Molecular regulation of required for maize male fertility and development of a dominant male-sterility system in multiple species.

Understanding the molecular basis of male sterility and developing practical male-sterility systems are essential for heterosis utilization and commercial hybrid seed production in crops. Here, we report molecular regulation by genic male-sterility gene () and its application for developing a dominant male-sterility system in multiple species. is specifically expressed in maize anthers, encodes a plant homeodomain (PHD) finger protein that functions as a transcriptional activator, and plays a key role in tapetal development and pollen exine formation. ZmMs7 can interact with maize nuclear factor Y (NF-Y) subunits to form ZmMs7-NF-YA6-YB2-YC9/12/15 protein complexes that activate target genes by directly binding to CCAAT box in their promoter regions. Premature expression of in maize by an anther-specific promoter results in dominant and complete male sterility but normal vegetative growth and female fertility. Early expression of downstream genes induced by prematurely expressed ZmMs7 leads to abnormal tapetal development and pollen exine formation in maize lines. The transgenic rice and plants display similar dominant male sterility. Meanwhile, the gene coupled with facilitates the sorting of dominant sterility seeds based on fluorescent selection. In addition, both the recessive male-sterility line and dominant male-sterility line are highly stable under different genetic germplasms and thus applicable for hybrid maize breeding. Together, our work provides insight into the mechanisms of anther and pollen development and a promising technology for hybrid seed production in crops.