BREAD: An Alternate Dwarfing Gene System to Improve Abiotic Stress Tolerance in Cereals

PI：Kulvinder S. Gill（华盛顿州立大学）CoPIs：Johar Singh（旁遮普农业大学，印度卢迪亚纳）和Devinder Sandhu（威斯康星大学史蒂文斯点）主要合作者：Kanwarpal S. Dhugga（Pioneer Hi-Bred International，Inc.），Gurmukh S. Johal（普渡大学）、Mustafa Shafqat（巴基斯坦阿伯塔巴德COMSATS大学）、Harindra S. Balyan和Pushpendra K. Gupta（印度密拉特大学）和Madhu Meeta Jindal（印度卢迪亚纳旁遮普农业大学）影响植物高度的基因使小麦和水稻产量翻了一番，从而彻底改变了农业。在环境胁迫条件下，小麦半矮秆突变体rht 1和rht 2表现出对农艺性状的不利影响，包括胚芽鞘和第一叶长、根长和生物量，以及耐旱性。这些不利影响限制了在非生物胁迫条件下的小麦产量，非生物胁迫条件经常影响超过85%的美国和约50%的世界小麦生产区。该项目的主要目标是确定和表征小麦和其他谷物的替代矮化基因系统，以减轻目前使用的矮化基因的不利影响。 目前在小麦中使用的矮化基因系统通过中断植物生长激素赤霉素的产生或信号传导来降低植株高度，赤霉素对于植物应对胁迫条件特别重要。 先前的研究表明，在玉米brachytic 2（br 2）和高粱dwarf 3（dw 3）基因编码的P-糖蛋白（PGP）参与极性运输的生长素，突变导致植物高度的降低，没有任何不利的表型效应通常与目前使用的小麦矮化突变体。 基于这些观察，本项目将测试玉米Br 2基因的小麦直系同源物（TaBr 2）是否可以用作小麦中的替代矮化基因系统。 具体目标是克隆TaBr 2，并使用各种反向遗传学工具，包括病毒诱导的基因沉默和RNAi，研究其在小麦中的表达和功能。 此外，将使用表型以及通过TILLING筛选分离TaBr 2中的突变，以鉴定理想的矮化突变体。 该项目的好处，特别是对拥有小块土地的农民来说，将来自增值基因的渗入，包括抗条锈病基因以及新开发的矮化基因突变体，进入印度，巴基斯坦和美国的流行品种。 此外，该项目将为作物植物中生长素信号传导和运输过程提供新的见解。 该项目将为本科生和研究生以及研究助理/访问科学家提供高度跨学科和国际研究培训机会。 PI积极参与外展活动，包括农民田间日，与种植者团体交谈，并为种植者团体和广大公众组织实验室演示和展示。项目信息和调查结果将通过这些努力以及电子手段与公众沟通。 将开发一个项目网站，作为获取该项目产生的所有资源的“一站式”网站。 还将提供从每个研究者网页到该项目网页的链接。 表达和序列数据将立即提交至GenBank（http：//www.ncbi.nlm.nih.gov/），根据目前接受的社区标准（例如Bermuda/Ft.劳德代尔协定）。将首先通过出版物，然后通过项目网页和Gramene（http：//www.gramene.org/）免费提供各种小麦品系上选定基因的实时表达数据。图谱数据可在GrainGenes数据库（http：//wheat.tag.usda.gov/GG2/index.shtml）查阅。 本项目中产生的所有VIGS和RNAi构建体和种质将保存在PI的实验室中，并将向公众提供。 在印度和巴基斯坦开发的基因渗入系将在通过各自国家的品种测试计划后作为公共品种发布。 在美国开发的渐渗系将作为公共品种发布，可能通过USDA-ARS国家遗传资源保护中心和植物品种保护办公室。

PI: Kulvinder S. Gill (Washington State University)CoPIs: Johar Singh (Punjab Agricultural University, Ludhiana, India) and Devinder Sandhu (University of Wisconsin-Stevens Point)Key Collaborators: Kanwarpal S. Dhugga (Pioneer Hi-Bred International, Inc.), Gurmukh S. Johal (Purdue University), Mustafa Shafqat (COMSATS University, Abbottabad, Pakistan), Harindra S. Balyan and Pushpendra K. Gupta (Meerut University, India), and Madhu Meeta Jindal (Punjab Agricultural University, Ludhiana, India)Genes influencing plant height have revolutionized agriculture by doubling the wheat and rice production. Under conditions of environmental stress, the most predominantly used wheat semi-dwarf mutants rht1 and rht2 exhibit adverse effects on agronomic traits including coleoptile and first leaf length, root length and biomass, as well as drought tolerance. These adverse effects limit wheat yields under abiotic stress conditions that regularly affect more than 85% of the US and about 50% of the world wheat production area. The main goal of the project is to identify and characterize an alternative dwarfing gene system for wheat and other cereals in order to alleviate adverse effects of the currently used dwarfing genes. Currently used dwarfing gene systems in wheat reduce plant height by interrupting production or signaling of plant growth hormone gibberellins that are particularly important for plants to deal with stressful conditions. Previous studies have shown that mutations in the maize brachytic2 (br2) and the sorghum dwarf3 (dw3) genes that encode P-glycoproteins (PGPs) involved in polar transport of auxin, result in a reduction in plant height without any of the adverse phenotypic effects usually associated with the currently used wheat dwarfing mutants. Based on these observations, this project will test whether the wheat ortholog (TaBr2) of the maize Br2 gene can be used as an alternative dwarfing gene system in wheat. Specific objectives are to clone TaBr2 and to study its expression and function in wheat using various reverse genetics tools including virus-induced gene silencing and RNAi. In addition, mutations in TaBr2 will be isolated using phenotypic as well as by TILLING screens in order to identify the ideal dwarfing mutant. The benefit of the project, especially to farmers with small land holdings, will come from the introgression of value-added genes, including stripe rust resistance genes as well as newly-developed dwarfing gene mutants, into popular varieties of India, Pakistan, and the US. In addition, the project will provide new insight into the process of auxin signaling and transport in crop plants. The project will provide highly interdisciplinary and international research training opportunities for undergraduate and graduate students, as well as for research associates/visiting scientists. The PIs are actively involved in outreach activities including farmers' Field Days, talking to grower groups and organizing lab demonstrations and displays to grower groups and the public at large. The project information and findings will be communicated with the public via these efforts as well as through electronic means. A project website will be developed that will serve as a "one-stop" location for access to all resources generated in this project. Links will be provided to this project webpage from each of the investigator's web pages as well. Expression and sequence data will be immediately submitted to GenBank (http://www.ncbi.nlm.nih.gov/), according to the currently accepted community standard (e.g. Bermuda/Ft. Lauderdale agreement). Real-time expression data of selected genes on various wheat lines will be made freely available first via publications and then by hosting on the project webpage and on Gramene (http://www.gramene.org/). Mapping data will be available at GrainGenes database (http://wheat.pw.usda.gov/GG2/index.shtml). All VIGS and RNAi constructs and germplasm generated in this project will be maintained in the PIs' lab and will be available to the public. Gene introgression lines developed in India and Pakistan will be released as public varieties after going through variety testing programs of the respective countries. Introgression lines developed in the US will be released as public varieties, possibly through the USDA-ARS National Center for Genetic Resources Preservation and the Plant Variety Protection Office.