<div><strong>Background: </strong>Cowpea [<em>Vigna unguiculata</em> (L) Walp.] is one of the Paraguayan rural families&rsquo; main crops, serving as an essential protein and carbohydrate source. Cowpea aphid borne mosaic virus (CABMV) and cowpea severe mosaic virus (CPSMV) were identified infecting cowpea plants. Disease control caused by both viruses is difficult because there is no information about local cowpea resistant cultivars and vector control is not practical.<br />
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<strong>Methods:&nbsp;</strong>In the present work, sixteen cowpea genotypes/cultivars were mechanically inoculated with local isolates of CABMV and CPSMV to identify resistant genotypes/cultivars that can be used in breeding programs. Virus infections were determined by symptoms expression and confirmed by PTA-ELISA.<br />
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<strong>Result:&nbsp;</strong>Genotypes Arroz rojo (<em>V. angularis</em>), TVu 379, TVu 382, TE94-256-2E and TE97-309G-9 were resistant to CABMV. Genotypes Arroz rojo (<em>V. angularis</em>), CNCX-698-128F, TVu 379, TVu 382, TVu-3961, TE97-309G-9 and TE97-309G-3 were resistant to CPSMV. Overall, this study showed that local cowpea cultivars do not offer any resistance to virus infection and the need for resistant germplasms for cowpea breeding programs in the country.</div>


<p>​​Screening Cowpea Genotypes for Resistance to Cowpea Aphid Borne Mosaic Virus (CABMV) and Cowpea Severe Mosaic Virus (CPSMV) in Paraguay</p>


<div style="text-align: justify;">The present research was carried out to investigate the genetic diversity among cowpea tolerant and susseptibe genotypes. For which the fifteen cowpea genotypes were manually infected with Cowpea yellow mosaic virus(CYMV) &nbsp;inoculum and &nbsp;to detect virus by a serological technique. &nbsp;The five most tolerant and sensitive each genotypes had been taken for genetic diversity study in which JCPL-2 and JCPL-11 was found most susceptible and tolerant genotype, having absorbance at 405nm 2.172 and 0.167 respectively. The RAPD, ISSR and SSR marker system were applied to the ten cowpea genotypes. For the RAPD data, based on PIC value, it can be said that primer OPAI-15 was the best primer resulting good amplification with maximum PIC value (0.764).Dendrogram constructed using the RAPD data clearly distinguished all genotypes. It revealed that JCPL-44 and JCPL-45 found in one cluster and shared maximum 96.00% similarity; however, genotype JCPL-2 have out grouped from other 9 genotypes and shared minimum 41.00% similarity. In case of ISSR data, based on PIC value it can be said that the primer 835 was the best primer resulting good amplification with maximum PIC value (0.837). Jaccard&rsquo;s similarity coefficient ranged from 0.625 and 0.906. The ISSR results indicated that maximum similarity 90.60% was found between JCPL-2 and JCPL-18, while minimum similarity 62.50% was obtained between JCPL-2 and JCP- 87. For the SSR data, based on PIC value it can be said that the primer VM-13 was the best primer resulting good amplification with maximum PIC value (0.668). Jaccard&rsquo;s similarity coefficient ranged from 0.500to 1.000. So SSR data revealed that JCPL-2 showed maximum variability compared to other nine genotypes. The combined RAPD, ISSR and SSR analysis revealed that out of ten genotypes JCPL-44 and JCPL-45 were showed maximum (91.0%) similarity. The lowest similarity of 58.30% was found between JCPL-2 and JCP-45.</div>

Characterization and genetic diversity of cowpea (<em>Vigna unguiculata</em> L.) genotypes linked to Cowpea yellow mosaic virus

<div style="text-align: justify;">Cowpea mosaic virus (CpMV) is known to cause yield loss of as much as 80-100 per cent. Among different approaches available in the management of this disease development and release of resistant varieties is the most viable option for farmers. Hence an investigation was carried out to study the inheritance of resistance to cowpea mosaic virus (CpMV) and to identify DNA markers linked to genomic regions conferring resistance to CpMV. The resistance was found to be governed by single recessive gene in the 191 F2:3 progenies derived from the cross C-152 (susceptible) &times; V-57817 (resistant). &nbsp;Single marker analysis with 191 F2 individuals and 106 polymorphic SSR markers indicated that two markers, MA15 and MA80 were linked to CpMV resistance as evidenced by significant mean sum of squares due to between marker classes and putative linkage of these markers for resistance to CpMV was confirmed by bulked segregant analysis. Through linkage map constructed utilizing 91 polymorphic SSR markers it was possible for us to show that the two markers MA15 and MA80 were included in the linkage group 6 and the marker gene was likely to be present between these markers. Marker assisted backcrossing was practiced to transfer resistance gene in to an agronomically superior variety C-152.</div>

Genetic analysis and marker assisted backcrossing for transfer of mosaic virus resistance in cowpea [<em>Vigna unguiculata</em> (L.) Walp.]

<div style="text-align: justify;">One hundred cowpea genotypes were screened against Bean common mosaic virus (BCMV) by artificial inoculation genotypes. The genotypes showed different disease reaction viz., immune, resistant, moderately resistant, Sap moderately susceptible, susceptible and highly susceptible. The SSR markers were characterized using a total of 25 randomly selected resistance and susceptible cowpea genotypes. Among, 10 SSR markers used to screen polymorphism, only 4 primers were found to be polymorphic and they were used for characterization and finding out genetic relationship of cowpea genotypes. The polymorphism information content (PIC) of these SSR markers ranged from 0.23 to 0.37 and single marker analysis (SMA) revealed, out of these 4 SSR markers M 135 marker explained 28.2 % of phenotypic variation (R2). The banding pattern of all cowpea genotypes were scored and dendrogram was constructed. A dendrogram of these genotypes based on SSR polymorphism divided into two major clusters at 35 % similarity. Cluster I was the biggest with 20 genotypes which was further separated as three sub-clusters. Whereas, 5 genotypes grouped in cluster II with two small sub-clusters. The clustering pattern of resistant and susceptible genotypes was not clear, however resistant genotypes such as V-5 and IC 8996 clustered in one group with 100 % similarity. The information provided by the identified markers would be very useful in breeding programs to select cowpea lines resistance to BCMV disease and M 135 was found to be good for rapid and accurate screening of cowpea genotypes against BCMV disease resistance.</div>

Characterization and identification of SSR markers for screening of cowpea genotypes against <em>Bean common mosaic virus</em> (BCMV) disease resistance

<strong>Background:</strong> Bean common mosaic disease (BCMD) caused by <em>Bean common mosaic virus</em> (BCMV) poses a significant threat to legume crops worldwide. BCMV, a monopartite potyvirus, has been a concern since its detection in 1917 due to its seed-borne nature. Symptoms include mosaic patterns, necrosis, stunting and yield reductions, leading to substantial economic losses in affected regions. Reverse transcription-polymerase chain reaction (RT-PCR) offers a precise and efficient method for BCMV detection, necessitating the development of specific primers for accurate diagnosis.<br />
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<strong>Methods:</strong> Specific primers (BCMV-polyp1, BCMV-coatp2 and BCMV-polyp3) were designed by aligning BCMV genome sequences and employing Primer3 software. RNA isolation from infected samples and cDNA synthesis were performed using standard protocols. RT-PCR was conducted with various annealing temperatures to optimize conditions. Primer specificity of BCMV-coatp2 primer set was confirmed <em>via </em>BLAST analysis and <em>in vivo</em> testing against closely related potyviruses. Sensitivity assays were carried out using serially diluted cDNA samples from infected tissue.<br />
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<strong>Result:</strong> The designed primers demonstrated high specificity to BCMV, with no cross-reactivity observed against closely related potyviruses. Optimization of RT-PCR conditions revealed distinct bands at an annealing temperature of 51.9&deg;C for all primer sets. Sequencing confirmed amplicon sizes (175 bp, 157 bp and 189 bp) and alignment with BCMV sequences. Sensitivity analysis showed the assay capable of detecting BCMV at concentrations as low as 0.14 ng/&mu;l. Validation with field samples confirmed the effectiveness of the primers in identifying BCMV-infected plants.

<p>RT-PCR Assay Standardization for the Diagnosis of Cowpea Infecting <em>Bean Common Mosaic Virus</em></p>


<div><strong>Background:</strong> Whitefly is one of the most destructive sucking pest in the tropical and subtropical regions of the world and causing significant crop losses directly by sucking sap from the plants and indirectly through the transmission of viral diseases specifically caused by the genus <em>Begomovirus</em>. The <em>Begomovirus</em> species <em>viz</em>., <em>Mungbean yellow mosaic India virus </em>(MYMIV) and <em>Mungbean yellow mosaic virus</em> (MYMV) are causing yellow mosaic virus disease in soybean, which is transmitted by whiteflies. The disease accounts to 30-70 per cent yield loss and increases up to 80 - 100 per cent during severe incidence. Hence, there is a need for development of integrated pest management strategies against disease and whiteflies, for this the knowledge on virus-vector relationship is required. But, the studies on biological relationship of yellow mosaic virus disease and whitefly in soybean are scarce. At this juncture, considering the importance of disease in soybean, the present investigation was carried out to know the virus -vector relationship of the YMV and whitefly in soybean.<br />
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<strong>Methods: </strong>The experiment on virus-vector relationship of yellow mosaic virus and whitefly in soybean was conducted at Department of Entomology, College of Agriculture, G. B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand during 2016-17. The data on number of whiteflies per plant, acquisition and inoculation access feeding period and pre and post starvation period required for effective transmission of virus was recorded.<br />
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<strong>Result:</strong> A single viruliferous whitefly was able to transmit virus and ten viruliferous whiteflies per plant were required for cent per cent transmission of virus. The minimum acquisition access and inoculation access feeding periods required for virus transmission was 0.25h (15 min) each; while the 100 per cent virus transmission was recorded with acquisition and inoculation period of 12h, each. The per cent transmission was increased with the increase of acquisition and inoculation periods. The rate of transmission was positively correlated with pre-acquisition starvation period and negatively correlated with post- acquisition starvation period.</div>


<div>Virus Vector Relationship of Yellow Mosaic Virus and Whitefly, <em>Bemisia tabaci </em>(Gennadius) in Soybean</div>


<div><strong>Background:</strong> French bean (<em>Phaseolus vulgaris</em> L.), is one of the important legume vegetables grown in India. The disease mung bean yellow mosaic virus (MYMV) limits successful production of beans. MYMV has become an epidemic in bean growing regions, particularly in the tropical and subtropical countries. In summer, the disease is more serious and widely distributed and reported in various countries. The current study is aimed at identification of MYMV and molecular characterization of mung bean yellow mosaic virus in French bean. This study will be helpful for early detection of the virus, so that better preventive measures can be taken to control MYMV.<br />
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<strong>Methods:</strong> The investigations were conducted during 2016-2017, all the agro climatic zones of Karnataka province were surveyed. The coat protein (CP) gene of MYMV was amplified using gene specific primer with DNA isolated from MYMV infected leaves samples in french bean. Polymerase chain reaction products were Sequenced and analysed using a bioinformatic tool.&nbsp;<br />
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<strong>Result: </strong>The CP gene decrypt sequences analysis revealed that the identity and similarity in global alignment for all the obtained sequences ranging from 80.8 to 95.3% with reference to MYMV, whereas for horse gram yellow mosaic virus (HYMV) it ranges from 90.4 to 99.1%. Two distinct yellow mosaic viruses infecting french bean (MYMV and HYMV) were identified and it was observed that there exists considerable genetic variation among these species. Present work showed that the CP region is efficient enough to provide a simple, rapid and reliable method for early detection of MYMV infections in french bean, which would help to develop proper management strategies to control these viruses.</div>


<div>Identification and Molecular Characterization of Mung Bean Yellow Mosaic Virus in French Bean through Coat Protein Gene</div>


<p>Yellow mosaic virus disease is one of the major diseases of soybean in India. Genetic basis of 41 soybean genotypes varying in resistance against yellow mosaic virus was studied using 58 simple sequence repeat primers. A total of 140 alleles with an average of 2.41 alleles per locus were detected, which indicated very narrow genetic base of the genotypes studied. The polymorphic information content varied from 0.00 to 0.754 with an average of 0.357. Unweighted Pair Group Method with Arithmetic Average allocated the genotypes in 2 major clusters separated at 41% similarity with fairly good bootstrap support. Ten unique alleles observed in the study can be used for identification of genotype possessing that particular unique allele. The resistant group comprised of 21 genotypes with similarity coefficient 0.33 to 0.805, of which 20 genotypes were classified in a single sub-cluster. The results presented are of significance with regard to the identification of suitable donor parents for incorporating yellow mosaic resistance into popular soybean varieties. Genetically diverse parents with varying resistance against yellow mosaic virus identified in the study can be used for generating mapping population for the identification of SSR markers closely linked with yellow mosaic virus. &nbsp;&nbsp; &nbsp;</p>


<p>Assessment of genetic diversity of soybean genotypes differing in resistance against yellow mosaic virus using simple sequence repeat markers</p>


<div><strong>Background:</strong> In a region of Karnataka, India with a varied type climate PPSMV infection on pigeonpea occurs in a severe form and considered as green plague and one of the most devastating diseases as it appear in severe form resulting in reduction of 100% yield loss transmitted by vector eriophyid mite Aceriacajani Channabasavanna. However, not much systematic and strategic research work being carried out on epidemiology. In spite of various control measures, Sterility Mosaic Disease has continued to be major constraint in pigeonpea production. A lot of variation exists among the genetic background of different varieties in different regions. These variations render it difficult to evolve a common management strategy to control SMD epidemics. Therefore, it is necessary to know the severity of disease and factors associated with disease development which helps in devising suitable management practices.<br />
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<strong>Methods: </strong>To study the influence of sowing dates on SMD and vector population under field conditions. A total of twelve sets of sowings were made at different time interval starting from first week of January 2012 to December, 2012. The SMD disease incidence and mite population were recorded in each treatment at fifteen days interval. Under artificial environment, pigeonpea seedlings of variety ICP8863 were raised. Inoculation of virus was done at different stage of plant growth viz., 15, 30, 45, 60, 75, 90 days after sowing. The observation on terminal disease incidence was recorded at 90 DAS to study the impact of host age on SMD. The eight pigeonpea varieties were sown near the SMD infected plot so as to facilitate the movement of vector population under natural conditions to study the reaction of pigeonpea varieties to SMD. Naturally grown weeds present in and around the sterility mosaic screening nursery were collected at weekly interval to see the presence of mites. In a glass house experiment, twenty-three cultivated species of economic importance and three Nicotiana species were sown three replications to see the alternate host for the virus.<br />
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<strong>Results: </strong>The fluctuation in disease incidence and mite population was recorded throughout the year and early stage of crop growth recorded less disease incidence with lower mite population and gradual increase was recorded at later stage of crop growth period. The maximum disease incidence and mite population was recorded in crop sown during month of June and July where mean temperature was 24 to 26oC, RH 67 to 71% and rainfall of 2.13mm. The disease incidence recorded at different months of sowing had a significant positive correlation with mite population. Pigeonpea plants inoculated up to age of 30 days showed complete sterility with 100% disease incidence. The Resistant genotypes recorded less per cent disease incidence and symptom development at 60DAS. Whereas susceptible variety recorded maximum diseases incidence at early stage of crop growth and showed complete sterility. PPSMV and its vector survived on the ratooned pigeonpea plants and its wild relatives Atylosiascaraboeides during off season.</div>


<div>Epidemiological Factors Influencing the Development of Pigeonpea Sterility Mosaic Virus Disease in Pigeonpea</div>


<div style="text-align:justify"><strong>Background:</strong> <em>Vigna mungo</em> (Blackgram) is the major pulse crop cultivated in the Indian sub-continent. It is highly prone to yellow mosaic disease (YMD), which is widespread problem because all cultivated varieties are susceptible to the YMD in Andhra Pradesh state. The presence of two species of begomovirus <em>i.e.</em> Mungbean yellow mosaic virus (MYMV) and Mungbean yellow mosaic India virus (MYMIV) with YMD was reported in Andhra Pradesh. The current study was aimed to develop simple method of viral dimer clone construction and identifying the resistant blackgram genotypes against two species of begomovirus (MYMV and MYMIV) by agroinoculation technique.<br />
&nbsp;<br />
<strong>Methods:</strong> In this study, we standardize the rolling circle amplification (RCA) based viral dimer clone construction (MYMV DNA-A, MYMV DNA-B and MYMIV DNA-A) and constructed viral dimer clones were used to transform <em>Agrobacterium tumefaciens</em> EHA105 cells through freeze-thaw technique. Sprouted seed method of agroinoculation screening was conducted.<br />
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<strong>Result: </strong>Total 45 blackgram genotypes were screened by sprouted seed method of agroinoculation with two combinations of viral dimeric constructs (MYMV-TPT-A+MYMV-TPT-B and MYMIV-TPT-A+MYMV-TPT-B). Twenty four genotypes offered resistant against MYMV infection and twenty three genotypes were resistant to MYMIV infection. Total 17 genotypes offered resistance to both species of virus (MYMV andMYMIV) associated with YMD.</div>


Screening Cowpea Genotypes for Resistance to Cowpea Aphid Borne Mosaic Virus (CABMV) and Cowpea Severe Mosaic Virus (CPSMV) in Paraguay

Characterization and genetic diversity of cowpea (Vigna unguiculata L.) genotypes linked to Cowpea yellow mosaic virus

Genetic analysis and marker assisted backcrossing for transfer of mosaic virus resistance in cowpea [Vigna unguiculata (L.) Walp.]

Characterization and identification of SSR markers for screening of cowpea genotypes against Bean common mosaic virus (BCMV) disease resistance

RT-PCR Assay Standardization for the Diagnosis of Cowpea Infecting Bean Common Mosaic Virus

Virus Vector Relationship of Yellow Mosaic Virus and Whitefly, Bemisia tabaci (Gennadius) in Soybean

Identification and Molecular Characterization of Mung Bean Yellow Mosaic Virus in French Bean through Coat Protein Gene

Assessment of genetic diversity of soybean genotypes differing in resistance against yellow mosaic virus using simple sequence repeat markers

Epidemiological Factors Influencing the Development of Pigeonpea Sterility Mosaic Virus Disease in Pigeonpea

Construction of Full-length Dimer Clones of Yellow Mosaic Virus and Screening of Blackgram Germplasm using Agroinoculation