Joint NSF/ERA-CAPS: Mechanisms of Natural Variation in Maize Herbivore Resistance

PI: Georg Jander（博伊斯·汤普森植物研究所）高级人员：Tiffany Fleming（博伊斯·汤普森植物研究所）ERA-CAPS合作者：Matthias Erb（瑞士伯尔尼大学）、Monika Frey（德国慕尼黑工业大学）、Inge Fomsgaard（丹麦奥胡斯大学）和Jurriaan Ton（英国谢菲尔德大学）玉米（Zea mays）是世界上产量最高的粮食作物，受到90多种昆虫食草动物的攻击。尽管玉米对草食的抗性存在广泛的差异，但对玉米品种之间这些差异的潜在遗传基础知之甚少。遗传作图、转录谱分析、昆虫生物测定和生化方法将用于鉴定玉米草食抗性基因。该项目的一个特别重点领域将是鉴定促进苯并恶嗪类物质生产和运输的生物合成和调节基因，苯并恶嗪类物质是玉米、小麦、黑麦、野生大麦和其他禾本科植物中具有重要防御功能的一类次生代谢物。玉米苯并恶嗪类代谢的研究将为研究这些重要的农业和生态植物代谢产物提供一个可操作的模型系统。利用一组不同的玉米自交系进行遗传作图将鉴定出有助于抗蚜虫和抗毛虫的新基因。鉴于玉米植物保护自己免受各种害虫和病原体的侵害，在已确定的防御途径之间可能存在相互作用。将通过比较已鉴定的玉米基因的基因组位置和生化功能来检测防御协同作用和权衡，这些基因有助于草食动物抗性的自然变异。这个项目将导致鉴定以前未知的影响植物-食草动物相互作用的玉米基因。潜在的代谢限制和权衡在玉米防御不同种类的昆虫食草动物将被记录。预计这些预期的结果将为利用分子育种和转基因方法提高玉米（美国最重要的农作物）的抗草食性开辟新的机会。通过这个项目进行的研究将有助于培养新一代的学生和博士后，为未来在学术界、工业界或政府部门的职业生涯做准备。与欧洲ERA-CAPS （http://www.eracaps.org/）伙伴项目“1,4-苯并恶嗪-3-酮作为植物生物相互作用决定因素的生物合成、运输和分泌（BENZEX）”的国际研究交流将加强对学生和博士后的培训。涉及玉米和草食动物相互作用的实验将完全纳入博伊斯·汤普森研究所已建立的教育和推广计划。来自美国各地的本科生将被招募参加为期十周的暑期实习项目。在为期一周的培训课程中，来自资源不足学校的生物教师将为他们的课程开发新的植物科学模块。在当地科学教室中进行毛毛虫摄食分析的实验包不仅可以为学生提供实践研究经验，还可以为玉米抵御食草昆虫的机制提供新的信息。通过这个项目产生的所有数据和资源都将向公众开放。该项目的一个主要产出将是一个公开可用的工具包，用于研究苯并恶嗪类药物在玉米抵御食草动物和病原体方面的作用。近等基因系和突变体的种子将存放在玉米遗传合作库存中心，DNA克隆将根据要求提供，检测方法将在科学期刊上发表。所有的DNA序列将存储在公共数据库中，如NCBI SRA、Gramene和MaizeGDB。代谢物和代谢组学数据将存储在METLIN （http://metlin.scripps.edu/）。教育和宣传材料将通过博伊斯·汤普森研究所网站（http://bti.cornell.edu/education/）发布并供使用。

PI: Georg Jander (Boyce Thompson Institute for Plant Research)Senior Personnel: Tiffany Fleming (Boyce Thompson Institute for Plant Research)ERA-CAPS collaborators: Matthias Erb (University of Bern, Switzerland), Monika Frey (Technical University of Munich, Germany), Inge Fomsgaard (Aarhus University, Denmark), and Jurriaan Ton (University of Sheffield, United Kingdom)Maize (Zea mays), the world's most productive grain crop, is attacked by more than 90 species of insect herbivores. Although there is wide variation in maize resistance to herbivory, very little is known about the underlying genetic basis of these differences among maize cultivars. Genetic mapping, transcript profiling, insect bioassays, and biochemical approaches will be used to identify maize herbivore resistance genes. A particular focus area of this project will be the identification of biosynthetic and regulatory genes contributing to the production and transport of benzoxazinoids, a class of secondary metabolites with important defensive functions in maize, wheat, rye, wild barley, and other grasses. Research involving maize benzoxazinoid metabolism will provide a tractable model system for studying these agriculturally and ecologically important plant metabolites. Genetic mapping using a panel of diverse maize inbred lines will identify novel genes contributing to aphid and caterpillar resistance. Given the wide array of pests and pathogens against which maize plants protect themselves, there are likely to be interactions among the identified defense pathways. Defensive synergies and tradeoffs will be detected by comparing the genomic locations and biochemical functions of the identified maize genes that contribute to natural variation in herbivore resistance. This project will lead to the identification of previously unknown maize genes that influence plant-herbivore interactions. Potential metabolic limitations and tradeoffs in maize defense against different classes of insect herbivores will be documented. It is anticipated that these expected results will open up new opportunities for using molecular breeding and transgenic approaches to improve herbivore resistance in maize, the most important agricultural crop in the United States. Research conducted through this project will help to train a new generation of students and postdocs for future careers in academia, industry, or government service. International research exchanges with the European ERA-CAPS (http://www.eracaps.org/) companion project entitled "Biosynthesis, transport and exudation of 1,4-benzoxazin-3-ones as determinants of plant biotic interactions (BENZEX)" will enhance the training of students and postdocs. Experiments involving maize-herbivore interactions will be fully integrated into an established education and outreach program at the Boyce Thompson Institute. Undergraduate students from throughout the United States will be recruited to be part of a ten-week summer internship program. In one-week training sessions, biology teachers from under-resourced schools will develop new plant science modules for their classes. Experimental kits for conducting caterpillar-feeding assays in local science classrooms will not only provide students with hands-on research experience, but also generate new information about the mechanisms of maize defense against insect herbivory. All data and resources generated through this project will be publicly accessible. A major output of this project will be a publicly available toolkit for studying the role of benzoxazinoids in maize defense against herbivores and pathogens. Seeds of near-isogenic lines and mutants will be deposited in the Maize Genetics Cooperation stock center, DNA clones will be available upon request and assay methods will be published in scientific journals. All DNA sequences will be deposited in public databases such as the NCBI SRA, Gramene, and MaizeGDB. Metabolite and metabolomics data will be deposited at METLIN (http://metlin.scripps.edu/). Education and outreach materials will be published and available for use via the Boyce Thompson Institute website (http://bti.cornell.edu/education/).