guided knockout of eIF4E improves Wheat yellow mosaic virus resistance without yield penalty.

CRISPR/Cas9-guided knockout of eIF4E improves Wheat yellow mosaic virus resistance without yield penalty.