Study On The Diversity Of Uncultured Bacteria In Different Types Saline-alkali Soil From Dunhuang Region

In order to understand the bacterial diversity and the relationship between bacterial community composition and environmental factors which was obtained in different types saline-alkali soil from Dunhuang region.In the study,by using the methods of molecular ecology included Illumina Hi Seq 2500 high-throughput sequencing system and constructed bacterial 16 S r RNA gene clone libraries.The results of this study were:(1)The high-throughput sequencing analysis provided information that the number of effective sequences which was divided 4997 OTUs.Bacterial phylum mainly included 17 bacterial phyla(Firmicutes,Actinobacteria,Proteobacteria,Deinococcus-Thermus,Bacteroidetes,Gemmatimonadetes,Chloroflexi,Acidobacteria,Planctomycetes,Fibrobacteres etc.)and unknown groups.The medthod of 16 S r RNA gene clone libraries found that six phyla,belong to Firmicutes,Actinobacteria,Bacteroidetes,Planctomycetes,Acidobacteria and Proteobacteria.The dominant phylum was Firmicutes in all soil samples.(2)The method of high-throughput sequencing analysis found 266 bacterial genera included that other and unknown.The dominant species was Enterococcus in three types soil samples.The method of constructed bacterial 16 S r RNA gene clone libraries found the dominant families was Enterococcaceae in gobi and oasis soils,but the dominant families was Pseudomonadaceae in transition zone soil.(3)The high-throughput sequencing and 16 S r RNA gene clone libraries diversity index analysis showed that the highest bacterial diversity and abundance from oasis soils.The lowest bacterial diversity and abundance from gobi soils.(4)Environmental factors(p H,rapidly-available potassium,available nitrogen,effective phosphorus and soil conductivity)have obvious influence on bacterial community composition.The influence of soil p H value and conductivity has significant effects on bacterial community.Acidobacteria,Candidate_division_TM7 and Chlorobi were negatively correlated with the soil p H.Acidobacteria,Actinobacteria,Chloroflexi,Gemmatimonadetes,Candidate_division_TM7,Chlorobi and Cyanobacteria were negatively correlated with the soil electrical conductivity.Firmicutes was positively correlated with the soil electrical conductivity.(5)Firmicutes are widely distributed in three kinds of soil,but the highest abundance in gobi soil samples.In particular with the increase of soil electrical conductivity,Firmicutes abundance increase.(6)The high-throughput sequencing analysis the sequence belong to 17 bacterial phyla and unknown groups.Clone library only found 6 bacterial phyla in soil samples.These 6 bacterial phyla in high-throughput sequencing results has also been found.Through the research can be found in dunhuang area contained a lot of unknown bacteria groups,there were a large quantity of bacteria groups.