Candidate gene identification for angular leaf spot in common bean (Phaseolus vulgaris L.)

Abstract

Common bean (Phaseolus vulgaris L.) is a legume of great importance in human nutrition. Common bean breeding search tools that improve transfer of resistance genes to developing cultivars. Genomic tools permit to label, introgress and clone genes or QTLs through molecular markers. Resistance gene mapping enable gene, epistatic and environmental interactions studies among these QTLs, providing important information to breeding programs. The angular leaf spot, caused by the fungus Pseudocercospora griseola (Sacc.) Crous & U. Braun, causes large losses to common bean producers. Thus, genetically resistant cultivars are desirable. Fine mapping allows identification of specific allele molecular markers that co-segregate with resistance loci, making positional cloning possible. Therefore, breeder can manipulate the genetic variation, introgressing and pyramiding resistance genes through marker assisted selection or by transgenic procedures. Taking into account the continuing of the FAPESP process n° 05/53819-0 (Mapping of anthracnose and angular leaf spot resistance loci in common bean using microsatellite markers) and the FAPESP scholarship process n° 06/58332-5 ["Construction of a molecular-genetic map and mapping loci associated with angular leaf spot resistance in common bean (Phaseolus vulgaris L.) using microsatellite markers"], this project aims mapping angular leaf spot resistance and identify epistatic effects and environment interactions [linked to FAPESP process no 09/02411-2 Doctor's degree scholarship,-"Fine Mapping of loci associated to angular leaf spot resistance in common bean (Phaseolus vulgaris L)"]. The magnitude of the loci identified will be quantified. The region of the major effect locus will be studied in greater detail through its saturation with molecular markers. These markers will be used to identify candidate genes for positional cloning. (AU)