Expanding the maize domestication gene network: from phenotype to gene

Like other crop plants, corn or maize was domesticated from a wild plant species. Corn was domesticated approximately 10,000 years ago in southern Mexico. Domestication profoundly transformed the structure and appearance of the corn plant, converting an unproductive wild species into the most highly productive crop grown in the US today. The research will elucidate the genetic basis for some of these changes in plant structure. Specifically, the research will identify two of the genes that converted pollen bearing tassels into seed bearing ears during domestication. This conversion of tassels into ears is central to the mechanism that made corn a highly productive crop grown throughout the world today. Once the two new genes are identified, the research will also dissect how these genes work in concert with other known genes to form a ?gene network? controlling the structure of the maize plant. Each gene in the network is like an individual gear in a complex machine of many gears that work together. Understanding this gene network will facilitate the efforts of plant breeders to improve maize even more. To reach beyond the maize genetics? community, this project will engage the broader society in four ways: (1) Develop public outreach and education displays on crop domestication, (2) establish an annual workshop for US and Mexican plant scientists, (3) train undergraduate students from disadvantaged backgrounds, and (4) train graduate students in effective communication of scientific research.<br/><br/><br/>This research will better define the gene network that was modified to produce domesticated maize from its wild progenitor, teosinte. Previously, several genes contributing to the transformation of teosinte into maize have been identified: teosinte branched 1 (tb1) that regulates plant and inflorescence structure; teosinte glume architecture 1 (tga1) that regulates ear structure; grassy tillers 1 (gt1) that regulated plant architecture; and enhancer of tb1 (etb1.2) that affects ear structure. These four genes are members of a maize gene network that controls plant and inflorescence architecture. The project will focus on the conversion of the staminate inflorescences (tassels) at the tips of primary branches in teosinte into the pistillate inflorescences (ears) in maize. The aims of the project are: (1) fine-map a quantitative trait locus (QTL) called stam2.1 to its underlying gene, (2) fine-map a second QTL called stam1.1 to its underlying gene, and (3) characterize the interactions of stam1.1 and stam2.1 with tb1 at the phenotypic and gene expression levels. The research will add to the understanding of domestication and the genetic control of plant development. To engage the broader community, four activities will be undertaken. (1) An annual workshop for plant scientists in the US and Mexico will be organized. (2) One undergraduate student from a disadvantaged background will be trained each year. (3) UW Graduate students will develop and present ?exploration stations? on crop domestication for public outreach. (4) A graduate level course on giving effective lectures to large audiences will be developed.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.