Genome-wide analyses on transcription factors and their potential microRNA regulators involved in maize male fertility
Ziwen Li, Taotao Zhu, Shuangshuang Liu, Yilin Jiang, Haoyun Liu, Yuwen Zhang, Ke Xie, Jinping Li, Xueli An, Xiangyuan Wan
Abstract
Anther development is a programmed biological process crucial to plant male reproduction. Genome-wide analyses on the functions of transcriptional factor (TF) genes and their microRNA (miRNA) regulators contributing to anther development have not been comprehensively performed in maize. Here, using published RNA-Seq and small RNA-Seq (sRNA-Seq) data from maize anthers at ten developmental stages in three genic male-sterility (GMS) mutants (ocl4, mac1, and ms23) and wild type W23, as well as newly sequenced maize anther transcriptomes of ms7-6007 and lob30 GMS mutants and their WT lines, we analyzed and found 1079 stage-differentially expressed (stage-DE) TF genes that can be grouped into six (premeiotic, meiotic, postmeiotic, premeiotic-meiotic, premeiotic-postmeiotic, and meiotic-postmeiotic clusters) expression clusters. Functional enrichment combined with cytological and physiological analyses revealed specific functions of genes in each expression cluster. In addition, 118 stage-DE miRNAs and 99 miRNA-TF gene pairs were identified in maize anthers. Further analyses revealed the regulatory roles of zma-miR319 and zma-miR159 as well as ZmMs7 and ZmLOB30 on ZmGAMYB expression. Moreover, ZmGAMYB and its paralog ZmGAMYB-2 were demonstrated as novel maize GMS genes by CRISPR/Cas9 knockout analysis. These results extend our understanding on the functions of miRNA-TF gene regulatory pairs and GMS TF genes contributing to male fertility in plants.