| 1. Diversity of endophytic bacteria community structure of riceThe diversity of endophytic bacteria in the wild rice, hybrid rice and cultivated rice was studied. Twenty-nine endophytic bacteria were isolated from the rice and identified by Microbial Identification System (MIS). Among the bacteria, 11 species were classified with Similarity Index more than 0.6, that belonged to 5 genuses such as Bacillus, Pseudomonas, Stenotrophomonas, Microbacterium and Acinetobacter. The genus Bacillus was the abundance one in the endophytic bacteria community. The principal components analysis was introduced into grouping the characteristics of bacteria community structure by using endophytic bacteria as samples and cultivar as variables. The results showed that the 11 species could be classified into 3 groups correlated with the rice cultivars. Moreover, the distribution of endophytic bacteria were found to have relationship with the part of rice by 0-1 cluster analysis2. Diversity of endophytic bacteria and rhizosphere bacteria on riceThe relationship between the diversity of endophytic bacteria and rhizosphere bacteria of rice cultivar was investigated. In total, 18 species of bacteria were collected from both of the plant and the rhizosphere. Among which, the endophytic bacteria were identified and classified into 13 species and rhizosphere bacteria belonged to 10 species. According to the diversity indexes of Simpson index, Shannon-Wiener index, Brillouin index, Pielou index and McIntosh index, the community diversity of endophytic bacteria was found to be greater than that of rhizosphere bacteria. The results of statistics analysis showed that there was canonical correlation between the community structures of endophytic bacteria and rhizosphere bacteria. They had 4 correlational coefficients and reached the greatest correlations, while the correlational coefficient was 0.9447. The relationships were positively correlated between the amount of bacteria and the grain number per spike, seed setting rate, 1000-grain weight and plant production, respectively. However, the bacteria content performed negative correlation with the effective spikes.3. Microbial community diversity of endophytic bacteria of riceThe microbial community diversity of endophytic bacteria of different rice cultivars was explored by using improved method of phospholipid fatty acid biomarkers detection (PLFA). The PLFAs of endophytic microbial of rice were abundant and different. Twenty-seven PLFAs biomarkers were detected, among which 8 PLFAs distributed completely and 19 PLFAs distributed incompletely in the plant of rice. The PLFAs were collected into 2 groups by cluster analysis. The structure of PLFAs of endophytic bacteria in different rice cultivars were discovered to be characteristic by Non-linear mapped analysis.4. Microbial community diversity of rhizosphere bacteria of riceUsing phospholipid fatty acid biomarkers detection, the genetic relationship between the rhizosphere microbial community structure and the rice variety was studied. The rhizosphere microbial communities of rice varieties were sampled from 7 rice varieties,e.g.â…¡you 797,â…¡you HK05,â…¡you 355,â…¡you 455, xinan youzhi 5, jinsheng youzhi 5, tian youzhi 5, with the same cultivating conditions in the experimental plot. The PLFAs was detected by MIDI to get the microbial community diversity. The quantities of PLFAs were clustered to observe the characteristics of rhizosphere microbial community in the rice varieties. The results showed that 38 PLFAs biomarkers were detected out, in which there were 23 PLFAs completely distributed and 15 PLFAs incompletely distributed in the rhizosphere soils of 7 rice varieties respectively. The quantities of PLFAs related to bacteria were higher than either that to fungi or that to actinomycetes. The results also revealed that the roots'microbial community structure represented by PLFAs was closely related to the variety biology, in which the relationship between the PLFA and the effective ear was positive, so did the production, whereas the relationship between the PLFA and the plant height was negatively correlated. Simultaneously, the cluster analysis displayed that the PLFAs were concerned with the rice heredity characteristic. It was concluded that the microbial community based on PLFAs in the rice rhizosphere soil was rich, which sensitively reflected the relation between the PLFAs and the biological and hereditable characteristics of the rice variety.
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