Identification and Characterization of a Homologue to the Arabidopsis INDEHISCENT Gene in Common Bean

Reduction in pod shattering represents a key component of the domestication syndrome in common bean (Phaseolus vulgaris) and makes this domesticate dependent upon the farmer for seed dispersal. Attempts to elucidate the genetic control of this process have led to the identification of a major gene (St) linked to the presence/absence of pod suture fibers affecting pod shattering. Although St has been placed on the common bean genetic map, the sequence and the specific functions of this gene remain unknown. The purpose of this study was to identify a candidate gene for St. In Arabidopsis thaliana, INDEHISCENT gene (IND) is the primary factory required for silique shattering. A sequence homologous to IND was successfully amplified in P. vulgaris and placed on the common bean map using two recombinant inbred populations (BAT93 × Jalo EEP558; Midas × G12873). Although PvIND maps near the St locus, the lack of complete cosegregation between PvIND and St and the lack of polymorphisms at the PvIND locus correlated with the dehiscent/indehiscent phenotype suggests that PvIND may not be directly involved in pod shattering and may not be the gene underlying the St locus. However, PvIND may be closely linked to an as yet unidentified regulatory element at the St locus. Alternatively, a more precise phenotyping method taking into account quantitative trait variation needs to be developed to more accurately map the St locus.