VrMYB80 Shapes Pollen Development in Mungbean by Activating VrLBD27 and VrWBC27

Researchers studying mungbean (Vigna radiata) have mapped, for the first time, the genome-wide set of genes controlled by VrMYB80, an R2R3-MYB transcription factor previously identified as a key regulator of male fertility in this crop. The work combined DNA affinity purification sequencing (DAP-seq) with transcriptome profiling to identify the direct transcriptional targets of the protein.

The DAP-seq analysis showed that VrMYB80 binds preferentially to promoter regions across the mungbean genome. By integrating these binding data with RNA-seq expression profiles, the team identified 292 differentially expressed genes that carry VrMYB80-binding peaks in their promoter regions, marking them as candidate direct targets.

Enrichment analyses using KEGG and GO frameworks indicated that the downregulated target genes were mainly associated with several functional categories, including energy supply, regulation of enzyme activity, protein processing, and metabolic pathways. This pattern suggests that VrMYB80’s influence on pollen development extends across multiple cellular processes rather than a single pathway.

Among the significantly downregulated target genes, two stood out: VrWBC27 and VrLBD27. These genes are homologs of the Arabidopsis thaliana genes WBC27 and LBD27, respectively, and the authors propose they may be involved in the regulation of pollen development in mungbean.

To test whether VrMYB80 directly controls these two genes, the researchers performed dual-luciferase reporter assays. The results showed that VrMYB80 activates the promoters of both VrWBC27 and VrLBD27, consistent with a direct activating role rather than repression.

Spatial evidence added further support. In situ hybridization revealed that both VrWBC27 and VrLBD27 are expressed in the tapetum, the nutritive tissue essential for pollen development, and that this expression pattern overlaps spatially with that of VrMYB80 itself.

Collectively, these findings suggest that VrWBC27 and VrLBD27 are likely direct targets of VrMYB80, forming a regulatory link between this transcription factor and the cellular machinery of pollen formation in mungbean.

The study represents the first genome-wide identification of VrMYB80 targets in mungbean using DAP-seq, and the authors state that it provides novel insights into the molecular mechanisms governing pollen development in this legume crop. As the work is published as an early, peer-reviewed accepted version of record, further edits may follow in the final version.

Subject of Research: Genome-wide identification of VrMYB80 transcriptional targets regulating pollen development in mungbean

Article Title: Downstream target screening reveals that VrMYB80 regulates pollen development in mungbean (Vigna radiata L.) by modulating VrLBD27 and VrWBC27 expression

Article References: Wang, Q., Chen, J., Zhu, S., Yuan, X., Lin, Y., Wu, R., Liu, J., Yuan, N., Zhang, X., Pu, Y., Wu, Y., & Chen, X. (2026). Downstream target screening reveals that VrMYB80 regulates pollen development in mungbean (Vigna radiata L.) by modulating VrLBD27 and VrWBC27 expression. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09780-4

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09780-4

Keywords: mungbean, VrMYB80, pollen development, DAP-seq, transcription factors, VrLBD27, VrWBC27, tapetum, male fertility, gene regulation, Vigna radiata, Downstream