CAREER: Mechanisms of division plane orientation in plant cells

University Of California-Riverside, Riverside CA

Investigators

Abstract

This research seeks to understand the mechanisms regulating proliferative plant cell division, which eventually generates the majority of biomass on the planet. Precise control over the positioning of divisions within cells plays a critical role in overall patterning and development. Despite its fundamental importance, we know relatively little about how division planes are oriented in multicellular organisms. Plants are an excellent model to understand division plane orientation within multicellular contexts because plant cells do not migrate and have clearly defined structures and proteins that unambiguously label the future division site. This project will investigate 1) how division site-localized proteins and microtubules promote proper positioning of the new cell wall 2) how the cell division machinery is guided towards the division site, and 3) how the position of the cell division plane is modulated by local mechanical or biochemical cues from neighboring cells. This project will provide training that advances the U.S. scientific workforce in plant biology, an area of national need. One graduate student, two undergraduates, five REU students, and one postdoctoral researcher will perform this research while gaining experience in communicating their work at local and national conferences, mentoring others, project management, and ethics. In addition, 480 freshman biology students will participate in this research to enhance their technical training and understanding of genomics and molecular biology approaches. The investigator continue to train and mentor under-represented, first-generation undergraduate and graduate students from UCR, a Hispanic Serving Institution. To test the hypothesis that division site localized proteins modulate microtubule dynamics to position the forming cell wall, the investigator will use a combination of in vitro microtubule protein-interaction assays combined with in vivo imaging at the division site. In addition to assessing how currently known proteins function at the division site, the investigator has used a forward genetic approach to identify mutants with defects in cytokinesis and division plane orientation in maize. Using mapping-by-sequencing, she will identify the causative mutations in these mutants, and elucidate their interaction with known division plane orientation pathways and proteins. She hypothesizes that two functionally redundant pathways contribute to division plane positioning in Arabidopsis. She will use a sensitized mutant background to screen for synthetic enhancer mutations that cause defects in division plane orientation. This will be carried out by an introductory biology laboratory course at University of California, Riverside (UCR). Finally, she will use a combination of mathematical modeling and biophysical experiments to identify local cues that alter plant division plane positioning. 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.