Identification and Clarification of VrCYCA1: A Key Genic Male Sterility-Related Gene in Mungbean by Multi-Omics Analysis

Abstract

Heterosis has been utilized in crops for a long time, and although crop fertility is the basis for the utilization of heterosis, there is limited information concerning the genic male sterility (GMS) of mungbean. Therefore, based on the genic male sterile mutant, M1, obtained by EMS mutagenesis of the Weilyu cultivar, this project used multi-omics analysis to detect the male sterile site and further identify its candidate gene, and then the mechanism of the candidate gene was discussed. As a result, one locus region (Chr5: 6,835,001–6,935,000 bp) associated with GMS was identified, and nine genes were found within the 100 Kb region. The candidate gene, VrCYCA1, around the above loci had a TATA box deletion approximately 4.7 Kb upstream of the gene, and this was evidenced by comparative genomics, transcriptome analysis, and RT-qPCR analysis. The expression level of VrCYCA1 was significantly downregulated (log2FC = −2.06, p-value = 0.025) in the ms lines compared with the control group. Moreover, 6653 genes showed differential expression between the Weilyu lines and mutant lines as well as 165 metabolites with significant differences in their concentration levels. Among those differentially expresses genes, 226 were annotated with functional categories involved in flowering and endosperm development, and six genes had protein–protein interactions with VrCYCA1. Seven categories of metabolites and seven genes participated in the relationship between reproductive growth and vegetative growth, which might have caused the sterility of mungbean in the mutant plants. This study used multi-omics data to mine a mungbean GMS-related gene, VrCYCA1, and constructed a GMS genetic network to explore the molecular mechanism of VrCYCA1. The results lay a solid foundation for further molecular biology research and utilization in mungbean male sterility.