Drought resulting from soil water deficit is one of the most common environmental factors that lead to substantial losses in productivity of crops worldwide. The phytohormone abscisic acid (ABA) is a very important factor in controlling abiotic stress responses in plants. Therefore, ABA is referred to as a stress hormone. While ABA accumulation itself is a well known response to drought stress, the molecular factors that control ABA accumulation and connect ABA to downstream responses are largely unknown. This project includes work that aims to understand the molecular mechanisms regulating ABA biosynthesis under drought stress by using forward genetic analysis of Arabidopsis mutants defective in drought stress-induced ABA accumulation and drought tolerance. These mutants were originally isolated based on altered expression of the 9-cis-epoxycarotenoid dioxygenase 3 (NCED3) gene. In Arabidopsis, NCED3 is a rate limiting enzyme in drought stress-induced ABA synthesis and proteins that control expression of this gene are likely to play important roles in early events of the sensing and signaling pathways that regulate ABA biosynthesis. The research undertaken as part of this project will significantly advance our understanding of how ABA biosynthesis is regulated at the molecular level, and perhaps lead to the identification of additional ABA sensors. This could assist in designing and implementing new strategies for engineering drought tolerant crops.
The project will have important impacts on education and outreach. The education and outreach is composed of two parts: a) Delivery of knowledge of functional genomics to graduate and advanced undergraduate students in courses which the Principal Investigator is currently teaching at the University of Maryland; b) Offering one summer internship per year to a student enrolled at a historically black undergraduate institution. The goal of education and outreach is to provide current and future scientists with understanding and research expertise in molecular genetics of plant abiotic stress responses.
