​RCA-based Detection of Begomoviruses in Weed Ggenera Associated with Legumes in Southern Karnataka

Author(s):  
Sudeep Pandey ◽  
T.R. Girish ◽  
S. Basavaraj ◽  
A.S. Padmaja ◽  
N. Nagaraju

Background: Yellow mosaic disease (YMD) caused by begomoviruses transmitted through the insect vector Bemisia tabaci poses a serious threat to the production of legume crops. Methods: Season-long surveys were carried out for YMD occurrence in six different legume crops and associated natural weeds both symptomatic and asymptomatic across the districts of southern Karnataka, India. The samples were analyzed through RCA PCR using specific primer pairs. Result: Up to 94.1 per cent YMD incidence was recorded and nine weed species were commonly found associated with legume crops. The weeds viz., Ageratum conyzoides, Alternanthera sessilis, Commelina benghalensis and Euphorbia geniculata were abundantly found in the surveyed regions. The weeds were both symptomatic and asymptomatic. Rolling circle amplification coupled polymerase chain reaction method was employed to detect yellow mosaic virus in asymptomatic weeds. Phylogenetic analysis based on the sequences of PCR amplified products of weeds and symptomatic legumes revealed a close clustering of the weed samples with horsegram yellow mosaic virus, legume yellow mosaic virus and mungbean yellow mosaic virus. Overall, our data suggests the role of weed species associated with legume crops as alternative/collateral hosts of begomoviruses and their role in the epidemiology of yellow mosaic disease.

Author(s):  
Sudeep Pandey ◽  
T.R. Girish ◽  
S. Basavaraj ◽  
A.S. Padmaja ◽  
N. Nagaraju

Background: Yellow mosaic disease (YMD) caused by begomoviruses transmitted through the insect vector Bemisia tabaci poses a serious threat to the production of legume crops. Methods: Season-long surveys were carried out for YMD occurrence in six different legume crops and associated natural weeds both symptomatic and asymptomatic across the districts of southern Karnataka, India. The samples were analyzed through RCA PCR using specific primer pairs. Result: Up to 94.1 per cent YMD incidence was recorded and nine weed species were commonly found associated with legume crops. The weeds viz., Ageratum conyzoides, Alternanthera sessilis, Commelina benghalensis and Euphorbia geniculata were abundantly found in the surveyed regions. The weeds were both symptomatic and asymptomatic. Rolling circle amplification coupled polymerase chain reaction method was employed to detect yellow mosaic virus in asymptomatic weeds. Phylogenetic analysis based on the sequences of PCR amplified products of weeds and symptomatic legumes revealed a close clustering of the weed samples with horsegram yellow mosaic virus, legume yellow mosaic virus and mungbean yellow mosaic virus. Overall, our data suggests the role of weed species associated with legume crops as alternative/collateral hosts of begomoviruses and their role in the epidemiology of yellow mosaic disease.


2018 ◽  
Vol 1 (2) ◽  
pp. p100
Author(s):  
Md. S. Islam ◽  
Md. B. Hossain ◽  
Saleh A. Shahriar ◽  
Fatema Begum ◽  
Md. N. H. Sani

The prime aim of the study was to manage of Yellow mosaic disease of mungbean against Mungbean yellow mosaic virus (MYMV) by using one newly release botanical nutrient and through three selected insecticides. BARI (Bangladesh Agricultural Research Institute) released variety BARI mung-5, three insecticides (Imidacloprid, Acmix and Sobicron) and one botanical nutrient PPN (Peak performance nutrients) were used in the experiment. The plants were grown for pulse production and natural inoculums were relied upon for the infection of MYMV. Growth parameters, yield attributes and physiological features were significantly influenced by the application of selected insecticides and PPN combinations. Disease incidence and disease severity of MYMV were significantly varied among the treatments. Application of Imidacloprid with PPN combination gave the lowest disease incidence (3.13, 5.24 and 6.24% per plot and 14.33, 15.49 and 21.87% per plant) at 30, 40 and 50 DAS, respectively while the highest disease incidence (7.77, 13.70 and 19.24% per plot and 39.33, 48.20 and 56.63% per plant) were found in control at 30, 40 and 50 DAS, respectively. Application of Imidacloprid with PPN also gave the lowest disease severity (5.00, 6.00 and 13.33% at 30, 40 and 50 DAS, respectively while the highest disease severity (27.33, 35.00 and 45.00%) at 30, 40 and 50 DAS, respectively were measured in control treatment when no insecticides and PPN was used. If the disease is established once in the field then it is difficult to manage. As the disease is transmitted by vector (whitefly), the growers are suggested to control the vector populations before reaching economic damage and severe disease infection.


2019 ◽  
Vol 17 (04) ◽  
pp. 362-370
Author(s):  
Nagaraj ◽  
S Basavaraj ◽  
A.S. Padmaja ◽  
N Nagaraju ◽  
S Ramesh

AbstractYellow mosaic disease (YMD) caused by mungbean yellow mosaic virus (MYMV) is one of the most destructive biotic production constraints in mungbean. Development and introduction of resistant cultivars are considered as the most economical and eco-friendly option to manage YMD, for which availability of stable sources of resistance is a pre-requisite. A set of 14 mungbean genotypes including a susceptible check were evaluated for responses to YMD under natural infection across three seasons and under challenged inoculation in glasshouse for one season. None of the genotypes were immune to YMD and produced different degrees of response to MYMV in terms of yellow mosaic symptoms (YMS). Based on the delayed appearance of initial YMS, and lower estimates of per cent disease index and area under disease progressive curve (AUDPC) in response to natural infection and challenged inoculation, five genotypes namely AVMU 1698, AVMU 1699, AVMU 16100, AVMU 16101 and KPS 2 were identified as resistant to YMD. Failure of detection of MYMV through polymerase chain reaction (PCR) using MYMV coat protein gene-specific primer and successful detection of the same through rolling circle amplification-PCR suggested latent infection of MYMV in resistant genotypes. The resistance response of the five genotypes could be attributed to enhanced activities of enzymes such as peroxidase, polyphenol oxidase and phenylalanine ammonia lyase and increased concentration of total phenols. These results are discussed in relation to strategies to breed mungbean for resistance to YMD.


Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 622 ◽  
Author(s):  
Chandra Mohan Singh ◽  
Poornima Singh ◽  
Aditya Pratap ◽  
Rakesh Pandey ◽  
Shalini Purwar ◽  
...  

Yellow mosaic disease (YMD) affects several types of leguminous crops, including the Vigna species, which comprises a number of commercially important pulse crops. YMD is characterized by the formation of a bright yellow mosaic pattern on the leaves; in severe forms, this pattern can also be seen on stems and pods. This disease leads to tremendous yield losses, even up to 100%, in addition to deterioration in seed quality. Symptoms of this disease are similar among affected plants; YMD is not limited to mungbean (Vigna radiata L. Wilczek) and also affects other collateral and alternate hosts. In the last decade, rapid advancements in molecular detection techniques have been made, leading to an improved understanding of YMD-causing viruses. Three distinct bipartite begomoviruses, namely, Mungbean Yellow Mosaic India Virus (MYMIV), Mungbean Yellow Mosaic Virus (MYMV), and Horsegram Yellow Mosaic Virus (HgYMV), are known to cause YMD in Vigna spp. Vigna crops serve as an excellent protein source for vegetarians worldwide; moreover, they aid in improving soil health by fixing atmospheric nitrogen through a symbiotic association with Rhizobium bacteria. The loss in the yield of these short-duration crops due to YMD, thus, needs to be checked. This review highlights the discoveries that have been made regarding various aspects of YMD affecting mungbean, including the determination of YMD-causing viruses and strategies used to develop high-yielding YMD-resistant mungbean varieties that harness the potential of related Vigna species through the use of different omics approaches.


Author(s):  
Vallabhaneni Tilak Chowdary ◽  
V. Manoj Kumar ◽  
P. Kishore Varma ◽  
B. Sreekanth ◽  
V. Srinivasa Rao

Background: Yellow mosaic disease (YMD) caused by Yellow mosaic virus is one of the major constraints in the pulse production in Andhra Pradesh (A.P.) due to fast evolution of strains, like Mungbean yellow mosaic India virus (MYMIV). Keeping this in view, a survey was undertaken in the major blackgram growing districts of A.P. to know the YMD incidence in blackgram and weed hosts and were characterized based on genetic features by comparing with other YMV isolates from different hosts and locations across the world. Methods: Roving survey was conducted during rabi 2019-20 in major blackgram growing districts of A.P. viz., Krishna, Guntur, West Godavari and Prakasam districts for YMD incidence. Blackgram plants showing characteristic symptoms were collected as representative samples from each mandal along with the suspected weed plants and were subjected to amplification using coat protein (CP) specific primers followed by molecular characterization. Phylogenetic tree for coat protein (CP) gene was constructed using aligned sequences with 1000 bootstrap replicates following neighbor-joining phylogeny. Result: Out of the four districts surveyed, the highest disease incidence was recorded at Machavaram village of Prakasam district (43.22%), whereas least disease incidence was recorded at Chinaganjam village of Praksam district (2.4%). Six weeds viz., Ageratum conyzoides, Amaranthus viridis, Parthenium hysterophporus, Vigna trilobata, Abelmoscus moschatus, Desmodium laxiflorum have showed positive result in PCR amplification with MYMIV specific coat protein primers. Four isolates from blackgram samples and two from weed plants shared 94.85 to 99.58% nucleotide identity among themselves.


Author(s):  
Hélène Pidon ◽  
Neele Wendler ◽  
Antje Habekuβ ◽  
Anja Maasberg ◽  
Brigitte Ruge-Wehling ◽  
...  

Abstract Key message We mapped the Rym14Hb resistance locus to barley yellow mosaic disease in a 2Mbp interval. The co-segregating markers will be instrumental for marker-assisted selection in barley breeding. Abstract Barley yellow mosaic disease is caused by Barley yellow mosaic virus and Barley mild mosaic virus and leads to severe yield losses in barley (Hordeum vulgare) in Central Europe and East-Asia. Several resistance loci are used in barley breeding. However, cases of resistance-breaking viral strains are known, raising concerns about the durability of those genes. Rym14Hb is a dominant major resistance gene on chromosome 6HS, originating from barley’s secondary genepool wild relative Hordeum bulbosum. As such, the resistance mechanism may represent a case of non-host resistance, which could enhance its durability. A susceptible barley variety and a resistant H. bulbosum introgression line were crossed to produce a large F2 mapping population (n = 7500), to compensate for a ten-fold reduction in recombination rate compared to intraspecific barley crosses. After high-throughput genotyping, the Rym14Hb locus was assigned to a 2Mbp telomeric interval on chromosome 6HS. The co-segregating markers developed in this study can be used for marker-assisted introgression of this locus into barley elite germplasm with a minimum of linkage drag.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256449
Author(s):  
Muhammad Younas ◽  
Huasong Zou ◽  
Tasmia Laraib ◽  
Nasir Ahmad Rajpoot ◽  
Nasir Ahmad Khan ◽  
...  

Mungbean yellow mosaic virus (MYMV) is an important constraint in successful production of mungbean (Vigna radiata L.) in many countries, including Pakistan. The MYMV spreads by insect vector whitefly (Bemisia tabaci Gennadius). The use of resistant cultivars is the most effective management tactics for MYMV. Twenty mungbean varieties/lines were screened against insect vector of MYMV under field condition in the current study. Resistance levels for varieties/lines were assessed through visual scoring of typical disease symptoms. Furthermore, the impacts of two insecticides ‘Imidacloprid’ and ‘Thiamethoxam’ and two plant extracts, i.e., neem (Azadirachta indica), and Eucalyptus (Eucalyptus camaldulensis) were tested on the suppression of whitefly. Field screening indicated that none of the tested varieties/lines proved immune/highly resistant, while significant variations were recorded among varieties/lines for resistance level. All varieties/lines were systemically infected with MYMV. The varieties ‘AARI-2006’ and ‘Mung-14043’ were considered as resistant to MYMV based on visual symptoms and the lowest vector population. These varieties were followed by ‘NM-2006’ and ‘NL-31’, which proved as moderately resistant to MYMV. All remaining varieties/lines were grouped as moderately to highly susceptible to MYMV based on visual symptoms’ scoring. These results revealed that existing mungbean germplasm do not possess high resistance level MYMV. However, the lines showing higher resistance in the current study must be exploited in breeding programs for the development of resistant mungbean varieties/lines against MYMV. Imidacloprid proved as the most effective insecticide at all concentrations to manage whitefly population. Therefore, use of the varieties with higher resistance level and spraying Imidacloprid could lower the incidence of MYMV.


Author(s):  
K. Kamesh Krishnamoorthy ◽  
V. G. Malathi ◽  
P. Renukadevi ◽  
S. Mohan Kumar ◽  
M. Raveendran ◽  
...  

The yellow mosaic disease of blackgram caused by Mungbean yellow mosaic virus has emerged as a serious threat to pulses production especially in the South Eastern Asia.  Seed borne nature of MYMV in blackgram seeds was determined using the seeds harvested from a MYMV resistant (either VBN-6 or VBN-8) and susceptible blackgram (CO-5) varieties grown 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 60 days after sowing (DAS). Seed borne nature of MYMV was observed only in the susceptible variety CO-5 and was absent in the   resistant varieties. Transmission of MYMV from infected plant to seeds was observed in all the three parts of the seeds viz., seed coat, cotyledon and embryo. Seeds from infected plants also showed abnormalities like shrinking, discolouration, ill filling inside pods and misshapen appearance.


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