Faculty Affairs and Academic Programs
Xiaosa Xu
Life Sciences; Agriculture and Veterinary Sciences
Resolving the Cellular Basis of Maize Ear Domestication to Enhance Yield Potential
Maize is a cornerstone of the global food system and the primary U.S. feedstock for starch-based bioethanol, yet increasing yield remains a challenge. Kernel row number (KRN)—kernel rows on the maize ear—is a key yield trait that increased dramatically during domestication, but its underlying genetic and developmental mechanisms remain poorly understood due to its polygenic nature and limitations of bulk-tissue analyses. This project will use cutting-edge single-cell RNA sequencing (scRNA-seq) and functional genomics to resolve, for the first time, cell-type–specific regulators controlling ear meristem activity, driving changes in KRN. >>Aim 1 will generate a high-resolution single-cell transcriptomic atlas of developing teosinte ears, identifying differentially expressed genes in inflorescence and spikelet-pair meristems overlapping with known KRN Quantitative Trait Loci (QTLs). >>Aim 2 will extend this comparative framework to high- and low-KRN lines from the Teosinte Nested Association Mapping (TeoNAM) population to integrate gene expression with allelic variation and prioritize candidate regulators. >>Aim 3 will functionally validate top candidates in maize using CRISPR-Cas9 mutagenesis and overexpression, assessing effects on meristem development and KRN. This project will clarify how domestication-driven transcriptional changes shaped yield traits. The resulting datasets, genes, and tools will be shared via MaizeGDB and public stock centers. This award will position PI Xu and the University of California as leaders in crop single-cell genomics and evolutionary developmental biology. This work will inform strategies to modify ear development and boost yield.
