Abstract:

Soybean originated in China and is an important oil crop. The soybean-rhizobium symbiosis provides a rich nitrogen source for soybeans. Rhizobium type Ⅲ effector is one of the key signal molecules that affect symbiotic nodulation. The nodulation identification of HH103ΩNopAA and HH103ΩNopD shows that the two mutants have different host compatibility for Suinong 14 and ZYD00006, and a double mutant of HH103ΩNopAAΩNopD was constructed by tri-parental mating method on the basis of HH103ΩNopAA. Suinong 14 and wild soybean ZYD00006 were used to identify the nodules of the mutants. The nodule number and nodule dry weight of HH103ΩNopAAΩNopD were not significantly different from those of HH103ΩNopAA. Then, we used 100 soybean resources collected in the previous stage to identify the nodulation, and analyzed the nodulation characteristics of soybean varieties with NopAA and NopD mutations under different genetic backgrounds. The number of nodules in most varieties was significantly reduced, and the number of nodules in some varieties was inoculated with single mutations. There are significant differences between the mutant and the double mutant. This study provides new ideas for the subsequent analysis of the symbiotic signal transduction between NopAA and NopD and the compatibility of rhizobium with soybean varieties. At the same time, based on the differences in genotypes, soybean varieties that have higher compatibility with different rhizobia can be screened to provide support for the further cultivation of soybean varieties with high nodulation and high nitrogen fixation.

Key words: soybean, rhizobium, type Ⅲ effector, NopAA, NopD, symbiosis