Rhizosphere Soil Microbial Diversity In Elaeagnus Angustifolia And Isolation And Identification Of Symbiotic Nitrogen Fixing Actinomycetes In Rhizosphere And Nodules

Elaeagnus angustifolia is a branch of the Elaegnaceae Lnn,and it is also known as Yunliu,Guangxi,Oilixiang.It mainly distributed in the north and northwest regions of China.Elaeagnus angustifolia is a versatile plant.The branches,leaves,flowers and fruit of Elaeagnus angustifolia are valuable in food processing,medicine refining and feed development etc..At the same time,Elaeagnus angustifolia also has the excellent characteristics of drought and salt resistance,known as sandy,saline alkali land"baoshu".It has been listed as an important planting Elaeagnus species in arid and drought areas.There may be nitrogen fixation of Elaeagnus angustifolia root microorganism,these microorganisms could improve soil fertility,ameliorate soil nutrient composition and promote root development and improve the ability of plant disease resistance.Nowadays,due to man-made soil degradation and extreme climatic environment,crop growth and development are limited.Therefore,a solution is urgently needed to solve this problem.The test materials are rhizosphere soil,root of Elaeagnus angustifolia saline-alkali soil of Zhaodong,Heilongjiang province.This experiment researches the bacterial community structure in rhizosphere soil by the Pyrosequencing technology,analyzes the relationship between soil microorganisms and environment through determining the factors of soil environment and further studies theconnection of the Elaeagnus angustifolia seedlings and the under salt stress snitrogen-fixation organism through back connection test.Isolation and identification of a strain of nitrogen fixation of salt tolerant Actinomycetes strain as the starting strains,As to the host plant of Elaeagnus angustifolia inoculation experiment,further study the relationship between nitrogen fixing microorganisms and Elaeagnus angustifolia seedlings under salt stress.Through the high through put sequencing technique,we found that the number of OTU in rhizosphere soil microorganisms was 2221,2026 and 2186,respectively.The total number of OTU was 1755,and the number of unique OTU was 103,76 and 23respectively.It can be seen that there are some similarities between the tested soil samples,but there are also differences.From the rhizosphere soil of three years were detected in all 13 bacterial genera,respectively mycetozoan Proteobacteria,Actinobacteria,Acidobacteria,Bacteroides,Chloroflexi,Gemmatimonadetes,Verrucomicrobium,Nitrospirae,Cyancbacteria,Saccharibacteria and Planctomycetes and other bacteria,three soil microbial abundance in Elaeagnus angustifolia rhizosphere highest is mainly Proteobacteria and Actinobacteria.The use of PCR gene were screened 21 strains of nitrogen fixing actinomycetes.Na Cl tolerance studies showed that 10 strains could still grow well when Na Cl concentration reached 6%,and the 10 strains belonged to Streptomyces by 16S and r RNA sequencing.The strain 14-1 with the highest salinity resistance was used as the starting strain for identification of bacteria,and finally the strain 14-1 was identified as Microflavus Streptomyces.The separation and purification of high salt tolerant nitrogen fixing function of Streptomyces 14-1 as starting strains were reinoculated test in Elaeagnus angustifolia as experimental materials were studied on 14-1 angustifolia salt tolerance mechanism,to study its effect on the growth of Elaeagnus angustifolia seedlings,the following data:14-1 salt and CK plus salt were plant height,ground and underground dry weight were increased by 10.15%,2.79%,12.77%,the conductivity decreased 9.97%,salt content decreased 12.17%,the content of MDA decreased 22.12%,the content of SOD increased by 20.94%,the content of Pro increased by 50.8%,the content of SOD increased by2.98%,the content of CAT increased by 35.28%,POD 6.68%,Na+concentration decreased by 7.16%,K⁺and Ca²⁺respectively increased by 29.3%and 7.16%,the ratio of Na⁺/Ca²⁺increased by 839%,the ratio of Na⁺/K⁺increased by 675%,the ratio of Na⁺/Mg²⁺increased by 2800%,invertase increased by 1.94%The urinary enzyme increased by 22.63%,catalase increased by 11.76%,phosphatase increased by 13.6%.Through the connection of strain 14-1 significantly increased the salt tolerance of Elaeagnus angustifolia,reduce lipid peroxidation,which indicated that the expression of14-1 might be related to the regulation of Elaeagnus angustifolia strains of salt tolerance related genes,but the specific situation needs further research.