In the past year, we discovered that B. japonicum makes GA most strongly during the flowering stage of soybean. Given that our previous studies were largely focused on earlier stages, we have verified that the ga-­- knock-­-out strain is still able to fix nitrogen and enable soybean plant growth in an equivalent manner to the parental GA+ B. japonicum through the flowering stage. In addition, we have carried out experiments for each of the three project objectives outlined above, using plants both just before and in the flowering stage. Our data for SDS indicates that soybean plants nodulated with the ga-­- knock-­-out strain are significantly more resistant to SDS than those nodulated with the parental GA+ B. japonicum if infected before, but not during, the flowering stage. We are currently repeating these experiments to verify and further investigate the effect of plant developmental stage.
Nevertheless, given that the tested diseases target seedlings, we remain optimistic that this approach may be of agricultural utility.