This research investigates the novel hypothesis that B. japonicum, the nodulating nitrogen-fixing symbiont for soybean, may suppress plant disease resistance. B. japonicum produces gibberellin (GA), which typically serves as an endogenous plant growth promoting hormone, but also suppresses plant responses to microbial infection. The production of GA might generally inhibit the plant defense response to microbial infection, such that plants nodulated by the usual GA+ producing B. japonicum would have reduced resistance to microbial disease, forming the basis of this project. This work explores if soybean plants nodulated by the knock-out GA strain are more resistant to sudden death syndrome and root rot, and infestation by soybean cyst nematodes, compared to plants nodulated by GA+ B. japonicum. Increased resistance to disease and/or nematode infestation, with no loss of nitrogen-fixation, would offer an obvious advantage.

Key Benefactors:
farmers, agronomists, Extension agents