Genomic Analysis of Leaf Cuticle Development and Functional Diversity in Maize

University Of California-San Diego, La Jolla CA

Investigators

Abstract

CoPIs Michael Gore (Cornell University); Michael Scanlon (Cornell University); and Isabel Molina (Algoma University) Key Collaborators Alisa Huffaker (UCSD) and Andrew French (USDA/ARS Arid Land Agricultural Research Center) Protecting crop plants from diseases and adverse growing conditions is key to achieving sustainable food production. The cuticle is a waxy, water-proof layer on the outer surfaces of plant leaves and stems that plays a vital role in preventing water loss. It is also where plants first interact with most insects and diseases. Therefore, the cuticle is important to keep plants healthy while preventing them from drying out in the breeze. While many prior projects have contributed insights into cuticle composition, development and function, very few have focused on the adult leaves of cereal crops, whose cuticle has a significant impact on the agricultural performance of these key crops. This project will discover genes that control cuticle development and function in corn, evaluate the potential for improvement of the leaf cuticle to help produce crops with increased drought tolerance and resistance to diseases, and generate tools to guide these efforts. Prior studies have laid a foundation for understanding cuticle biogenesis and function in plants, but very few have focused on adult leaves of economically important cereal crops such as maize, and none have yet been translated to crop improvements. This project will analyze the biogenesis of adult maize leaf cuticle and its genetic basis, and will elucidate the impact of genetically determined cuticle variation on drought tolerance and pathogen penetration. The first aim is to relate genome-wide analysis of epidermal gene expression to changes in cuticle structure, composition, and function across a developmental timecourse. The second aim is to identify loci controlling cuticular evaporation (CE) rate in adult leaves via a genome-wide association study (GWAS). The third aim is to analyze maize lines selected for diversity in cuticle function to elucidate relationships between cuticle characteristics (histology, ultrastructure and composition), cuticle function as a barrier against water loss and pathogen penetration, and drought tolerance. The fourth aim is to elucidate, via network analysis, the relationships between gene expression, cuticle composition, and cuticle function. This final aim is expected to identify key genetic regulators and a systems-level understanding of the genetic basis for cuticle biogenesis and function in adult maize leaves. Project outcomes will include new insights regarding adult maize leaf cuticle development and its genetic regulation, new knowledge of the impact of cuticle modification on drought tolerance and pathogen infection in maize, and genetic tools to guide such modifications. Project outcomes and data will be communicated through multiple open access publications, a project website housed at http://labs.biology.ucsd.edu/smith/, and deposition of data to three long-term repositories: the NCBI Short Read Archive (http://www.ncbi.nlm.nih.gov/sra), Maize GDB (http://www.maizegdb.org/), and an interactive database to be hosted by the UCSD library (http://library.ucsd.edu/dc). Participation in this project will provide interdisciplinary training opportunities preparing young scientists at various stages of their education to enter the science workforce of the future. It will also broaden participation in science by involving approximately 120 undergraduates at all institutions combined, with a focus on students with minimal prior access to research opportunities and/or awareness of science career opportunities.