DECREASING FERTILIZER USE BY OPTIMIZING PLANT-MICROBE INTERACTIONS FOR SUSTAINABLE SUPPLY OF NITROGEN AND PHOSPHOROUS FOR BIOENERGY CROPS
Rattanah Mahal1, Marcus Schicklberger2.
1University of California, Berkeley, Berkeley, CA, 2Lawrence Berkley National Laboratory, Berkeley, CA.
The elements nitrogen (N) and phosphorus (P) are essential elements for the growth and survival of plants. Yet plants are limited in their ability to fix elemental N from the atmosphere, as well as hydrolyze organic and inorganic phosphorous from insoluble compounds. To compensate for this shortcoming, plants form a mutualistic relationship with bacteria to obtain usable nitrogen and phosphate. Although the majority of plants that form nitrogen-fixing root nodules are in the legume family, new species of N2-fixing bacteria have been discovered in association with non-nodulating crops. The goal of this research lies in the identification of beneficial bacteria capable of fixing nitrogen and solubilizing phosphate. In this study, high-throughput isolation (HTI) was used to identify N-fixing and/or P-solubilizing bacteria from tobacco (Nicotiana tabacum). Overall, 5 different phylogenetic orders were identified: Enterobacteriales, Bacillales, Actinomycetales, Rhizobiales, and Sphingobacteriales. The strain Kosakonia Oryzae ola 51 from the order Enterobacteriales, in particular, was identified as a nitrogen fixer by amplifying the nifH gene; those results were then confirmed by acetylene reduction assay. Ultimately, the goal of this research is to decrease fertilizer dependency by engineering plants to attract diazotrophic bacteria.