|De Barros, Everaldo|
|Miklas, Phillip - Phil|
|Porch, Timothy - Tim|
Submitted to: Genomics of Tropical Crop Plants
Publication Type: Book / Chapter
Publication Acceptance Date: 12/11/2006
Publication Date: 1/3/2008
Citation: Gepts, P., Aragao, F.L., De Barros, E., Blair, M.W., Brondani, R., Broughton, W., Galasso, I., Hernandez, G., Kami, J., Lariguet, P., Mcclean, P., Melotto, M., Miklas, P.N., Pauls, P., Pedrosa-Harand, A., Porch, T.G., Sanchez, F., Sparvoli, F., Yu, K. 2008. Genomics of Phaseolus Beans, a Major Source of Dietary Protein and Micronutrients in the Tropics. In: Moore, P.H. and Ming, R. Genomics of Tropical Crop Plants. New York. Springer Press. Vol(1). p. 113-143. Interpretive Summary: A powerful genetic technique, TILLING (Targeted Induced Local Lesions IN Genomes), is being developed for the study of the genetics of important traits, such as yield and nutritional traits, in common bean. The TILLING technique is based on the creation of a large population of mutants that are derived from a single variety. Mutants are generated through treating the seed of the selected variety, BAT 93, with the chemical mutagen EMS. Optimal concentrations of the EMS mutagen were determined and a subset of the mutagenesis population was tested for the presence of mutations. The mutagenesis population was found to be functional through testing for a specific root mutation. The goal is to create 5,000 mutants of BAT 93, while 1,500 mutants have currently been developed.
Technical Abstract: TILLING (Targeted Induced Local Lesions IN Genomes) is a powerful reverse genetic approach that uses gene specific primers for the identification of mutants of a gene of interest from a large mutagenesis population. Theoretically, given a sufficient population size, genome saturation can be achieved and mutants for any gene can be identified. TILLING does not rely on transformation and thus allows for reverse genetic approaches in transformation recalcitrant species, such as common bean (Phaseolus vulgaris L.). Significant advances have been made in the development of a TILLING platform in common bean genotype BAT 93 through the work of the TILLING consortium. Based on genome saturation in other species, it was estimated that about 5,000 mutagenesis lines would be required for genome saturation in common bean. It was also determined that 35-40mM EMS was an optimum concentration for mutagenesis. Mutation efficacy was confirmed using a screen for nodulation mutants and found that 35mM EMS resulted in 10% putative nodulation-deficient mutants in a population of 348 M2 lines. Currently, 1,500 M2 families have been produced, and 900 families have been advanced to the M3 generation.