Collaborative Research: RESEARCH-PGR: Uncovering latent vascular function in maize

Oregon State University, Corvallis OR

Investigators

Abstract

Because of its utility as a source of food, animal feed, fuel, and other bioproducts, maize (Zea mays subsp. mays) production is valued at over $83 billion annually in the US. The increased frequency of extreme weather events like drought and flooding threaten American businesses and communities that depend on maize production. Researchers from Oregon State University (PI Leiboff) and the University of California, Berkeley (Co-PI Chuck) are working together to understand the mechanisms that regulate the maize vascular system to prepare our nation’s most important crop for climate change. In a recent breakthrough, Co-PI Chuck showed that amongst the complex network of seemingly identical veins within a maize plant, there are specialized veins with unique functions in surviving drought and accommodating plant microbes. By applying cutting edge techniques in single cell genomics, mutant mapping, and machine learning, PI Leiboff and Co-PI Chuck will uncover the secret genetics that define these specialized veins and provide tools for the rapid improvement of the maize vascular system by precision breeding. The PIs will use techniques developed by this research to provide rural and urban high school teachers with low-cost smartphone microscope kits that will improve high school student engagement with the life sciences. Data from this research will be used to produce a free educational resource, “Teaching with Single Cell Genomics” providing university educators with lesson plans, animations, multimedia presentations, and a supplemental textbook to ensure that our next generation of undergraduates in biology receive training in this revolutionary new technology. The dynamic production of the dense network of veins is critical for efficient photosynthesis in C4 grasses. Grasses produce this network through reiterative developmental programs that maintain physiological functions as tissues grow or encounter new environments. Although the products of these programs are similar in structure, these repeated events provide a unique opportunity for specialization amongst tissues generated at different times and locations. This research explores the biological question of how similar tissues within an organism can be constructed for different purposes. Maize is an ideal experimental system for studying dynamic vascular events because of its high vein density and predictable developmental sequence of initiating leaf vein subtypes. The PIs will test the hypothesis that spatiotemporal gene regulation leads to unique development and physiology amongst veins in the same plant. This research will leverage state-of-the-art advances in single cell transcriptomics to track and identify key fate-determining factors in developing leaf vein subtypes amongst all developing leaf cells. Next, researchers will collaboratively apply genomics to accelerate the mapping and functional characterization of maize specialized vascular mutants. By constructing a neural network machine learning model, this work will predict vascular phenotypes from tens of thousands of cleared leaf images to perform a GWAS of a 942-inbred mapping panel, dissecting the genetic architecture of specialized vascular development and spatiotemporal gene expression changes between alleles. Data derived from these aims will inform the precision breeding of specialized vascular traits for the continued improvement of maize to meet global demand for food, feed, and fuel. 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.