International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Andhra Pradesh.
Abstracts of the papers presented at the 16th Annual Convention and International Symposium of Indian Virological Society on “Management of Vector-Borne Viruses” at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Hyderabad, India, February 7–10, 2006.
Peanut or groundnut (Arachis hypogaea L.) is an economically important oil and protein rich crop whose seeds contain about 48% oil and 25% protein that has significant impact in the semi-arid tropics (SAT). Several biotic and abiotic constraints affect the productivity of this crop that results in great economical losses annually. The India peanut clump virus (IPCV) is soil-borne and seed-borne and transmitted by the fungus Polymyxa graminis is very significant due to the non-availability of resistance sources in the available germplasm. We have developed efficient protocols for Agrobacterium tumefaciens-mediated genetic transformation of peanut by using cotyledon explants from mature seeds that can provide large numbers of independently transformed lines. Over 50 transgenic lines of peanut were developed by using either the coat protein (cp) or replicase (rep) genes of IPCV, and characterized for gene integration and expression. Replicated field evaluations against IPCV were carried out under controlled conditions during the rainy seasons of 2002 to 2005 by using 20 transgenic lines carrying single gene inserts (10 with IPCVcp and 10 with IPCVrep) in a sick plot. The preliminary results of this trial have provided very encouraging results where six lines (4 with IPCVcp and 2 with IPCVrep) showed complete resistance to IPCV. The resistant plants did not show any stunting or expression of any morphological symptoms on the leaves. The virus titer declined with maturity in the resistant plants. In the first ELISA test conducted three weeks after sowing, all the tested plants showed the presence of IPCV while the subsequent three tests at 15 day intervals did not reveal any virus in these six lines, thus suggesting the potential of capsid and replicase genes in the induction of resistance to IPCV. Detailed results on the controlled field evaluation for virus resistance in peanut and future strategies for their deployment in the developing countries of the semi-arid tropics are discussed.
