Analysis of factors influencing successful Agrobacterium-mediated genetic transformation in two different explants of peanut (Arachis hypogaea L.) variety BINA Chinabadam-2

Abstract

Peanut (Arachis hypogaea L.) is a nutritious oil-seed crop. It has low productivity due to its susceptibility towards many biotic and abiotic factors. It has incompatibility towards conventional breeding techniques, thus imposing a barrier towards its germplasm improvement. Under the situation genetic engineering in peanut offers an alternative improvement technique in order to achieve improvement in its germplasm, thereby, enhancing its productivity. This study was carried out to analyze various transformation factors to determine their optimal condition so that a proper protocol can be established to carry out transformation in two explants, namely, decapitated half embryo and whole embryo of BINA Chinabadam-2. The explants were prepared and infected in Agrobacterium culture media. The explants were then allowed to co-cultivate in MS media containing 2mg/l BAP and 1mg/l kinetin. 25% of the explants were analyzed for transient expression by GUS histochemical assay and the rest were transferred to regeneration media containing 200mg/l cefotaxime. High transformation efficiency was received with minimum of 1 hour of infection duration, 24 hours of co-cultivation and optical density (600nm) of close to 1.0 in case of decapitated half embryo explants. One day old explants gave good response. For whole embryo with cotyledon attached, pre-culture of explants had negligible effect while an optical density of 1.0 gave best result which is in accordance to the results received for decapitated half embryo.