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

主要研究者：Jan Dvorak（加州大学戴维斯分校）共同主要研究者：Ming-Cheng Luo和帕特里克E. McGuire（加州大学戴维斯分校）、Muhammad Javed Iqbal（北达科他州州立大学）、Makhdoom Hussain（小麦研究所，费萨拉巴德，巴基斯坦）和Shahzada Munawar Mehdi（土壤盐分研究所，巴基斯坦）Rains（加州大学戴维斯分校）和Dennis Falaschi（Panoche Water District，菲尔堡，加利福尼亚州）盐度限制了世界上许多半干旱地区的农业。在该项目的伙伴国巴基斯坦，2 100万公顷土地中有200万公顷盐碱化，不适合或仅略适合农业。盐渍化土地可以通过适当的农艺措施和工程干预措施和/或种植耐盐作物加以改良。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不安地缓慢。该项目采取了一种相反的策略，通过改善植物的农艺属性，自然能够耐受盐。多年生高冰草及其近缘种具有特殊的耐盐性，有些高冰草可在盐碱环境中生产大量牧草。高麦草的一个独特的资产是，它们可以与小麦杂交，产生的植物材料往往是非常耐盐。虽然小麦和冰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染色体配对基因Ph 1突变的遗传原种来诱导。本项目的目的是评估利用Su 1-Ph 1（Suppressor of Ph 1）系统开发新的耐盐种质的可能性。利用细胞遗传学和遗传学方法以及矿物质含量、营养品质和农艺性状对从这些杂交培育出的双二倍体进行鉴定。将在加州和巴基斯坦进行实地评价。 为了进行遗传分析，将对冰草基因组进行测序，并开发冰草种质特异性遗传标记。该项目的影响将远远超出开发巴基斯坦盐碱地农业技术和材料的范围。将产生和传播关于小麦和外来染色体之间重组的遗传操作的基本知识，目的是生产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物种杂交，以产生具有改进的耐旱性、耐热性、耐寒性或耐涝性或具有新属性（如多年生生长习性）的新型谷物。该项目中开发的耐盐材料将促进未来发现控制小麦草高耐盐性的基因，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。冰草基因组序列和冰草遗传标记将分别保存在NCBI（http：www.ncbi.nlm.nih.gov）和项目网站上，链接分别为GrainGenes（http：//wheat.example.gov/GG2/index.shtml）和Gramene（http：www.gramene.org）。遗传材料将提供给国家植物种质系统和堪萨斯州立大学的小麦遗传和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.