[Diversity of fe-hydrogenase microbe in Guizhou red paddy soil during flooding incubation].

Objective: The diversity of Fe-hydrogenase based on Fe-hydrogenase gene of Clostridium was studied for exploring the biochemical mechanism of soil microbial hydrogen production and revealing the Fe-hydrogenase microbial community structure changes during the paddy soil flooding incubation.
Methods: We used denatured gradient gel electrophoresis and real-time quantitative PCR to achieve the goal.
Results: The band number of Fe-hydrogenase denatured gradient gel electrophoresis fingerprints indicated Fe-hydrogenase microbes structure varied significantly during the completely flooding incubation. The Principal Component Analysis (PCA) showed the highly similar communities of Fe-hydrogenase microbial was divided into three groups: 1 d and 20 d, the 5 d, 30 d and 40 d. With the growth of the flooding incubation time Fe-hydrogenase microbial community structure became relatively stable and convergence. Alpha diversity index analysis found that the richness index (R), Shannon-Weaver index (H'), Simpson index (D(S)) numerical values of 1 d and 10 d were lower compared with other points, indicated the two time points of low Fe-hydrogenase diversity, simple Fe-hydrogenase microbial community structure and successive variation of community structure during the whole flooding incubation. After sequencing 15 Fe-hydrogenase preponderant bands ( labeled by G1 - G15), the phylogenetic tree of Fe-hydrogenase showed that the preponderant bands all had high similarity with the Clostridium Fe-hydrogenase in earlier flooding incubation stage and non-Clostridium Fe-hydrogenase in the later stage. Real-time quantitative PCR results demonstrated that the Fe-hydrogenase gene copy number was 10(6) level.
Conclusion: In the research we found 4 kinds of Clostridium Fe-hydrogenases and three kinds of non-Clostridium Fe-hydrogenases, the corresponding Fe-hydrogenase microbial community structure had successively significant variation in the early incubation stage and tend to be relatively stable and convergence in the late stage.