The Microbial Diversity And Growth-Promoting Rhizobacteria Of Jujube Rhizospere

The soils were sampled by three-point-sampling method from 3 years old jujube tree and 8 years old jujube tree rhizosphere in Hetian,Kashi and Aksu Prefecture,and the soil properties were detemined.Using the 454 pyrosequencing technology was used to investigate soil microbial diversity and community structure.Rhizosphere microbes were isolated through selective medium.Then quantity analysis of rhizosphere bacteria,fungi and actinomyces was conducted.Rhizosphere azotobacter,phosphobacteria,potassium-bacteria were cultivated by plate cultivation method with selective medium,and antagonistic bacteria which showed antagonistic activity against Rhizoctonia solani or Fusarium camptoceras were screened.the soil samples,with Phytophthora melonis and Fusarium oxysporum as target pathogen.We determined the biological activity of each strain,and selected the strains with higher levels to study the colonization regularity.The main results were as follows.1.The analysis of the jujube rhizosphere microbe diversity and community structure showed that the bacteria and actinomycetes diversity and richness in 8 years old jujube rhizosphere were higher than 3 years old,but the fungal diversity and richess in 8 years old jujube rhizosphere were lower than 3 years old.The dominant bacterial phyla were Proteobacteria and Actinobacteria,Actinomycetes subclass in Actinobacteria occupy the highest proportion,Ascomycota had a major advantage.2.Use of similarity clustering tree and principal coordinate analysis of samples between six microbial community structure similarity comparison,results are as follows:soil samples from the same sampling area between bacteria,actinomycetes bacteria community structure differences smaller,high similarity,while fungi community structure is smaller differences between the same soil sample age,high similarity.Affecting more than jujube-old regional site conditions affecting Xinjiang jujube rhizosphere bacterial community structure and by actinomycetes,and fungal community structure dates affected age is greater than the sampling site conditions in different regions3.Three sampling areas for comparing results of microbial communities,three regions accounted the main bacterial phyla were Proteobacteria and Actinomycetes,there are major actinomycetes subclass was Actinomycetes,Acidobacteria,Bacteroidetes,Firmicutes,and Gemmatimonadetes.Rubrobacteridae only exists in soil samples from Aksu Prefecture.Ascomycota fungi in soil samples are composed of three regions occupy a major advantage,Basidiomycota and classification is not clear a large proportion of fungi in Hetian Prefecture,balloon door bacteria exist only in soil samples Hetian region.To 3 years old and raw red jujube jujube rhizosphere microbial community structure composed of eight years in Hetian example for comparative analysis.The results showed,the bacterial and fungal communities were affected by root exusate,in general,3 years old jujube rhizosphere soil bacteria occupy the main categories in proportion to occupy less than eight years,the proportion of students in the rhizosphere soil dates,and fungal communities showed the opposite trend.4.Redundancy analysis(RDA)was performed to study the effect of soil properties on abundant phyla.The results showed the results showed significant correlation between soil properties and abundant bacterial phyla,and relative abundance of Acidobacteria were positively correlated with the soil available P and pH.The relative abundance of Nitrospira,Gemmatimonadetes,Chiorobi and unclassified-Bacteria was positively correlated with moisture and organic matter,and negatively correlated with available K and available N5.By using selective medium and screened various microbial count analysis,the results showed that the number of changes in bacterial three sampling areas are showing the same trend,jujube tree roots up to the occasion in Hetian bacteria,followed by the Kashi region dates roots inter bacteria,at least the number of bacteria in rhizosphere Aksu Prefecture.Number of rhizosphere fungi and actinomycetes also showing a similar variation.However,the same area between different sampling microbial lives does not change regularly.Rhizosphere nitrogen-fixing bacteria,solubilizing bacteria,silicate bacteria and antagonistic bacteria Hetian,Kashi,Aksu Prefecture rhizosphere a diminishing number,in addition to understanding inorganic phosphorus bacteria,other bacteria in three functions 8-year-old roots of interpersonal dates number greater than 3 years old jujube tree roots occasion.6.The results of nitrogenase activity measurement of azotobacter showed that the activities of A-N-7?B-N-6?B-N-14?C-N-3?D-N-10?E-N-7 and F-N-9 were the highest,and their activities were 32?15mg/g?33?34 mg/g?32.27 mg/g?28.30 mg/g ? 22.77 mg/g?27.34 mg/g ? 20.27 mg/g,respectively.The strains A-WP-6?A-WP-1?B-WP-1,B-WP-2?B-WP-14?C-WP-13?C-WP-10?D-WP-13 and D-WP-8 had higher inorganic phosphate solubilizing capacity.The Potassium-releasing activities of A-K-24?B-K-15?B-K-2,C-K-6?C-K-9?D-K-18 and F-K-17 were higher than that of others.The strains 3-7?HZ-4?HZ-5?DZ-5 showed stronger antagonistic activity against Rhizoctonia solani or Fusarium camptoceras.7.Using RifR and SpeR strains to study the colonization ability of 15 strains of rhizosphere bacteria which have higher biological activity.The results show that,12 strains could be colonization in jujube rhizosphere.8.The composite results of thalli shape and bacterial colony,physiology and biochemistry indicator analysis,16S rDNA analytic result showed that,DZ-5 belonged to Bacillus subtilus,HZ-5 belonged to Paenibacillus polymyxa,3-7 belonged to Pseudomonas aurantiaca,A-K-24 belonged to Pseudomonas chlororaphis,A-K-23 belonged to Serratia marcescens,A-WP-6 belonged to Acinetobacter calcoaceticus,A-WP-1 belonged to Bacillus megaterium,A-N-7 belonged to Serratia marcescens,A-N-26 belonged to Pantoea agglomerans.