Progress 10/01/06 to 10/01/07
Outputs
We isolated three yeast strains from within poplar trees that seem to be able to fix atmospheric nitrogen. We have conducted 15N2 incorporation experiments three times with the result that the endophytic yeast can incorporate the 15N label while control yeast cannot. This is strong evidence of nitrogen fixation. We have done a series of growth experiments that demonstrate that the endophytic yeast can grow in medium lacking nitrate or ammonium for extended periods of time, even when antibiotics are present. Using universal primers, we amplified a portion of the nifH gene that encodes one of the subunits of the nitrogenase enzyme essential for nitrogen fixation. We did total nitrogen experiments and found that the endophytic yeast have an increased quantity of nitrogen in the cells after growth in nitrogen-free medium while control strains have a decreased level. The best explanation for these data is that the poplar yeast strains are fixing atmospheric nitrogen. The
Department of Energy accepted our nomination of one of the strains for genomic sequencing. We have been preparing DNA for the DOE Joint Genome Institute, and hope to obtain more of the nitrogenase gene sequences soon. We have also initiated mutagenesis experiments to isolate the genes that allow the yeast to fix nitrogen. Graduate student, Gang Xin, has been fully supported and Research Scientist Azra Vajzovic has been partially supported by this grant for the past year as they learned the microbiology and molecular biology skills necessary for this project. Mr. Xin presented his data at the local meeting of the American Society of Microbiologists, and Ms. Vajzovic presented at the symposium for the Consortium of Plant Biotechnology Research. I presented our research at the conference for the International Society of Molecular Plant-Microbe Interactions in Sorrento, Italy this summer. We also taught graduate students about our work in my class, CFR 522 Plant-Microbe Interactions in
spring quarter.
Impacts
If it is unequivally demonstrated that these endophytic yeast strains from poplar are able to fix atmospheric nitrogen, it would be a paradigm shift in our understanding of nitrogen fixation. It is believed that only prokaryotic organisms can fix ntrogen. If these yeast strains are diazotrophic, it would be the first case of eukaryotic nitrogen fixation.
Publications
- No publications reported this period
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Progress 09/01/06 to 08/31/07
Outputs
OUTPUTS: We isolated three yeast strains from within poplar trees that seem to be able to fix atmospheric nitrogen. We have conducted 15N2 incorporation experiments three times with the result that the endophytic yeast can incorporate the 15N label while control yeast cannot. This is strong evidence of nitrogen fixation. We have done a series of growth experiments that demonstrate that the endophytic yeast can grow in medium lacking nitrate or ammonium for extended periods of time, even when antibiotics are present. Using universal primers, we amplified a portion of the nifH gene that encodes one of the subunits of the nitrogenase enzyme essential for nitrogen fixation. We did total nitrogen experiments and found that the endophytic yeast have an increased quantity of nitrogen in the cells after growth in nitrogen-free medium while control strains have a decreased level. The best explanation for these data is that the poplar yeast strains are fixing atmospheric nitrogen. The Department of Energy accepted our nomination of one of the strains for genomic sequencing. We have been preparing DNA for the DOE Joint Genome Institute, and hope to obtain more of the nitrogenase gene sequences soon. We have also initiated mutagenesis experiments to isolate the genes that allow the yeast to fix nitrogen. Graduate student, Gang Xin, has been fully supported and Research Scientist Azra Vajzovic has been partially supported by this grant for the past year as they learned the microbiology and molecular biology skills necessary for this project. Mr. Xin presented his data at the local meeting of the American Society of Microbiologists, and Ms. Vajzovic presented at the symposium for the Consortium of Plant Biotechnology Research. I presented our research at the conference for the International Society of Molecular Plant-Microbe Interactions in Sorrento, Italy this summer. We also taught graduate students about our work in my class, CFR 522 Plant-Microbe Interactions in spring quarter. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
If it is unequivally demonstrated that these endophytic yeast strains from poplar are able to fix atmospheric nitrogen, it would be a paradigm shift in our understanding of nitrogen fixation. It is believed that only prokaryotic organisms can fix ntrogen. If these yeast strains are diazotrophic, it would be the first case of eukaryotic nitrogen fixation.
Publications
- No publications reported this period
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