BREAD: Development of Novel Salt-tolerant Forage and Cereal Crops

PI: Jan Dvorak（加州大学戴维斯分校）合作PI: Ming-Cheng Luo和Patrick E. McGuire（加州大学戴维斯分校），Muhammad Javed Iqbal（北达科他州立大学），Makhdoom Hussain（巴基斯坦Faisalabad小麦研究所）和Shahzada Munawar Mehdi（巴基斯坦土壤盐分研究所）Edward J. DePeters， Emanuel Epstein和William D. Rains（加州大学戴维斯分校），以及Dennis Falaschi（加利福尼亚州Firebaugh的Panoche水区）盐度限制了世界上许多半干旱地区的农业。在这个项目的伙伴国巴基斯坦，总共2100万公顷的土地中有200万公顷盐碱化，不适合或勉强适合农业。盐碱化土地可以通过适当的农艺做法和工程干预和/或种植耐盐作物来复垦。不幸的是，由于主要作物固有的盐敏感性，其耐盐性的提高一直令人失望地缓慢。这个项目采取了一种相反的策略，通过提高植物的农艺属性来自然地耐受盐分。多年生高麦草及其近缘种具有特殊的耐盐性，有些在盐碱环境中生产大量的牧草。高麦草的一个独特优势是它们可以与小麦杂交，从而产生通常特别耐盐的植物材料。虽然小麦和小麦草的染色体不会自然重组，但这些物种的染色体之间的重组可以通过使用含有同源配对基因Ph1突变的遗传资源来诱导。本项目的目的是利用小麦与小麦杂交的Su1-Ph1 （Ph1抑制因子）系统，评估利用重组基因组开发新型耐盐种质的可能性。由这些杂交发育的两倍体将通过细胞遗传学和遗传方法以及矿物质含量、营养品质和农艺性状来表征。实地评价将在加利福尼亚和巴基斯坦进行。在遗传分析方面，将对小麦草基因组进行测序，并开发小麦草种质的特异性遗传标记。这个项目的影响将远远超出开发巴基斯坦盐碱地农业的技术和材料。关于小麦与外来染色体重组的遗传操作的基本知识将被生成和传播，目的是产生具有重组基因组的新植物形式。这些知识可以用于小麦与小麦草以外的其他品种的杂交，以生产具有更好的耐旱、耐热、耐寒或耐涝能力或具有新属性（如多年生生长习惯）的新型谷物。该项目开发的耐盐材料将有助于未来发现小麦草中控制高耐盐性的基因，并将其应用于小麦和其他作物的生物技术，此外还将在巴基斯坦和其他盐碱地国家的育种计划中立即使用该种质资源。小麦草基因组序列和小麦草遗传标记将分别存放在NCBI （http://www.ncbi.nlm.nih.gov)and，项目网站上有GrainGenes （http://wheat.pw.usda.gov/GG2/index.shtml）和Gramene （http://www.gramene.org）的链接）。遗传材料将提供给美国国家植物种质系统和堪萨斯州立大学小麦遗传与基因组资源中心进行长期储存和分配。

PI: Jan Dvorak (University of California, Davis)Co-PIs: Ming-Cheng Luo and Patrick E. McGuire (University of California-Davis), Muhammad Javed Iqbal (North Dakota State University), Makhdoom Hussain (Wheat Research Institute, Faisalabad, Pakistan), and Shahzada Munawar Mehdi (Soil Salinity Research Institute, Pakistan)Collaborators: Edward J. DePeters, Emanuel Epstein, and William D. Rains (University of California-Davis), and Dennis Falaschi (Panoche Water District, Firebaugh, CA) Salinity limits agriculture in many semiarid areas of the world. In Pakistan, the partner country of this project, two million hectares (ha) of the total 21 million ha of land are salinized and are either unsuitable or only marginally suitable for agriculture. Salinized land can be reclaimed with appropriate agronomic practices and engineering interventions and/or by growing salt-tolerant crops. Unfortunately, improvement of salinity tolerance of major crops has been disappointingly slow because of their inherent salt sensitivity. This project takes a reverse strategy by improving agronomic attributes of plants naturally able to tolerate salinity. Perennial tall wheatgrasses and their close relatives have exceptional salt tolerance and some produce a large quantity of forage in saline environments. A unique asset of tall wheatgrasses is that they can be hybridized with wheat, producing plant materials that are often exceptionally salt tolerant. While the chromosomes of wheat and wheatgrasses do not recombine naturally, recombination between chromosomes of these species can be induced through the use of genetic stocks containing mutations in the homoeologous pairing gene Ph1. The goal of this project is to evaluate the possibility of developing novel salt-tolerant germplasm with recombined genomes derived from hybridization between wheatgrass and wheat using the Su1-Ph1 (Suppressor of Ph1) system. Amphiploids developed from these crosses will be characterized by cytogenetic and genetic approaches as well as for mineral content, nutritional quality, and agronomic traits. Field evaluations will be conducted in California and in Pakistan. For genetic analysis, wheatgrass genomes will be sequenced and genetic markers specific for wheatgrass germplasm will be developed. This project will have an impact reaching far beyond developing technology and materials for agriculture on saline soils in Pakistan. Basic knowledge about genetic manipulation of recombination between wheat and alien chromosomes with the objective of producing novel plant forms with recombined genomes will be generated and disseminated. This knowledge can be deployed in hybridization of wheat with species other than wheatgrasses in order to produce novel cereals with improved tolerance of drought, heat, cold, or waterlogging or with novel attributes, such as perennial growth habit. The salt-tolerant materials developed in this project will facilitate future discovery of genes controlling high salt tolerance in wheatgrasses and their deployment in biotechnology of wheat and other crops in addition to the immediate use of this germplasm in breeding programs in Pakistan and other countries with saline soils. Wheatgrass genome sequences and the wheatgrass genetic markers will be deposited at NCBI (http://www.ncbi.nlm.nih.gov)and on the project website with links in GrainGenes (http://wheat.pw.usda.gov/GG2/index.shtml) and Gramene (http://www.gramene.org), respectively. Genetic materials will be offered for long term storage and distribution to the National Plant Germplasm System and the Wheat Genetic and Genomic Resources Center, Kansas State University.