Studies On Diversity Of Endophytic Bacteria In The Nodule Of Podocarpus Imbricatus.

It is a common phenomena that there are nodules on the Podocarpus imbricatus. roots in nature. For studying the diversity of endophythic bacteria in nodule of P. imbricatus. and the diversity in different environments. We collected the P. imbricatus. nodules from different environment, such as the upland and the campestris environment. There is a Taxus at the side of P. imbricatus. about one hundred years. For studying the endophythic bacteria' s relationship between P. imbricatus. and leguminous plant. We respectively collected the nodules from the foot of P. imbricatus. and from the place where the two trees' roots join. Finally, we got the bacterial strains Ml, M2, M3, J4, M5 from the campestris environment. Got the bacterial strains M8-1, M8, M8-2", M82, M8-2', M83, M8-2, M63, M61—1 from the foot of P. imbricatus. .Got the bacterial strains J1, J2, J3 from the place where two trees' roots join. Got the bacterial strains H1 from the nodule of Taxus. We also found that these strains could invade R. pseudoacacia via root hairs, and leads to root nodule from the experimental data. We sequenced the full-length 16S rDNA sequence of representative strains J1, J2, J3, J4, M8, H1, and compared with that of type strains of all known related bacteria. We found that strains J1, J2, J3 and Hi are uncultured bacteriums, strains M8 and J4 are Bacillus. When we compared the sequence of strains J1 and J2 with strain H1, we found that the identities is 98%.We confirmed that strains J4 and M8 are Bacillus. In order to understand how could the Bacillus. invade R. pseudoacacia via root hairs, and leads to root nodule, and discussed the reciprocity of B. subitilis azotofixans and plants. We took some experiments to observe the changes of R. pseudoacacia roots after B. subitilis invading R. pseudoacacia as well as the ultrastructure of R. pseudoacacia root nodule infecting cells, we found that: B. subitilis also invades R. pseudoacaciavia root hairs, and leads to root nodule; the infection thread of which is similar to that of rhizobium, but the structures of infected cells are not exactly the same; the formation of B. subitilis' peribacteroid membrane as well as the way it penetrates cell wall is also different from that of rhizobium.In order to avoid the traditional culture which might lose some environmental bacterium, to understand the diversity of endophythic bacteria in nodule of P. imbricatus, actually. We took some methods to extracted the mixed DNA from the nodule. And then using the mixed DNA as template strand to do PCR of 16S rDNA. We can make the diversity sure by this method. Finally, In despite of the method of extracting mixed DNA was successful, we haven't found the way to make the diversity sure by the mixed DNA.