EAGER: Elucidating Rhizobial Interactions and the Possibility of Symbiotic Nitrogen Fixation in Non-nodulating Legume Gleditsia Triacanthos L.

EAGER：阐明非结瘤豆科植物皂角根瘤菌相互作用和共生固氮的可能性。

• 批准号: 1519900
• 负责人: Gyaneshwar Prasad
• 金额: $ 28.57万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1519900&HistoricalAwards=false
• 关键词: EAGER; Elucidating; Rhizobial; Interactions; Possibility

Nitrogen (N) is one of the most limiting nutrients for the growth of many plants though it is abundant in the atmosphere. Modern agriculture depends upon chemical N fertilizers that cause extensive environmental damage and are not sustainable. In contrast to the majority of crops, legumes (such as soybean, bean, lentils, alfalfa) form symbiotic associations with soil bacteria, resulting in the formation of nodules in which the bacteria accumulate in high numbers and fix atmospheric N for the plant. Because of N-fixing ability, legumes play an important role in sustainability in both agricultural and natural environments. However, many tree legumes do not form nodules and are thus considered non-N fixing. Many non-nodulating legumes are important components of various ecological systems and are increasingly being used for land reclamation and as biofuel crops. Increased understanding of the mechanisms by which non-nodulating legumes obtain their nitrogen will be crucial in improving the utilization of these legumes in nutrient-poor soils. The project will provide opportunities to undergraduate students and a post-doctoral fellow to train in both microbial and plant biology, especially as they relate to plant-microbial interactions. The benefits of research on microbial symbioses will also be emphasized in the urban agriculture initiative at UW Milwaukee. Legumes are by far the largest contributors of biologically fixed N2 to pristine environments. Although nodulation is often considered to be a distinguishing characteristic of legumes, a large number of species are not known to nodulate. Non-nodulating legumes live in the same native environments as their nodulating 'cousins' and yet have the same in planta N concentrations. Very little , however, is known about the mechanisms of N-acquisition in non-nodulated legumes. This project will explore the hypothesis that non-nodulating legume honey locust (Gleditsia triacanthos L.) possesses the potential for symbiotic N2 fixation with rhizobia. Preliminary data from the investigator's laboratory shows the presence of nodule-like structures on the roots of G. triacanthos that contained rhizobia. This project will (i) Elucidate the extent and mechanism of rhizobial colonization in G. triacanthos, (ii) Determine the response of G. triacanthos to rhizobial infection and (iii) Determine the potential of N2-fixation in the G. triacanthos-rhizobial association. In the long term, the results of this project could pave the way to improve N nutrition of non-legumes, including cereal crops that do not form N-fixing symbiosis.

氮（N）虽然在大气中含量丰富，但它是对许多植物生长最具限制性的营养物质之一。现代农业依赖于化学氮肥，造成广泛的环境破坏，是不可持续的。与大多数作物不同，豆类（如大豆、菜豆、扁豆、苜蓿）与土壤细菌形成共生关系，导致形成根瘤，其中细菌大量积累，并为植物固定大气氮。由于固氮能力，豆科植物在农业和自然环境的可持续性中发挥着重要作用。然而，许多豆科树种不形成根瘤，因此被认为是非固氮植物。许多非豆科植物是各种生态系统的重要组成部分，越来越多地用于土地开垦和作为生物燃料作物。提高对非豆科植物获得氮的机制的理解，将是至关重要的，在提高这些豆类作物在养分贫乏的土壤中的利用。该项目将为本科生和博士后研究员提供微生物和植物生物学培训的机会，特别是因为它们与植物-微生物相互作用有关。在密尔沃基大学的城市农业计划中，也将强调微生物共生研究的好处。豆科植物是迄今为止最大的贡献者生物固定N2的原始环境。虽然通常认为植物的一个显著特征是有分枝，但许多物种并不知道它们有分枝。非生长豆科植物与其生长“表亲”生活在相同的原生环境中，但植物体内的氮浓度相同。然而，很少有人知道的N-收购的机制，在非豆科植物。本研究旨在探讨非结球豆科植物皂荚（Gleditsia triacanthos L.）具有与根瘤菌共生固氮的潜力。来自研究者实验室的初步数据显示，在G.含有根瘤菌的三棘藻。本研究的主要目的是：（1）阐明根瘤菌在G. triacanthos，（ii）测定G. triacanthos根瘤菌感染和（iii）确定固氮的潜力，在G。三棘藻-根瘤菌群丛从长远来看，该项目的结果可以为改善非豆类作物的氮素营养铺平道路，包括不形成固氮共生的谷类作物。