DIFFERENTIATION OF NATURAL VARIANTS OF MUNGBEAN YELLOW MOSAIC GEMINIVIRUS BY HOST REACTIONS AND DNA-DNA HYBRIDIZATION

摘要

Eight isolates of mungbean yellow mosaic virus (MYMV) isolated from different hosts (Vigna mungo, Vigna radiata, Cdjanus cajan, Macrotyloma uniflorum and Vigna aconitifolid) and geographical regions (Bangalore, Delhi, Hisar, Ludhiana and Shekhawati) of India were transmitted by whitefly (Bemisia tabaci) to various leguminous hosts for comparative host range and symptom expression under identical conditions. They have been further compared for their genomicrelatedness with the full length and restriction fragment probes to DNA-A and DNA-B of MYMV-Bg3 (Blackgram isolate) by the dot blot hybridization method. Probes to DNA-A and - B of MYMV-Bg3 could differentiate the natural variants of MYMV occurring in Bangalore, Hisar and Ludhiana from those occurring in Delhi. Restriction fragment probes from the DNA-B showed a greater variations between the isolates. Maximum heterogenity of the two mungbean isolates from Hisar and Ludhiana and a horsegram isolate from Bangalore was found in the 0.6 kb Sail - BamHI and 1.3 kb Bamlft-HindIII genomic regions of MYMV-Bg3 DNA-B. Differences'in DNA-A of Hisar and Ludhiana isolates with the Delhi isolates were also observed.