ASHOK B SHARMAMonday , May 26, 2008

New Delhi, May 25 Tamil Nadu Agriculture University (TNAU) is developing transgenic hill banana, which would be resistant to bunchy top virus (BBTV).

Speaking to FE, P Balasubramanian of the TNAU's centre for plant molecular biology said, "We are planning to engineer resistance in the hill banana cultivar, Virupakshi against BBTV. A full-length 850bp replicase gene of BBTV from infected hill banana was isolated in our laboratory. The isolated sequence showed a high homology to the already reported BBTV replicase gene sequence from India in NCBI database. The isolated replicase gene may be cloned into RNA silencing (RNAi) vector, panda, sourced from Nara Institute of Science and Technology, Japan. The silencing gene construct developed may be used in hill banana transformation."

Balasubramanian further said that that in addition to hill banana, TNAU was working on transgenic transformation of the popular Cavendish banana cultivar, Robusta (AAA). So far an efficient regeneration protocol has been standardised on Robusta. Successful regeneration of a diploid banana, Ney poovan (AB) has also become possible. Hill bananas are perennial in nature and are found at an altitude of 2,000 to 5,000 feet above sea level in the region of well distributed annual rainfall of 1,250-1,500 mm.

Hill bananas are the ruling crop of the lower Pulneys hill ranges, Sirumalai and Kolli hills of Tamil Nadu from the 1940s. BBTV has been the sole cause for reduction in hill banana cultivation from 18,000 hectare in 1970s to a mere 2,000 hectare at present.

"None of the strategies now available are able to completely protect the plants against BBTV. Improvement of this crop through conventional breeding has not been successful," said Balasubramanian