Molecular mechanisms of ABA biosynthesis under drought stress

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。作者：朱建华jhzhu@umd.edu（首席研究员）提案号：0919745提案题目：干旱胁迫下ABA生物合成的分子机制摘要由土壤水分亏缺引起的干旱是导致全球作物生产力严重损失的最常见的环境因素之一。植物激素脱落酸（ABA）是控制植物非生物胁迫反应的重要因子。因此，ABA被称为应激激素。虽然ABA积累本身是对干旱胁迫的一种众所周知的反应，但控制ABA积累并将ABA与下游反应联系起来的分子因素在很大程度上是未知的。本项目旨在通过对干旱胁迫诱导的ABA积累和耐旱性缺陷拟南芥突变体的正向遗传分析，了解干旱胁迫下ABA生物合成的分子调控机制。这些突变体最初是基于9-顺式环氧类胡萝卜素双加氧酶3 （NCED3）基因表达的改变而分离出来的。在拟南芥中，NCED3是干旱胁迫诱导的ABA合成的限速酶，控制该基因表达的蛋白质可能在调节ABA生物合成的传感和信号通路的早期事件中发挥重要作用。作为该项目的一部分进行的研究将大大提高我们对ABA生物合成如何在分子水平上受到调节的理解，并可能导致识别更多的ABA传感器。这可能有助于设计和实施新的抗旱作物工程策略。该项目将对教育和外联活动产生重要影响。教育和推广由两部分组成：a)向研究生和高级本科生提供功能基因组学知识，这些学生目前正在马里兰大学教授首席研究员的课程；b)每年为在传统黑人本科院校就读的学生提供一次暑期实习机会。教育和推广的目标是为当前和未来的科学家提供理解和研究植物非生物胁迫反应的分子遗传学专业知识。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Investigator (s): Jianhua Zhu jhzhu@umd.edu (principal investigator)Proposal number: 0919745Proposal title: Molecular mechanisms of ABA biosynthesis under drought stressAbstractDrought 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.