绿豆柱头外露突变体se2的特征特性分析及候选基因挖掘OA

Stigma-exsertion materials can facilitate cross-pollination in mungbean under natural conditions,improve the effi-ciency of hybrid seed production,and promote the breeding of new mungbean varieties with stigma exsertion.In addition,identi-fying genes that regulate stigma development will contribute to the utilization of heterosis in mungbean.In this study,the mung-bean cultivar Jilyu 7(WT)was used as the experimental material,and a genetically stable stigma-exsertion mutant,se2,was iden-tified through ethyl methanesulfonate(EMS)mutagenesis and artificial screening.Phenotypic characterization,genetic analysis,and candidate gene mining were subsequently conducted.The results showed that,compared with WT,se2 exhibited a signifi-cantly shortened keel flap,an exserted stigma,and normal pollen viability.In field experiments,the pod number per plant,seed number per pod,pod length,and yield per plant of se2 decreased by 83.4%,60.9%,25.1%,and 85.4%,respectively,compared with WT.In pot experiments,the number of flowers per plant,pod number per plant,and proportion of shrunken pods in se2 in-creased by 285.2%,285.9%,and 67.6%,respectively,whereas the number of mature pods per plant decreased by 93.6%,indica-ting a significant reduction in seed-setting rate.Segregation ratio statistical analysis of traits in the F2 population showed that the stigma-exsertion trait was controlled by a single recessive gene.The potential of se2 for mungbean hybrid breeding was further confirmed by bee-assisted pollination.After resequencing the mutant DNA bulk and the wild-type parent,six candidate genes related to stigma exsertion were identified through MutMap analysis,homologous sequence alignment,and expression analysis.This study lays a foundation for elucidating the molecular mechanism underlying stigma-exsertion development and for exploi-ting heterosis in mungbean.