MAIZE EAR DEVELOPMENT, A NEW PATHWAY ACTING THROUGH FASCIATED EAR3

This project will characterize a new developmental signaling pathway in maize that has the potential to improve grain yields. We previously identified a mutant of maize called fasciated ear3 (fea3), in which tassel and ear development is severely affected; both are enlarged, particularly at the growing tip, or stem cell-containing meristem. The FEA3 gene encodes a trans-membrane receptor protein, similar to CLAVATA type receptors that function in stem cell signaling and maintenance in other plants, and we found that it functions in a pathway that is distinct from the canonical CLAVATA pathway. In recent studies, we have started to build a molecular pathway around FEA3, by identifying interacting proteins, including a second receptor protein, maize BARELY ANY MERISTEM1d (ZmBAM1d), and a candidate downstream signaling protein, protein phosphatase 2A (PP2A). Interestingly, our collaborative studies have associated the ZmBAM1d gene with control of seed size in maize, providing potential new insights into the tradeoff between seed number and seed size in detTo perform a detailed analysis of fea3 mutants, and mutants in its candidate co-receptor, ZmBAM1d, to understand their dual role in ear meristem and seed development.To ask if the ZmBAM1d receptor can bind FCP1, a candidate ligand in the FEA3 pathway, and find other proteins that interact with the FEA3 receptor, using a new proximity labeling proteomics approach.To ask if FEA3 and ZmBAM1d can improve maize yields, through their effect on kernel row number and kernel size.