Since their emergence over 400 million years ago, vascular land plants (tracheophytes) have acquired traits that enable fitness in unstable environments. Subsequent domestication of wild species into crops and more recent selection for yield under managed cultivation has resulted in loss of genetic variation that provides climate resilience. Survival of floods and droughts is determined by plasticity in physiology and development. We have studied variation in opposing resilience strategies associated with flooding survival in rice and other crops. Given current and projected climate challenges, we have turned our focus to mechanisms that provide the flexibility for pre-flowering plants to transition from water-saturated to dry soils. Our focus is on roots, the first responders to water stress (flooding and drought) and desubmergence and drought recovery, which are also stresses. Key are plastic traits influence root architecture (stem-borne, shallow, and deep roots), anatomy (aerenchyma, vasculature), and cell wall reinforcements (suberin and lignin). I will describe our approach to the dissection of gene regulatory networks of specific cells that underlie plasticity in a changing environment. Our findings illuminate conservation and distinction in regulators and regulatory networks that provide opportunities for crop improvement.
Julia Bailey-Serres is Distinguished Professor of Genetics and Director of the Center for Plant Cell Biology at the University of California, Riverside. She is known for her research on plant adaptive responses to environmental stresses. Her group dissected the mechanisms of submergence tolerance provided by rice gene SUBMERGENCE 1A gene that now stabilizes grain yields in flood-prone paddies of Asia. She has guided discoveries into the mechanisms whereby plants sense, signal and respond to oxygen deficiency and energy stress. Her pioneering studies in RNA biology uncovered the importance of mRNA sequestration and translational control in response to and recovery from hypoxia and other stimuli. Through the inventive capture of mRNAs associated with ribosomes combined with chromatin profiling, her group has uncovered cell-specific metabolic and developmental plasticity to water extremes, nutrient deficiencies, and beneficial microbes in rice. Current research seeks to define and manipulate gene circuitry and mRNA translation that underlies adaptive plasticity to enhance multi-stress resilience, soil health, and global food security. Bailey-Serres is a fellow of the US National Academy of Sciences.