Characteristics Of Denitrifying Microbial Community Structure And Niche Differentiation In Rhizosphere Soil Of Dominant Plants In Ebinur Lake Wetland

As the most representative temperate arid region wetland ecosystem,Ebinur Lake wetland ecosystem plays a very important role in regulating the climate in northern Xinjiang and maintaining ecological balance.In this study,by constructing the nirS gene library of three different plant rhizosphere and non rhizosphere denitrifying microorganisms in the wetland of Ebinur Lake,and using the method of fluorescence quantitative PCR,combined with the characteristics of different rhizosphere and non rhizosphere environment of different plants,the difference of environmental heterogeneity between the denitrifying microorganisms in the saline alkali soil of Ebinur Lake wetland was studied,and the rhizosphere of the plant was revealed.The characteristics of denitrifying microbial community structure,diversity and quantity niche in non rhizosphere.In this paper,soil environment characteristics were measured to understand the rhizosphere and non rhizosphere soil conditions of different plants.According to the measured data of soil physical and chemical factors,the pH values of rhizosphere and non rhizosphere of three plants were all above 8,all of them were alkaline soil.Water content:Phragmites australis>Salicornia europaea>Halocnemum strobilaceum;EC is salt content.Halocnemum strobilaceum content is the highest in rhizosphere soil of salty tree,and there is a significant difference from non rhizosphere,which is the lowest in non rhizosphere soil of Salicornia europaea.The general expression is that the rhizosphere is higher than the non rhizosphere.The range of organic matter in rhizosphere and non rhizosphere soil is 3.29-5.77 g/kg,and the content of organic matter in the rhizosphere soil of Halocnemum strobilaceum is higher,and the content of organic matter in Salicornia europaea is lower.The total nitrogen content in rhizosphere and non rhizosphere soil is 0.47-0.62g/kg.The contents of TN and NH₄⁺-N were the highest in rhizosphere soil of Phragmites australis.The content of AN was the highest in the non rhizosphere soil of Phragmites australis,and the content of nitrate nitrogen in rhizosphere soil was highest.The contents of TP and TK in rhizosphere and non rhizosphere were higher than those in non rhizosphere.In addition to AK of Phragmites australis and AP of Salicornia,AP and AK both showed greater rhizosphere than non rhizosphere.The diversity analysis of the clone library showed that the diversity of denitrifying microbial community diversity existed in the rhizosphere and non rhizosphere soils of different plants.The diversity index of the nirS Library in the Halocnemum strobilaceum node intersoil soil,the Chao1 index,the ACE index and the Shannon-Wiener index library were lower than those of the salt node.The other two libraries?Phragmites australis and Salicornia europaea?were rhizosphere diversity index larger than non rhizosphere.Compared to the diversity of the rhizosphere of the three plants,Phragmites australis>Salicornia europaea>Halocnemum strobilaceum sawwood and the denitrification diversity of the non rhizosphere of the three plants are known to be known as Salicornia europaea>Halocnemum strobilaceum>Phragmites australis.The rhizosphere diversity of Phragmites australis was highest in rhizosphere and non rhizosphere of all plants.The diversity of denitrifying microbial communities in Phragmites australis non rhizosphere was the lowest.The results of phylogenetic tree show that the common denitrifying microorganisms in the rhizosphere and non rhizosphere of the three plants are Halomonas and Pseudomonas,and some uncultivated denitrifying microorganisms from the estuarine sediments.The genus Salmonella is a dominant population in the rhizosphere of Salvia.Pseudomonas is a dominant population in the non rhizosphere soil of Phragmites australis.A small number of Azotobacter and??-Proteobacteria?were found in the rhizosphere and non rhizosphere of Salicornia commune and rhizosphere of Phragmites australis and the non rhizosphere soil of Salicornia.A small amount of denitrifying microbes with Vibrio azovibrio are also found in the Halocnemum strobilaceum and Phragmites australis rhizosphere,and Sulfuricaulis exists in the salt node,Phragmites australis rhizosphere and non rhizosphere of Salicornia.In the rhizosphere of Phragmites australis,the non rhizosphere of Halocnemum strobilaceum,the rhizosphere of Salicornia palustris,and the non rhizosphere of Salicornia palustris,the denitrifying microorganism is mainly?-Proteobacteria,in which most of the sequences in the sample are not culturable and have not been identified.The results of qPCR showed that the highest abundance of nirS was in non-rhizosphere soil of Salicornia europaea?2.35×10⁶ copies/g?,and the lowest abundance of nirS was in non-rhizosphere soil of Halocnemum strobilaceum.In the Halocnemum strobilaceum of root rhizosphere and non-rhizosphere soil in nirS abundance:Mufeigen rhizosphere rhizosphere than Halocnemum and there are significant differences.There was no significant difference in rhizosphere and non rhizosphere abundance between Phragmites communis and Salicornia palustris.The abundance of nirS in rhizosphere of rhizosphere and non-rhizosphere of Salicornia palustris:rhizosphere is greater than that of non-rhizosphere.The abundance of denitrifying microorganisms in rhizosphere of three plants was S>R>H:compared with three non rhizosphere,the abundance of denitrifying microorganisms was RN>SN>HN.RDA indicates that pH,EC,OM,TN and NH₄⁺-N were related to the diversity and abundance of Denitrifying microorganism.Conclusions:The soil of the Ebinur Lake wetland is saline alkali soil with low water content and poor soil nutrition.Except Halocnemum strobilaceum Festival diversity as root than the non rhizosphere,Phragmites australis and Salicornia europaea in rhizosphere were higher than those in the non rhizosphere.The common denitrifying microbes in the rhizosphere and non rhizosphere of the three plants are Halomonas and Pseudomonas,and some uncultivated denitrifying microorganisms from the estuarine sediments.The abundance of nirS in the rhizosphere of Phragmites australis is the highest.Therefore,the diversity and community structure and abundance of rhizosphere and non rhizosphere of different plant rhizosphere and non rhizosphere and each plant are different.Electrical conductivity,organic matter,ammonium nitrogen and pH may affect the community structure and abundance of denitrifying microorganisms.