TY - BOOK AU - Manasa V G AU - M L Jeeva(Guide) TI - Detection and characterization of Macluravirus infecting greater yam (Dioscorea alata L) U1 - 660.6 PY - 2014/// CY - Vellayani PB - Department of Plant Biotechnology, College of Agriculture KW - Plant Biotechnology N1 - MSc(INT) N2 - Yams constitute a group of Dioscorea species cultivated mainly in Asia, Africa and South America for their edible, underground tubers. Viral pathogens are one of the most important factors threatening production of this vegetatively propagated crop. Yam viruses are poorly characterized, which is a hindrance to the safe movement of germplasm. The overall aim of this study was to detect Macluravirus infecting greater yam and to characterize the virus at molecular level. Serological and nucleic acid based methods were employed for the detection of Macluravirus infecting greater yam, which was not previously detected in India. Analysis of greater yam leaf and tuber samples by double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA), dot immunobinding assay (DIBA) and reverse transcription polymerase chain reaction (RT-PCR) followed by sequence analysis revealed the occurrence of Macluravirus. Novel species specific primers were developed to amplify the full coat protein gene of the virus. Sequence and phylogenetic analyses, based on the entire CP- coding region revealed considerable variability and the virus was found to be more similar to Chinese yam necrotic mosaic virus (ChYNMV) than other viruses of the genus Macluravirus. The virus coat protein gene exhibited only 65 to 70% nucleotide sequence identity with other macluraviruses indicating that it is putative new species. Hence the name Yam macluravirus is proposed for the new sequence reported. Restriction digestion with Mse1 enzyme followed by DNA polyacrylamide gel electrophoresis (DNA PAGE) showed presence of intraspecific variation within the virus isolates obtained from CTCRI field. Mechanical inoculation and insect transmission of the virus on Nicotiana benthamiana, N. tabaccum and Vigna unguiculata plants yielded negative results. These results will be useful for reliable virus indexing to facilitate the safe movement of greater yam planting material and exchange of germplasm within and outside India UR - http://krishikosh.egranth.ac.in/handle/1/5810109490 ER -