CAREER: Photoprotection for Tolerance to Abiotic Stress: Discovery through Natural Genetic Variation

光合作用是维持地球生命的基本生化过程，它需要光能。任何环境压力，如寒冷、干旱或炎热，都会限制固定二氧化碳的数量，并触发光保护机制，以消散或避免吸收可能对细胞和整个植物造成损害的多余能量。光保护的生理和遗传方面已经在模式物种中进行了研究，但还没有研究将光保护作为一种有用的和改进的作物非生物逆境抗性机制。考虑到非生物胁迫是农业系统产量损失的主要原因，以及气候变化将产生更加极端的环境条件，利用光保护等新的非生物胁迫机制可能对作物生产力产生重大影响，从而对我们社会的繁荣产生重大影响。该项目的目标是利用高粱（一种重要的商业作物）的自然遗传变异，发现影响植物在逆境条件下应对过度能量能力的基因/分子标记。本项目包括以下具体目标：1)确定最大限度提高光保护响应的干旱和寒冷实验条件；2)利用连锁不平衡图谱（Linkage Disequilibrium， LD）检测光保护候选基因与光合和荧光的关联；3)发现与光保护变异相关的新基因/标记；4)鉴定候选基因、功能多态性和确定与高光保护能力相关的等位基因变异的表达水平。本项目的成果包括与优越的光保护能力相关的基因/标记和等位基因变异，这些基因的功能多态性和表达谱，以及可以在多种环境条件下测试并用于育种计划的分子标记。该项目还将为一名博士和一名本科生提供研究培训和指导。在向公众推广方面，项目将为Meta开发一个新的模块！Blast是一款实时3D动作冒险视频游戏，旨在让学生参与复杂生物系统的学习过程。“光保护”补充了当前的模块，并将重点关注光保护及其对社会的影响。这个游戏将被高中教师用于生物课程，也将被用于爱荷华州立大学（ISU）的本科课程。此外，该项目将分别在两年一度的爱荷华州农业进步展和国际农业联盟研究和示范农场上进行示范和推广介绍。由于参加这些活动的人数、他们在农业生产系统中的作用以及因此对社会的影响，这些向公众传播本项目所产生的知识的机会具有独特的价值。本项目使用的所有种质均可通过USDA-ARS国家遗传资源保护（NCGRP）免费获取。所有序列数据将存入NCBI GenBank的dbSNP和GSS数据库。所有表型数据将长期保存在USDA-ARS种质资源信息网络（GRIN） （http://www.ars-grin.gov/）。

Photosynthesis, the fundamental biochemical process sustaining life in this planet, requires light energy. Any environmental stress such as cold, drought or heat will limit the amount of fixed CO2, and trigger photoprotection mechanisms to dissipate or avoid absorption of excess energy that might cause damage to cells and the plant as a whole. The physiological and genetic aspects of photoprotection have been studied in model species but there has been no investigation of photoprotection as a useful and improvable mechanism of abiotic stress tolerance in crop species. Considering that abiotic stresses are the main cause of yield loss in agricultural systems, and that climate change will generate even more extreme environmental conditions, the utilization of a novel abiotic stress mechanism such as photoprotection could have a significant impact on crop productivity and thus on the prosperity of our society. The goal of this project is to discover genes/molecular markers affecting the plant's capacity to cope with excessive energy under stress conditions, using natural genetic variation in sorghum, a commercially important crop. This project includes the following specific aims: 1) to determine the drought and cold experimental conditions that would maximize the photoprotection response; 2) to test the association of photoprotection candidate genes with photosynthesis and fluorescence by Linkage Disequilibrium (LD) mapping; 3) to discover novel genes/markers associated with variation in photoprotection; and 4) to identify candidate genes, functional polymorphisms and determine expression levels of allelic variants associated with higher photoprotective capacity under stress. The outcomes of this project include genes/markers and allelic variants associated with superior photoprotective capacity, the functional polymorphisms and expression profiles of those genes, and molecular markers that could be tested under multiple environmental conditions and exploited in breeding programs. The project will also provide research training and mentoring for one PhD and one undergraduate student. With regard to outreach to the general public, the project will develop a new module for Meta!Blast, a real-time 3D action-adventure video game designed to engage students in the learning process of complex biological systems. "Photoprotection" complements current modules and will focus on photoprotection and its effects on society. This game will be utilized by high school teachers in biology courses but also in undergraduate courses at Iowa State University (ISU). In addition, the project will provide demonstrations and extension presentations at the biannual Iowa Farm Progress Show and the ISU Research and Demonstration Farms, respectively. These opportunities to disseminate knowledge generated in this project to the general public are uniquely valuable because of the number of people attending those events, their roles on agricultural production systems and therefore their impact on society. All germplasms used in this project are freely available through the USDA-ARS National Genetic Resources Preservation (NCGRP). All sequence data will be deposited in the NCBI GenBank dbSNP and GSS databases. All phenotypic data will be deposited long-term at the USDA-ARS Germplasm Resources Information Network (GRIN) (http://www.ars-grin.gov/).