Studies of the infectivity of cloned Rice tungro bacilliform virus isolates from eastern India.


Four different Indian isolates of RTBV (viz. Assam, Andhra Pradesh, Tamil Nadu and West Bengal) were cloned from tungro infected Rice plants. Their sequence analysis and comparison showed that the Andhra isolate has the maximum similarity while the other isolates have the similarity range of 60-90% with the Philippines isolate. More resemblance was observed in case of restriction maps among the Indian isolates (West Bengal and Assam) as compared to the Philippines isolate. A PCR-RFLP based variability study done between cloned RTBV DNA and naturally infected field rice sample revealed a mixed population of viral genomes in field samples. In addition, the study on the promoter region of the West Bengal isolate revealed a functional and efficient promoter than the control vector. The construction of a full length agroinfectious clone of the West Bengal isolate was also attempted.