TY - BOOK AU - Sudheer K S AU - Jeeva M L (Guide) TI - Identification and characterization of viruses infecting lesser yam (Dioscorea esculenta (Lour.) Burkill) U1 - 660.6 PY - 2015/// CY - Vellayani PB - Department of Plant Biotechnology, College of Agriculture KW - Department of Plant Biotechnology N1 - MSc N2 - The study entitled “Identification and characterization of viruses infecting lesser yam (Dioscorea esculenta ( Lour. ) Burkill )” was carried out at the Division of Crop Protection, ICAR-Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Thiruvananthapuram during 2014-2015 with an aim to identify and characterize the viruses of lesser yam at molecular level and to design virus specific primers for detection. Lesser yam is a vegetatively propagated crop, grown for its high calorific value tubers. Yam viruses causing significant reduction in tuber yield and quality are poorly characterized which is restrict the international exchange of germplasm. Lesser yam leaf and tuber sample with different virus symptoms were collected from the germplasm repository and experimental fields of ICAR-CTCRI. The serological and nucleic acid based methods were employed for the detection of Yam Mild Mosaic Virus (YMMV), Yam Macluravirus and Yam Badnavirus which were reported in other yams from India. The leaf and tuber samples of lesser yam were indexed for YMMV, Yam Macluravirus by double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcription (RT-PCR) whereas Yam Badnavirus was by triple antibody sandwich enzyme linked immunosorbent assay (TAS-ELISA) and polymerase chain reaction (PCR). Yam Mild Mosaic Virus is the most prevalent virus detected in 74.28% of the samples followed by Yam Badnavirus (42.85%) and Yam Macluravirus (40%). Mixed infections of YMMV-Macluravirus (34.28%), YMMV-Badnavirus (31.42%), Macluravirus-Badnavirus (14.2%) and combination of these three viruses (14.2%) were also observed. Two pairs of novel species specific primers were developed to amplify the partial coat protein gene of YMMV and Yam Macluravirus. After identification, one sample each for YMMV, Yam Macluravirus and Yam Badnavirus were cloned and sequenced. The sequence data was analyzed through BLAST and111 sequence similarity was studied. YMMV has maximum similarity of 86% to Yam Mild Mosaic Virus isolate CN20, complete genome, whereas Yam Macluravirus, 95% to YMCTCRI-01 polyprotein gene and Yam Badnavirus, 99% to Dioscorea bacilliform virus 1 gene for polyprotein, isolate FJ65c De. The result obtained from this study will be useful for indexing the planting materials which helps in production of healthy planting material and germplasm there by helping the farming communities to get potential yield UR - http://krishikosh.egranth.ac.in/handle/1/5810111306 ER -