SGER: Identification of Eukaryotic Genes Required for Nitrogen Fixation

SGER：固氮所需真核基因的鉴定

• 批准号: 0838091
• 负责人: Sharon Doty
• 金额: $ 1.3万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838091&HistoricalAwards=false
• 关键词: SGER; Identification; Eukaryotic; Genes; Required

While studying the nitrogen-fixing endophytes within poplar trees, the profound discovery was made that some of the isolates were yeast, a eukaryotic organism. Since it is believed that only prokaryotic organisms can utilize nitrogen from the air, this was an exciting discovery. In this small grant for exploratory research, the PIs will identify the eukaryotic genes from these nitrogen-fixing yeasts that allow growth on nitrogen-free medium, and attempt to isolate mutants that no longer grow in nitrogen-free medium. The nif gene cluster will be analyzed and compared with known diazotrophic bacteria and they will determine whether or not the genes have eukaryotic transcription signals. Identification of the known genes required for nitrogen fixation within the genome of the yeast strain will provide compelling evidence for nitrogen fixation by this eukaryotic organism. Verification that the genes known to be involved in nitrogen fixation are being expressed in the yeast strains will also provide further support for eukaryotic nitrogen fixation. If nif mutants can be isolated that no longer fix nitrogen, and if adding back the nitrogenase genes restores growth on nitrogen-free medium, it would provide unequivocal evidence of eukaryotic nitrogen fixation.The broader impacts resulting from the proposed activity include an emphasis on training of women in science. Dr. Doty will continue to lead a graduate level seminar course, Plant-Microbe Interactions in which she shares her results about the nitrogen fixing endophytes of poplar. The goal is to publish the results in a first-rate journal, and give seminars to disseminate the news widely. If successful, this research would cause a paradigm shift in current understanding of nitrogen fixation since it would be the first example of a nitrogen-fixing eukaryotic organism.

在白杨固氮内生菌的研究中，有一个深刻的发现，其中一些菌株是酵母，一种真核生物。由于人们认为只有原核生物可以利用空气中的氮，这是一个令人兴奋的发现。在这项探索性研究的小额资助中，研究人员将从这些固氮酵母中鉴定出允许在无氮培养基中生长的真核基因，并试图分离出不再在无氮培养基中生长的突变体。 nif基因簇将被分析并与已知的固氮细菌进行比较，他们将确定这些基因是否具有真核转录信号。在酵母菌株基因组内鉴定固氮所需的已知基因将为这种真核生物固氮提供令人信服的证据。证实已知参与固氮的基因在酵母菌株中表达也将为真核固氮提供进一步的支持。如果能分离出不再固氮的nif突变体，并且如果重新加入固氮酶基因能在无氮培养基上恢复生长，那么这将为真核生物固氮提供明确的证据。Doty博士将继续领导一个研究生水平的研讨会课程，植物微生物相互作用，她在其中分享了她关于白杨固氮内生菌的结果。我们的目标是在一流的期刊上发表研究结果，并举办研讨会，广泛传播这一消息。如果成功，这项研究将导致目前对固氮的理解发生范式转变，因为它将是固氮真核生物的第一个例子。