Fine Mapping and Screening of Candidate Gene for Yellow-to-Green Mutation in Snap Bean (Phaseolus vulgaris L.) Leaf Color

The yellow-to-green mutation in plant leaf color can be easily identified and used as a marker trait for seed purity identification, improved variety breeding, hybrid purity identification, and hybrid production. In this study, the leaves of yellow-to-green mutant ytg-1 of snap bean were selected as the experimental material, and the physiological mechanism underlying the leaf color change was studied. The mechanism was observed to belong to the lack of recovery type in the total chlorophyll stage. The decrease in chlorophyll content was due to the inhibition of the synthesis of Proto IX to Mg Proto IX. Genetic analysis revealed that a single recessive gene, pvytg-1, controlled the mutation trait. The gene was located in the 80-kb region of chromosome 10. Overall, six genes were observed within this interval, and based on gene functional annotation, Phvul.010G041700 was identified as the candidate gene. Sequencing and identification of Phvul.010G041700 revealed a single base insertion in ytg-1 compared with the wild-type, resulting in premature termination of the gene. The results of this study will facilitate the breeding and genetic improvement of snap bean in the future.