Phenomics of stomata and water use efficiency in C4 crops

Andrew D.B. Leakey, James Fischer
Department of Plant Biology / Institute for Genomic Biology - 1206 W Gregory Dr. Urbana, IL 61801

Water use efficiency (WUE), which is physiologically distinct from drought tolerance, is a key target for improving crop productivity, resilience and sustainability. This is because water availability is the primary limitation to crop yield globally and irrigation uses the largest fraction of our limited freshwater supply. The exchange of water and CO2 between a leaf and the atmosphere is regulated by the aperture and pattern of stomata. Our mechanistic modeling indicates that stomatal conductance could be reduced or stomatal movements accelerated to improve water use efficiency in important C4 crops such maize, sorghum and sugarcane. We have developed proof-of-concept for this approach in sorghum and sugarcane, but also identified pleiotropic effects and physiological feedbacks that need to be addressed to optimize plant physiological and agronomic performance. We have made progress in addressing this issue through the use of tissue-specific promoters. We will also present new advances in the development and application of AI-enabled methods for high-throughput and deep phenotyping of stomatal anatomy and function. This includes integration of a leaf gas exchange system with a confocal microscope to gather images of stomatal aperture and pore anatomy simultaneous to measuring leaf gas exchange under controlled environmental conditions.