Meristem Power: The power of the inflorescence meristem to determine spikelet number per spike in wheat

The inflorescence meristem (IM) is the first reproductive meristem during plant development, and provides the foundation for all existing floral variation, inflorescence architecture and ultimately productivity. Previously studies in other plant models revealed that manipulating IM size can induce plants to produce more floral organs. However, how IM regulate spike development and influence yield traits in wheat is poorly studied. Recently, my host lab uncovered two dominant mutant alleles of MADS-box gene, SHORT VEGETATIVE PHASE1 (SVP1) and VEGETATUVE TO REPRODUCTIVE TRANSITION2 (VRT2), that lead to increased grain floral tissue and grain length in wheat. When combined knockout mutant alleles of these two genes, with the svp1vrt2 double mutant leading to 70% more spikelet number per spike (SNS). My preliminary data showed that TaWOX (WUS-related homeobox) expression generally decreased in VRT2-high expression dominant mutant at early spike developmental stages, indicating VRT2 involved in IM maintenance by fine tuning TaWOX genes. Combining these preliminary results led me hypothesize that increasing IM activity in wheat will lead to an increase in SNS, and potentially yield. In this proposal, I will use svp1 vrt2 mutants and TaWOX2 transgenic lines and combining the recent breakthroughs in wheat genomics and gene editing approaches to pursue my three main objectives:

1. Determine whether increased SNS in svp1 vrt2 mutants is caused by enlarged IM size
2. Elucidate the role of TaWOX2 on establishing and maintaining IM activity in wheat
3. Uncover novel genes controlling IM size and spike development in wheat

Through this fellowship, I will greatly broaden the knowledge of the wheat IM development and its correlation with yield, gain advanced training and practical experience in technical and transferable skills, expand my collaborative network, and enhance my professional maturity to achieve my competences and ambition to be an independent research group leader.