Dr. Xiaosa Jack Xu, Professor of Plant Biology at University of California Davis, will be presenting a talk about his work entitled “An Evolutionary View of Plant Inflorescence Development from Single-Cell and Spatial Profiling.”\u00a0 The abstract is as follows:<\/p>\n
Inflorescence architecture is a major determinant of reproductive success and crop yield, yet how its developmental regulation evolves across phylogenetic scales remains incompletely understood. Here, we integrate single-cell transcriptomics, spatial gene expression, and gene editing to examine inflorescence development across three hierarchical evolutionary levels: a deep comparison between monocots and eudicots, a closer comparison within cereal monocots, and a near-scale comparison between maize and its wild progenitor, teosinte.<\/p>\n
At the broadest scale, we generated a comparative single-cell atlas of developing inflorescences in Arabidopsis and maize. This analysis recovered thousands of stem cells marked by CLAVATA3<\/em> and WUSCHEL<\/em> and uncovered conserved stem cell regulators, including members of the SERPINE1 mRNA-binding protein family, revealing deeply conserved mechanisms underlying shoot meristem maintenance across monocots and eudicots.<\/p>\n At an intermediate scale, we performed an integrative analysis of single-cell transcriptomes from developing inflorescences of five cereal crops: maize, wheat, barley, rice, and sorghum. We identified shared cell populations and resolved distinct meristem subdomains, revealing a conserved core of meristematic cell identities and regulatory programs, alongside divergence in transcriptional programs associated with lateral organ initiation and differentiation that likely underlie species-specific cereal inflorescence architectures.<\/p>\n At the closest scale, we constructed a single-cell atlas of developing teosinte ears and compared it with maize to investigate domestication-associated changes in ear development. We identified cell-type-specific differentially expressed genes in inflorescence stem cells and axillary meristem-initiating cells, many showing signatures of selection during domestication. Higher-order mutants in SPL<\/em>, UB2<\/em>, UB3<\/em>, TSH4<\/em>, and GLUTAREDOXIN<\/em> genes reverted ear morphology toward teosinte-like forms.<\/p>\n The presentation will begin at 3:00 PM in Lapham Hall N101, preceded by an informal reception from 2:45 \u2013 3:00PM.<\/p>","excerpt":"","slug":"biological-sciences-colloquium-xiaosa-jack-xu","image":{"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026.jpg","id":9765,"extension":"jpg","width":1440,"height":1080,"filesize":351316,"sizes":{"medium":{"width":300,"height":225,"mime-type":"image\/jpeg","filesize":18238,"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026-300x225.jpg"},"large":{"width":1024,"height":768,"mime-type":"image\/jpeg","filesize":140258,"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026-1024x768.jpg"},"thumbnail":{"width":150,"height":150,"mime-type":"image\/jpeg","filesize":7208,"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026-150x150.jpg"},"medium_large":{"width":768,"height":576,"mime-type":"image\/jpeg","filesize":87222,"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026-768x576.jpg"},"uwm_academics_program_card":{"width":800,"height":400,"mime-type":"image\/jpeg","filesize":64525,"url":"https:\/\/uwm.edu\/biology\/wp-content\/uploads\/sites\/21\/2026\/04\/Xu-2026-800x400.jpg"}}},"all_day":false,"start_date":"2026-04-24 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