Regeneration and Transformation of Common Bean (\u3ci\u3ePhaseolus vulgaris\u3c/i\u3e L.)

Common bean is the most important grain legume for direct human consumption and serves as main source of dietary protein for millions of people in developing world. Genetic transformation methods can serve as an important tool to complement traditional plant breeding methods for common bean improvement. Low transformation frequencies and unstable genetic integration associated with biolistic methods limits its use for routine transformation of common bean. In an attempt to develop Agrobacterium tumefaciens mediated transformation protocol for common bean, potential of primary leaves as an explant was analyzed following unsuccessful results with other tissues. Primary leaf explants were prepared from 5 days old seedlings of common bean great northern cultivar Coyne and inoculated with Agrobacterium tumefaciens strain EHA 101. Explants were cultured on MSB5 media with two different concentrations of growth hormones. Primary leaf explants show significant differences in growth on these two different media after 2 weeks and 4 weeks of culture. Transgenic callus and fully transformed roots were recovered for the first time using primary leaf explants. In attempt to regenerate primary leaf explants different factors were analyzed. Four different predefined major and minor salt compositions were tested for their suitability for leaf explant regeneration. Leaf explants exhibit significant differences in growth on four different media, indicating possible role of total nitrogen and NH4+:NO3- ratio on the growth of leaf explants. This work suggests that leaf explants can be pursued for common bean transformation. Co-Advisors: Amitava Mitra and Thomas E. Clement