Genome-wide analysis of the R2R3-MYB gene family revealed LbaMYB2 as a candidate regulator associated with male sterility in Lycium barbarum

The R2R3-MYB family is one of the largest transcription factor families in plants, and several members have been established as critical regulators of pollen development and fertility; however, their roles in Lycium barbarum L. (wolfberry) remain largely unexplored. In this study, we performed a genome-wide identification of R2R3-MYB family members in L. barbarum and screened for candidate genes associated with pollen fertility regulation. By combining HMM profiling with BLASTP searches, we identified 133 R2R3-MYB genes in the L. barbarum genome, designated LbaMYB1 – LbaMYB133 according to their chromosomal positions. Among them, LbaMYB2 , encoding the closest homolog of Arabidopsis AtMYB80/MS188 , a well-characterized regulator of tapetum development, callose dissolution, and pollen exine formation, exhibited peak transcript accumulation at the pollen mother cell (Pm) stage and was significantly upregulated in the male-sterile line Ningqi No. 5 compared with the fertile line Ningqi No. 1. Consistent with previous cytological characterization of this sterile line, paraffin sectioning revealed delayed tapetal programmed cell death (PCD) and a persistent tapetum in Ningqi No. 5, accompanied by microspore abortion from the late tetrad to the pollen grain stage. Subcellular localization assays confirmed that the LbaMYB2 protein is localized to the nucleus. Taken together, our results identify LbaMYB2 as a candidate regulator of pollen fertility in L. barbarum , providing a foundation for subsequent functional characterization and mechanistic studies.