Acetobacter diazotrophicus, an Endophyte of Sugarcane, Promotes Plant Growth: Studies of Nitrogen Fixation, Phytochormone Production, and the Colonization Process

重氮营养菌Kennedy Acetobacter diazotrophicus是一种从世界各地种植的甘蔗中分离出来的固氮细菌。它栖息在甘蔗的内部空间，而不是它的外表面或附近的土壤。在PI的实验室中获得了这种细菌为植物生长提供固定氮的证据：接种了重氮养单胞杆菌的甘蔗植株比未接种的植株或接种了不能固定氮的突变体的植株生长得更好。这种共生关系为研究细菌固氮在禾草和谷物中的潜在效益提供了一个模型系统。目的是：1)确定向植物提供多少固定氮；2)了解重氮养单胞菌产生的生长激素是否也有利于植物生长；3)利用荧光标记的细菌表征重氮养双歧杆菌在甘蔗上的定殖。这一结果将为其他单株植物，如玉米、小麦或水稻如何从固氮细菌中受益提供见解。

9728184 Kennedy Acetobacter diazotrophicus is a nitrogen-fixing bacterium isolated from sugarcane grown throughout the world. It inhabits the interior spaces of sugarcane but not its outside surfaces or nearby soils. Evidence that this bacterium supplies fixed nitrogen for plant growth was obtained in the PI's laboratory: sugarcane plants inoculated with A. diazotrophicus grew better than did uninoculated plants or plants inoculated with mutants unable to fix nitrogen. This symbiosis provides a model system for studying the potential benefit of bacterial nitrogen fixation in grasses and cereals. The objectives are 1) to determine how much fixed N is supplied to the plants: 2) to learn whether production of growth hormones by A. diazotrophicus also benefits plant growth; and 3) to characterize how A. diazotrophicus colonizes sugarcane using bacteria tagged with fluorescent markers. The results will provide insight into how other monocots, such as corn, wheat or rice might benefit from nitrogen-fixing bacteria.