MdMYB88/124 modulates apple tree microRNA biogenesis through post-transcription processing and/or transcription pathway
Chun-dong Niu, Huan-ran Shi, Zi-tong Zhang, Tian-le Fan, Huan Dang, Peng-xiang Chen, Yin-peng Xie, Cha-na Bao, Feng-wang Ma, Qing-mei Guan and Xue-wei Li
Acta Physiologiae Plantarum
https://doi.org/10.1007/s11738-022-03424-4
Abstract
MicroRNAs are a class of endogenous small-RNA, which repress gene expression through post-transcriptional regulation. MdMYB88/124 (MYELOBLASTOSIS88/124), an R2R3-MYB transcription factor, regulates plants tolerance towards abiotic stress. In this study, we show that MdMYB88/124 alters the expression levels of some miRNAs, including mdm-miR156a-P5, mdm-miR164c-P5, mdm-miR166c-P5, mdm-miR391-P5, mdm-miR399-P3, mdm-miR399b-P5, mdm-miR2111a-P3, and mdm-miR7121a-P5. Furthermore, from the 18 analyzed pri-miRNAs, all of them showed increased expression in MdMYB88/124 RNAi plants. Y2H, BIFC, Split Luc, and Co-IP assays showed that MdMYB88/124 interacted with MdHYL1 (HYPONASTIC LEAVES1), a key factor in pri-miRNA and pre-miRNA splicing in vivo and in vitro. And we also found MdMYB88 could regulate the expression of MIR genes through the transcription pathway by dual-luciferase assay. In conclusion, we hypothesize that MdMYB88/124 can not only regulate MIRs expression by binding to their promoters, but also act as a co-factor with MdHYL1 to participate in miRNA biogenesis processing.