RESEARCH-PGR: Integration of cellular recycling pathways in C4 leaves

This project will undertake a comprehensive molecular analysis to understand how different plant cells within leaves mobilize nutrients through a cellular process called autophagy (“self-eating”) and what compensatory mechanisms are activated when autophagy fails. With such knowledge, it should be possible to re-engineer crops that more efficiently use nutrients, that better remobilize these nutrients to areas of new growth and storage, and that provide better yields under normal and stressful conditions. The participating investigators will provide training to students and postdoctoral fellows in modern biological approaches to study crop physiology. At UW Madison, high school students will be trained through the “Wisconsin Youth Apprentices” program, a state-certified program designed to provide high school students with experiences in industry and academic research. At MSU, data generated in this project will be used in an undergraduate course to enhance students’ analytical skills. The four labs will design and implement both virtual and in-person workshops during scientific meetings. Autophagy is a central regulator of the cellular, developmental, and physiological responses that underlie key agricultural traits, such as fertilizer-use efficiency and remobilization, carbon allocation, seed quality and germination, yield, and tolerance to environmental stress. However, current understanding of the organization, regulation, and cell-type specificity of autophagy in crops is limited. This project has four aims: 1. Analyze how autophagy impacts cellular recycling of photosynthetic maize leaf cell types using pooled cell-type omics approaches (proteomics, transcriptomics, and metabolomics). 2. Analyze the mechanisms of chloroplast remodeling and turnover by different autophagy-related pathways at the single-chloroplast type level. 3. Identify gene regulatory networks controlling cellular recycling in maize leaf cell types by integrating omics data at the cell-type, single-cell, and chloroplast-type levels. 4. Experimentally test predicted metabolites and transcription factors as potential regulators of autophagy and nutrient mobilization in maize. Collectively, this work will provide the first analysis of cellular and nutrient recycling in different leaf cell types in a crop plant. 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.