U.S.-Brazil Cooperative Research: Genetic Analysis of Nitrogen Fixation in Acetobacter diazotrophicus, an Endophyte of Sugar Cane

美国-巴西合作研究：甘蔗内生菌固氮醋杆菌固氮的遗传分析

• 批准号: 9302788
• 负责人: Christina Kennedy
• 金额: $ 3.58万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-15 至 1997-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9302788&HistoricalAwards=false
• 关键词: U.S.; Brazil; Cooperative; Research; Genetic

9302788 Kennedy This U.S.-Brazil Program award will support the collaboration of Christina Kennedy of the University of Arizona and Johanna Dobereiner of EMBRAPA in Rio de Janeiro, Brazil. The project aims to isolate and mutate genes of Azobacter diazotrophicus necessary for nitrogenase enzyme activity. Nitrogen-fixing bacteria have been isolated from sugar cane varieties in Brazil in which up to 70 percent of total plant nitrogen comes from atmospheric nitrogen (dinitrogen). The major organism isolated, A. diazotrophicus, is an endophyte thought to be responsible for the fixation of dinitrogen and transfer of products to the plant system. The researchers will use mutants unable to fix nitrogen to prove or disprove a role for this species in providing fixed nitrogen in sugar cane. They will also characterize genes involved in bacterial responses to environmental factors such as ammonia and oxygen that control nitrogenase biosynthesis. Strategies to increase amounts of fixed nitrogen provided to plants will be applied to construct strains that produce nitrogenase in the presence of ammonia or have increased tolerance to oxygen. The U.S. side has expertise in the genetics of nitrogen-fixing bacteria. The Brazilian laboratory is where A. diazotrophicus was identified and its colonization of plants is being studied. Both sides will benefit from establishing the significance of a novel and potentially important nitrogen-fixing bacterial species. ***

9302788 Kennedy 该美国-巴西项目奖将支持亚利桑那大学的 Christina Kennedy 和巴西里约热内卢 EMBRAPA 的 Johanna Dobereiner 的合作。 该项目旨在分离和突变固氮固氮菌中固氮酶活性所必需的基因。 已从巴西的甘蔗品种中分离出固氮细菌，其中高达 70% 的植物总氮来自大气中的氮（二氮）。 分离出的主要生物体固氮放线菌是一种内生菌，被认为负责固氮并将产物转移至植物系统。 研究人员将使用无法固氮的突变体来证明或反驳该物种在甘蔗中提供固氮的作用。 他们还将表征参与细菌对环境因素（例如控制固氮酶生物合成的氨和氧）的反应的基因。 增加向植物提供的固定氮量的策略将应用于构建在氨存在下产生固氮酶或具有增强的氧耐受性的菌株。 美方在固氮细菌遗传学方面拥有专业知识。 巴西实验室是鉴定固氮固氮菌的地方，并且正在研究它在植物中的定殖。 双方都将从确立一种新型且潜在重要的固氮细菌物种的重要性中受益。 ***