Bacterial Diversity Of Soil Samples From The Yellow River Delta And Isolation, Identification And Characterization Of Halophilic Bacteria

Our government has payed attention to the development and protection of the Yellow River Delta,which has a unique ecological environment. However, the area of the salty soil is getting larger andlarger. Therefore, it is important to study the soil bacterial diversity and the microbial resources of theYellow River Delta National Reserve Area (YRDNRA).By culture-independent approach and culture-dependent approach, we have constructed16S rDNAcloning libraries to analyse the bacterial diversity of the salty soil from YRDNRA, in which there is nohuman intervening and the soil was not transformed artificially. To supplement the microbial resourcesinformation, some strains of the halophilic bacteria were also isolated and identified from the salty soilof the Yellow River Delta.In June2010, we sampled the soil from non-human-intervention area of YRDNRA. Bothculture-independent approach and culture-dependent approach were used to order to analyse thebacterial diversity. A16S rDNA library was constructed by culture-independent approach whichincluded86clones. With a threshold of97%sequence similarity, these clones formed to55OTUs andbelonged to8different phyla including Proteobacteria, Planctomycetes, Firmicutes, Chloroflexi,Bacteroidetes, Actinobacteria, Verrucomicrobia and Deferribacteres.44culturable clones were obtainedby culture-dependent approach. These clones belonged to3different phyla including Proteobacteria,Firmicutes and Actinobacteria. Results showed that more information of bacterial community anddiversity could be obtained by culture-independent approach than by culture-dependent approach.In addition,3strains named BJGMM-B24, BJGMM-B45and BJGMM-B49were isolated whichwere aerobic, gram-negative and moderately halophilic bacteria. They can stand10-200g/l NaCl, andsome antibiotics in the certain concentrations. Their optimal growth conditions is100g/l NaCl,30℃, pH7.2. Identification results which were conducted by Institute of Microbiology, Chinese Academy ofSciences showed that BJGMM-B24, BJGMM-B45and BJGMM-B49belonged to Halomonas cupida,Halomonas sp. and Halomonas salifodinae, separately. BJGMM-B45may be a novel species.In June2011,2soil samples (S1and S3) from non-human-intervention area and1sample (S4) fromsurrounding artificially transformed area of YRDNRA were sampled. Three16S rDNA libraries (L1, L3and L4) were constructed by each soil sample. With the threshold of97%sequence similarity,175clones of16S rDNA library L1formed to98OTUs and belonged to13different phyla includingProteobacteria, Planctomycetes, Verrucomicrobia, Firmicutes, Chloroflexi, Bacteroidetes,Actinobacteria, Cyanobacteria, Chlorobi, Deinococcus-Thermus, Acidobacteria, Phototrophicbacterium and Eukaryota.263clones of16S rDNA library L3formed to161OTUs and belonged to13different phyla including Proteobacteria, Planctomycetes, Verrucomicrobia, Firmicutes, Chloroflexi,Bacteroidetes, Actinobacteria, Cyanobacteria, Acidobacteria, Eukaryota, Nitrospirae, Deferribacteresand Armatimonadetes.188clones of16S rDNA library L4formed to161OTUs and belonged to7different phyla including Proteobacteria, Verrucomicrobia, Chloroflexi, Bacteroidetes, Actinobacteria, Acidobacteria and Eukaryota. Results showed that bacterial diversity of the salty soil of the YellowRiver Delta were abundant. Rarefaction analysis also showed that the abundance of the bacterialdiversity of that area was more than expected.