Yellow Mosaic Disease Research Articles

Begomovirus disease of pumpkin crop in India and its management strategies possibility: a review

Pumpkin is an important commercial crop grown worldwide in tropical and subtropical regions. The whitefly-transmitted Pumpkin yellow vein mosaic disease seriously threatens pumpkin cultivation worldwide. The advent of transgenic technology in the 1980s revolutionized the possibilities for introducing virus resistance into agriculturally important plant species. It offered a powerful tool to enhance crop protection and provided a pathway to potentially unlimited sources of resistance against viral diseases. The ongoing research and development in this field continue to explore and refine conventional and non-conventional approaches for effective virus management in agriculture crops. This review focuses on developing transgenic resistance against begomoviruses and discusses possible management strategies to address these challenges.

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.

Identification of genes governing YMD resistance in soybean cultivar SL 958.

Yellow mosaic disease (YMD) is the most devastating disease of soybean under north Indian conditions. A recombinant inbred line population derived from SL 958 (R) × AGS 456 (S) was used to map the genes imparting YMD resistance. Genotyping by sequencing (GBS) of 148 individuals and the parents was used to identify polymorphic SNPs in the population. These were used to generate linkage maps and subsequently map the QTL. A QTL, MYMIV 1-1.1, was mapped onto chromosome 6. The QTL was mapped at a genetic distance of 114.31 cM, with likelihood ratio of 81.34 (LOD 17.68), explaining 33.80% of the variation for the trait, with an additive effect of 1.22. MYMIV 1-1.1 was flanked by SNPs Gm06_12614920 explaining 33.80% of variation and Gm06_12887789 explaining 31.04% of the variation. The QTL region spanned for a total of 2.798 Mbp. The QTL was mapped in an approximately 4 cM region. Flanking SNPs can be developed into linked markers for effective marker-assisted selection. Out of the genes in the QTL region, Glyma.06G161700 (Suppressor of Gene Silencing/SGS3) is the strongest contender for the resistance gene. This is the first study documenting GBS-based mapping of YMD resistance in soybean. © 2024 Society of Chemical Industry.

Molecular diversiry studies among blackgram genotypes for yellow mosaic virus resistance

Yellow mosaic disease (YMD), incited by a geminivirus. Mungbean Yellow Mosaic Virus (MYMV), is transmitted by whiteflies, poses a significant threat to various leguminous crops in India. This study focuses on identifying resistant sources and validating molecular markers for their efficacy in detecting YMV resistance in blackgram. In the present study, 150 blackgram genotypes were evaluated to identify resistant sources for YMD under natural field conditions and through molecular markers. Among the 150 genotypes, 22 (both resistant and susceptible) were selected based on field screening. These genotypes were validated using 15 molecular markers, including 8 simple sequence repeats (SSRs) and 7 gene-specific markers linked to MYMV resistance. The markers amplified a total of 48 alleles, with polymorphic information content (PIC) values ranging from 0.82 (CEDG67) to 0.21 (HSP), with an average value of 0.55. The highest PIC values were exhibited by markers CEDG67 (0.82), CEDG115 (0.81), and CEDG20 (0.74). Cluster analysis using DARWIN revealed that most phenotypically resistant genotypes grouped together, while susceptible genotypes formed separate clusters. The genotypes LBG 904, LBG 932, LBG 884, PU 1815, PU 1808, PU 1803, MASH 1008, MASH 114, VBN 10, and PU 31 exhibited resistance to YMV phenotypically. Among these, LBG 904, LBG 932, PU 1815, PU 31, and MASH 1008 produced a 162 bp resistant allele using the marker CEDG180. Similarly, the gene-specific marker DEF produced a 190 bp resistant allele in all the resistant genotypes, whereas the susceptible genotypes produced both 190 and 250 bp alleles. These identified genotypes can serve as valuable sources for MYMV resistance in blackgram breeding programs. Keywords: SSR markers, Blackgram, Diversity, MYMV

Improving Pepper Inbreds for Resistance to Pepper Yellow Leaf Curl Thailand Virus (PepYLCTHV) through Challenged Inoculations

Chili peppers (Capsicum annuum L.) are an economically important crop worldwide. Pepper yellow leaf curl Thailand virus (PepYLCTHV), a Begomovirus causing yellow leaf mosaic disease of chili pepper, has been reported to incur 95% economic loss under epiphytotic conditions. Thirty-one chili genotypes were screened for resistance to PepYLCTHV disease through inoculation using 10–15 viruliferous whiteflies per plant. We purified two resistant lines (PEP6 and PEP12) through four generations of selfing and selection. At 28 days after inoculations, two chili genotypes (PEP6 and PEP12) had low disease severity and percentage of disease incidence (DI) compared to four susceptible checks, viz., Yodsonkeam80, Homsupan, Huareau12, and Pong Charian, which had a disease severity score of 5 with 100% DI. Thirty initial plants of PEP6 showed an average disease severity of 3.64 with 69.33% DI, and PEP12 showed an average disease severity of 3.83 with 77.67% DI. From these populations, we selected nine highly resistant plant of PEP6 and seven plants of PEP12 having a disease severity of 0 through pure-line selection for four selfing generations. The ratio of resistance (R) to susceptibility (S) consequently decreased. In PEP6, the ratio decreased from 1R:2S to 1R:1S, while in PEP12 the ratio decreased from 1R:3S to 1R:1S. These lines have potential for release as resistant lines for improving chili pepper resistance to PepYLCTHV and for developing makers associated with the resistant trait.

Identifying sources of yellow mosaic disease resistance in moth bean under arid field conditions

. KEYWORDS :Arid legume, moth bean, MYMV, pre breeding, YMD, YMV

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.

Molecular Characterization and Pathogenicity of Groundnut Bud Necrosis Virus (Orthotospovirus arachinecrosis) Inducing Necrosis in Black Gram

Orthotospovirus arachinecrosis commonly known as Groundnut bud necrosis virus (GBNV), is the causal agent for necrosis disease in black gram. GBNV is the second most important challenge to black gram production in major growing areas following yellow mosaic disease. Symptoms of necrosis disease of black gram include severe downward curling and twisting of leaf lamina, veinal necrosis, petiole necrosis, bud necrosis, and necrotic streaks on the stem. Infection at early growth stages of black gram leads to plant death, while surviving plants exhibited stunted growth with a significant reduction in pod yield. The GBNV-BG isolate was maintained in pure form on cowpea cv. C-152, resulted in chlorotic and necrotic local lesions on primary leaves at seven days post-inoculation. The pathogenicity of GBNV on black gram (LBG-645) was further confirmed by artificial sap inoculation. Amplification of the coat protein gene of GBNV was confirmed through RT-PCR using gene-specific primers, producing an amplicon of 800 bp. Sequence analysis of the coat protein gene revealed that the present study isolates OQ683310 and OR295403 shared sequence identity of 98.0 % and 99.3 % respectively at the nucleotide level, with other isolates in the NCBI database. The phylogenetic analysis of the coat protein gene revealed that the isolates under this study were closely linked with the GBNV tomato isolate from Tamil Nadu (MN718651 and MZ505083).

Progress in genomic-driven breeding for improving the disease and insect pest resistance in black gram (Vigna mungo)

Urdbean or black gram (Vigna mungo) is a short-duration pulse crop with a high nutritional profile, and its main cultivation areas are in South and Southeast Asia, including India. The production of black gram is constrained by various biotic stresses, particularly diseases like yellow mosaic disease, leaf crinkle disease, and powdery mildew. Additionally, insect pests like bruchids and pod borers also affect black gram production. These biotic stresses cause significant losses in yield and reduce yield quality. Breeding for resistance is the most desirable and economical approach for the management of diseases and insect pests. In the past, conventional approaches used in black gram breeding contributed to improving resistance to biotic stress in black gram, but the success was not at the desired level. Therefore, to enhance biotic stress resistance, the black gram breeding programs shifted their focus toward genomics. Recently, several genomics resources, including genome and transcriptome sequences, DNA markers, and genetic linkage maps, have been developed exclusively for the black gram. However, the progress of improving black gram resistance to biotic stress using these genomic resources is still very slow. In this review, we discuss the black gram genomic resources and their use in breeding programs for developing biotic stress resistance. In addition, we discuss the existing research gaps and offer our view on future research for combating the biotic stress in black gram.

Exploring intra-allelic and inter-allelic gene interactions influencing seed yield and its components in inter-varietal crosses of Mungbean (Vigna radiata (L.) Wilczek)

Mungbean (Vigna radiata (L.) Wilczek) is a versatile legume widely cultivated for its nutritional value and adaptability. Meeting the increasing global demand for nutritious food requires the development of high-yielding varieties. Therefore, understanding the inheritance of yield and component traits is crucial for defining effective breeding strategies. In the present study, we aimed to investigate the genetic effects and interactions governing inheritance through generation mean analysis. The four crosses viz., IPM409-4×VGG18-002, IPM409-4×WGG42, COGG13-39×VGG16-058 and COGG13-39×VGG18-002 and their five generations (P1, P2, F1, F2, and F3) were evaluated for nine yield and yield component traits during 2023 summer season. The significance of additive, dominance, and epistatic components viz.,additive×additive [i] and dominance×dominance [l] of each trait was found to be different among all the crosses. Mungbean is a self-pollinated crop, so only fixable gene effects can be exploited for trait improvement. In the IPM409-4×VGG18-002 cross, all the traits exhibited additive or additive × additive gene action except for plant height and seed yield per plant (dominance). The scaling test was significant in IPM409-4×WGG42 cross for all the traits, except for the number of pods per cluster. Except for the number of branches per plant in which the dominance effect was evident, additive or additive×additive gene effects were observed for the other traits. In COGG13-39×VGG16-058 and COGG13-39×VGG18-002 crosses, all the yield traits recorded fixable (additive and additive×additive) gene effects except for number of pods per plant in COGG13-39×VGG18-002. Considering the results of all four crosses, gene actions that exhibit consistency across crosses revealed that epistatic interaction (additive×additive) significantly influenced the expression of various mung bean traits. Therefore, the later generation selection of short-duration segregants with high yield, bold seeds, and resistance to yellow mosaic disease from the above populations can be carried out to develop commercially valuable mung bean varieties.

Designing of an Innovative Multiplex Model to Control Insects/Pests (Whitefly) in Okra Crop Fields and Assessment for its Efficacy in Control Viral Diseases

Whitefly (Bemisia tabaci) destroys a great proportion of crops in India. Whitefly is the carrier of begomovirus which causes okra yellow vein mosaic viral disease. Preventing the pest infestation without the use of chemical fertilizers and pesticides is the need of the hour. Integrated Pest Management (IPM) involves strategies that maintain pest population below Economic Injury Level (EIL). In the present study a multiplex insect catching trap was constructed with the aim of controlling pest infestation in a sustainable and eco-friendly manner. The multiplex trap was prepared using yellow sticky papers and Methyl Eugenol pheromone as an insect/pest attractant. The traps were placed in field and thereafter plants were tested for the presence of viral DNA using PCR. The fields in which traps were placed showed negligible or few instances of viral infection while the fields in which no traps were placed showed considerable virus infection. Additionally, the fields with the trap showed a higher yield percentage of crop compared to the field with no trap.

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

Molecular characterization of recombinant citrus yellow mosaic badnavirus infecting Coorg mandarin exhibiting yellow mosaic disease symptoms in high humid tropic region of Western Ghats.

The online version contains supplementary material available at 10.1007/s13337-024-00864-z.

First record of tomato leaf curl Kerala virus and betasatellite associated with yellow vein mosaic disease of beet root (Beta vulgaris L. ssp. vulgaris) in India

First record of tomato leaf curl Kerala virus and betasatellite associated with yellow vein mosaic disease of beet root (Beta vulgaris L. ssp. vulgaris) in India

Viral complexity of tomatoes yellow mosaic and leaf curl diseases in lowland and highland areas

AbstractYellow mosaic and leaf curl diseases caused by whitefly‐transmitted begomo virus genera are important problems in tomato (Solanum lycopersicon L.) production in Indonesia, particularly on Java Island. The aims of this survey are to assess the percentages of disease incidence (DI) and disease severity index (DSI), evaluate the spread and complexity of begomovirus and crinivirus infections responsible for yellow mosaic and leaf curl diseases in tomato plants, and identify the species of whitefly insect vectors and their cryptic biotypes in tomato production centers located on Java Island, Indonesia. A total of 43 locations in East, Central, and West Java were surveyed during the dry season from July 2022 to September 2022. Disease incidence and severity were determined by observing 200 samples of tomato plants from five points at each location, with 40 plants per point of land. A total of 116 whitefly samples in microtubes and 215 symptomatic leaf samples were collected. The genus begomovirus and crinivirus infecting tomato were identified by PCR and RT‐PCR using genus‐specific primers. Similarly, whitefly species and their cryptic biotypes were identified by PCR using MCoI gene‐specific primers. Results showed that DI and DSI remarkably differed between the lowlands (66%–89%) and highlands (33%–62%) in the provinces of Central Java and West Java. Furthermore, PCR analysis of 215 infected tomato showing the symptoms of yellow mosaic and curly leaf revealed that three begomoviruses, one crinivirus and their mixed combination both begomoviruses, one crinivirus has been detected in all the samples. Similarly, the whitefly insect vector Bemisia tabaci biotype Q was identified in all areas, whereas Trialeurodes vaporariorum was found only in the East Java and Java highlands, respectively.

Identification of new stable resistant sources and assessing agro-morphological performance of sponge gourd germplasm against Tomato Leaf curl New Delhi Virus incidence.

Tomato leaf curl New Delhi virus (TolCNDV) causes yellow mosaic disease, which poses a significant biotic constraint for sponge gourd cultivation, potentially resulting in crop loss of up to 100%. In the present investigation, 50 diverse genotypes were screened for 3 years under natural epiphytotic conditions. A subset of 20 genotypes was further evaluated across four different environments. The combined analysis of variance revealed a significant genotype × environment interaction. Eight genotypes consistently exhibited high and stable resistance in the preliminary screening and multi-environment testing. Furthermore, genotype plus genotype × environment interaction biplot analysis identified DSG-29 (G-3), DSG-7 (G-2), DSG-6 (G-1), and DSGVRL-18 (G-6) as the desirable genotypes, which have stable resistance and better yield potential even under diseased conditions. The genotype by yield × trait biplot analysis and multi-trait genotype-ideotype distance index analysis further validated the potential of these genotypes for combining higher yield and other desirable traits with higher resistance levels. Additionally, resistant genotypes exhibited higher activities of defense-related enzymes as compared to susceptible genotypes. Thus, genotypes identified in our study will serve as a valuable genetic resource for carrying out future resistance breeding programs in sponge gourd against ToLCNDV.

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.

Studies on the transmission of Squash Leaf Curl China Virus causing yellow mosaic and leaf curl disease in pumpkin

Viruses pose a significant threat to pumpkin cultivation, leading to substantial yield losses and reduced fruit quality. Understanding the transmission dynamics and disease progression of Squash Leaf Curl China Virus (SLCCV), a major virus affecting pumpkin, will contribute to developing effective management strategies for this crop. Our study aimed to develop an efficient mechanical inoculation method for SLCCV in pumpkin and investigate whitefly transmission. Mechanical inoculation was assessed using different buffers (I, II, and III) for preparing the viral inoculum. Buffer III, consisting of phosphate buffer, β-mercaptoethanol, and Na2SO3, showed the highest severity of symptoms and incidence of infection in the susceptible pumpkin variety Pusa Vishwas. The summer season was the most favourable for virus transmission, and plant parts such as expanded leaves, middle leaves, and stems exhibited higher infectivity than other parts. A minimum of two whiteflies per plant successfully transmitted the virus to pumpkin plants, resulting in yellow mosaic symptoms and stunted growth. The transmission efficiency increased with an increase in number of whiteflies per plant. A minimum acquisition access feeding period (AAP) of 10 min. and an inoculation access feeding period (IAP) of 24 h were optimal for whitefly-mediated transmission of SLCCV. These findings highlight the importance of vector control strategies, such as insecticides and physical barriers to prevent whitefly-mediated transmission of SLCCV in pumpkin. This is the first report of sap transmission of SLCCV in pumpkin, emphasizing the importance of developing and implementing comprehensive control strategies that address all possible routes of infection.

Agronomic evaluation of introgressed lines developed for yellow vein mosaic disease resistance in okra (Abelmoschus esculentus L. Moench)

Agronomic evaluation of introgressed lines developed for yellow vein mosaic disease resistance in okra (Abelmoschus esculentus L. Moench)