BREAD: Inactivating Rust Resistance Suppressors to Unlock Multiple Defense Responses in Wheat

主要研究者：Li Huang（Montana州立大学）CoPI：Evans Lagudah（CSIRO Plant Industry-Black Mountain，Australia）合作者：琳达塔贝（CSIRO Plant Industry-Black Mountain，Australia），彭俊华（中国科学院武汉植物园/研究所，中国武汉）和Davinder Singh（CIMMYT，Village Market，内罗毕，肯尼亚）小麦是世界上大多数人口的主食谷物。据估计，世界上大约50%的小麦种植在发展中国家，在那里它是很大一部分自给农民的主食。锈病是真菌病原体，导致小麦的一些最具破坏性的疾病。叶锈病（由小麦柄锈菌（Puccinia triticina）引起）、茎锈病（由禾柄锈菌（P. graminis f.）小麦条锈菌（P. striiformis f.）sp. triangulae）是分布最广的小麦病害。这些病害降低植物适合度并导致谷物产量损失5- 95%，这取决于锈菌种类和它感染作物的发育阶段。 从历史上看，培育对锈病的持久抗性在很大程度上依赖于不断将新的抗性基因渗入适应品种，通常来自野生亲缘。这个漫长的遗传过程并不总是能完全成功地消除连锁阻力带来的不利特征。此外，有遗传证据表明，渗入的抗性基因的功能往往被抑制在六倍体小麦遗传背景。 然而，人们对这些“抑制因子”的性质或它们的作用机制知之甚少。 该项目将调查小麦抗锈性的两种抑制因子，初步研究表明，当灭活时，会发现对新出现的毒性茎锈病菌株Ug 99的强大抗性，该菌株目前威胁着非洲和中东的粮食安全。 该项目将部署一个多国小组，1）描述这两种抑制因子及其作用机制; 2）将这种新的抗性转移到肯尼亚和中国的小麦育种计划中;并且，在本发明中，第三章在这一广阔的区域内筛选项目种质以抵抗其他新出现的锈病威胁。这项工作有可能解开六倍体小麦中大量隐藏的抗锈病基因这些基因组要么是目前未被认识到的，要么是利用不足的。抗锈性抑制剂尚未在任何实验系统中进行表征，因此项目结果将提供有关以前未研究的一类植物防御反应负调节剂的性质和作用模式的基本新信息。 这项研究将通过提供新的、有用的抗锈病来源以及相关的分子标记，对发展中国家的农业产生直接的好处。在培训和推广方面，该项目将提供一个交流项目，向肯尼亚和中国的年轻研究人员介绍尖端技术，并为美国和澳大利亚的年轻研究人员创造机会，学习肯尼亚和中国的当地知识。该交流项目将培训四名年轻科学家，他们将在肯尼亚和中国的两个实验室工作，提供品种并教育他们国家的小农。此外，该项目还将制作三个视频协议，供在线使用，以接触更广泛的受众，包括发达国家和发展中国家的学生、生物教师和小麦育种者。 该项目产生的所有数据和生物资源将向公众开放。 基因表达数据将提交至基因表达综合数据库（GEO; http：//www.ncbi.nlm.nih.gov/geo/）。 图谱和标记数据将提交给GrainGenes（http：//wheat.usda.gov/GG2/index.shtml），种质和育种系信息将通过美国农业部-国家粮食和农业研究所支持的小麦持久抗锈性（DRRW）项目网站（http：//maswheat.ucdavis.edu/）提供。 该项目使用和/或开发的小麦品系将通过USDA-ARS国家小谷物收集中心（NSGC）提供。

PI: Li Huang (Montana State University)CoPI: Evans Lagudah (CSIRO Plant Industry-Black Mountain, Australia)Collaborators: Linda Tabe (CSIRO Plant Industry-Black Mountain, Australia), Junhua Peng (Chinese Academy of Sciences, Wuhan Botanical Garden/Institute, Wuhan, China) and Davinder Singh (CIMMYT, Village Market, Nairobi, Kenya)Wheat is a staple cereal for most of the world's population. It is estimated that approximately 50% of the world's wheat is grown in developing countries, where it serves as a staple food for a large proportion of subsistence farmers. Rusts are fungal pathogens that cause some of the most damaging diseases of wheat. Leaf rust (caused by Puccinia triticina), stem rust (caused by P. graminis f. sp. tritici) and stripe rust (caused by P. striiformis f. sp. tritici) are the most widely distributed diseases of wheat. These diseases reduce plant fitness and result in grain yield losses from 5-95%, depending on the rust species and the development stage at which it infects the crop. Historically, breeding durable resistance to rust diseases relies largely on continually introgressing new resistance genes into adapted varieties, often from wild relatives. This long genetic process is not always completely successful in eliminating unfavorable characteristics brought in by linkage drag. Furthermore, there is genetic evidence that the functions of introgressed resistance genes are often suppressed in the hexaploid wheat genetic background. However, little is known about the nature of these "suppressors" or the mechanism by which they act. This project will investigate two suppressors of rust resistance in wheat that preliminary studies have shown, when inactivated, unmask robust resistance to the newly emerged virulent stem rust strain, Ug99, which currently threatens food security in Africa and the Middle East. The project will deploy a multi-national team to 1) characterize these two suppressors and their mechanism of action(s); 2) transfer this new resistance to wheat breeding programs in both Kenya and China; and, 3) screen project germplasm for resistance against other emerging rust disease threats across this broad region.The work has the potential to unlock an extensive array of cryptic rust resistance genes in the hexaploid wheat genome that are either currently unrecognized or have been poorly utilized. Suppressors of rust resistance have not been characterized in any experimental system, so project results will provide fundamental new information about the nature and mode of action of a previously-unstudied class of negative regulators of plant defense responses. This research will have direct benefits for agriculture in the developing world by providing new, useful sources of rust resistance, with associated molecular markers. With respect to training and outreach, the project will provide an exchange program to introduce young researchers from Kenya and China to cutting-edge technologies, and to create opportunities for young researchers from the USA and Australia to learn from local knowledge in Kenya and China. The exchange program will train four young scientists who will work in the two labs in Kenya and China to deliver cultivars and to educate smallholder farmers of their nations. In addition, the project will generate three video protocols available on-line to reach a broader audience, including students, biology teachers, and wheat breeders in both developed and developing countries. All data and biological resources generated by the project will be available to the public. Gene expression data will be submitted to the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo/). Mapping and marker data will be submitted to GrainGenes (http://wheat.pw.usda.gov/GG2/index.shtml) and germplasm and breeding line information will be available through the website for the USDA-National Institute of Food and Agriculture supported Durable Rust Resistance in Wheat (DRRW) project (http://maswheat.ucdavis.edu/). Wheat lines used and/or developed by this project will be available through the USDA-ARS National Small Grain Collection (NSGC).