CHARACTERIZATION OF PEPPER MILD MOTTLE VIRUS STRAINS AND EVALUATION OF RESISTANCE IN CAPSICUM

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dc.contributor.advisorSharma, P.N.
dc.contributor.authorNidhi Kumari
dc.date.accessioned2019-01-23T09:02:09Z
dc.date.available2019-01-23T09:02:09Z
dc.date.issued2018-06
dc.description.abstractCapsicum (Capsicum annuum L. var.grossum Sendt) is an important spice and vegetable crop being cultivated worldwide. More than 20 viruses are known to infect Capsicum spp. across the world and Pepper mild mottle virus (PMMoV), a member of Virgaviridae family and Tobamovirus genus is emerging as a great threat to the capsicum cultivation both in protected and open conditions in Himachal Pradesh (H.P.). The present study on PMMoV was undertaken to identify the pathotype of PMMoV prevalent in H.P., production of polyclonal antiserum against PMMoV-CP expressed in E. coli, evaluation of resistance against PMMoV in capsicum and identification of attenuated/mild strain if any. Surveys conducted to assess the prevalence of mild mottle disease showed wide occurrence of the disease and out of 97 samples collected during surveys, 54 showed the presence of PMMoV in DAS-ELISA with maximum percentage of positive samples from district Kullu (88.89%) followed by Mandi (78.57%) district. The presence of PMMoV was confirmed through RT-PCR using coat protein (CP) specific primers where positive samples yielded amplification of ~743 bp. Isolates were selected for varaiblity assays on differential varieties of capsicum and CP gene sequence analysis. All the isolates produced symptoms like mosaic, color variations, leaf cupping, vein banding on susceptible cultivar California Wonder. Based on the pathogenic reaction on differential varieties and amino acid sequence of CP gene, all the test isolates were grouped and identified as pathotype P12 which can overcome L+, L1 and L2 resistance alleles. For production of polyclonal antiserum, the PMMoV-CP was over-expressed in E. coli using IPTG at 1mM final concentration with overnight incubation in shaking incubator at 16oC which resulted in induction of target recombinant protein with molecular weight ~26kDa. The antiserum generated through out sourcing, evaluated for its sensitivity and specificity through Western blot and DAC-ELISA. In Western blot assay, the test antiserum reacted strongly both with PMMoV-CP in purified protein and native CP in crude sap from PMMoV infected pepper plants, whereas no reaction was observed with healthy plant sap. In DAC-ELISA antiserum dilution up to 1:1000 was capable of differentiating the PMMoV infected sample from healthy samples. The antiserum did not react with other capsicum viruses viz., Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Pepper veinal mottle virus (PVMoV), Potato virus Y (PVY) and Tomato yellow leaf curl virus (TYLCV) antigen. Only two exotic capsicum accessions PI-159236 and PI-260429 were found resistant to PMMoV. None of the isolates showed the characteristics of attenuated/mild strain as all the isolates produced prominent symptoms on susceptible cv- California Wonder.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810092126
dc.keywordsCapsicumen_US
dc.language.isoenen_US
dc.pages108en_US
dc.publisherCSKHPKV, Palampuren_US
dc.subPlant Pathologyen_US
dc.subjectnullen_US
dc.themeEvaluation of resistance in capsicumen_US
dc.these.typePh.Den_US
dc.titleCHARACTERIZATION OF PEPPER MILD MOTTLE VIRUS STRAINS AND EVALUATION OF RESISTANCE IN CAPSICUMen_US
dc.typeThesisen_US
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