Loss or reduction of natural seed dispersal was selected from a dehiscent wild common bean (Phaseolus vulgaris L.) ancestor during domestication. Pods of wild beans have also fibers in their sutures (string) and the pod walls. Complete loss of these fibers leads to indehiscence and lack of string of the pods in many modern bean varieties. Although the identification of the genes controlling dehiscence and absence of pod string will be useful for plant breeding, little is known about the molecular genetic basis of both mechanisms in common bean. In this study, we employed multiple experimental approaches to explore the genetic mechanism underlying the evolution of indeshicent and stringless phenotypes in domesticated common beans. Comparative genomics and genome database of soybean and its legume model plants Medicago truncatula, Lotus Japonicus, Glycine max and Pisum sativum were used to identify candidate genes in common bean related to known endocarp determinant genes. A recombinant inbred (RI) mapping population was evaluated for measurements of whole pod morphology, especially those affecting hardness of cell walls, string (on a 0–9 scale) and dehiscence vs. indehiscence. The RI population was genotyped using polymorphisms (Derived Cleaved Amplified Polymorphic Sequences (dCAPS) and Simple Sequences Repeat (SSR)) found in the homologous genes of fruit dehiscence-related genes identified (AGAMOUS, FRUITFULL, SHATTERPROOF, INDEHISCENT, ALCATRAZ, SECONDARY WALL THICENING PROMOTING FACTOR, POLYGALACTURONASE), and that were added to the linkage map to identify quantitative trait loci (QTL) for pod traits. Significant markers identified in this study provide a cost-effective and an efficient method for introgression and pyramiding of favorable alleles for pod dehiscence and lack of string via marker-assisted selection in common bean improvement programs.

This work was financially supported by the MINECO 2014-2017. AGL2014-51809-R

Trabajo presentado en Barcelona entre el 26 y el 29 de Junio de 2017.

Peer reviewed