| Bradymonadales is a predatory bacterial group isolated from sediments.As there are difficulties in its isolations,the study on the detection method of this group is of great significance for determining its distribution in the environment and analyzing the correlation with other groups.In this study,certain oligonucleotide probes were designed for the group of Bradvmonadales,and their rigor and coverage were verified by pure bacteria experiments.A pair of fluorescent quantitative PCR primers were designed and synthesized based on the probe sequence.The experimental verification found that the designed oligonucleotide probe can hybridize with all the currently cultured Bradymonadales groups,and at the same time,the hybridize result with the non-target group selected in this experiment is negative.The sediment samples of 5 salt ponds with different salinity gradients at Wendeng Saltern and 6 salt lakes in Yuncheng Salt Lake were picked as the research objects.The 16S rRNA gene amplicon sequences,qPCR and fluorescence in situ hybridization method were used to analyzed the abundance of Bradymonadales.Through 16S rRNA gene high-throughput sequencing,the presence of Bradymonadales was detected in all sediment samples of salt lakes and saltern,and a total of 91 OTUs belonging to Bradymonadales were detected.There were 49 unique OTUs in Wendeng Saltern sediments and 15 unique OTUs in Yuncheng Salt Lake sediments.The average relative abundance of Bradymonadales is 0.81%and 0.16%in Wendeng Saltern sediments and Yuncheng Salt Lake sediments.The relative abundance of 16S rRNA gene of Bradymonadales was detected to be 0.07%?8.30%by qPCR method.Through fluorescence in situ hybridization,the target cell group of Bradymonadales was observed in the sediment samples of Wendeng Saltern.Due to the cell number of successful hybridizations of Bradymonadales was not much,there was no clear count of Bradymonadales ordersAt the same time,this study analyzed the bacterial community structure and physical and chemical factors of Wendeng Saltern and Yuncheng Salt Lake.Through analysis,it was found that the diversity of bacterial community in sediments was higher than that in water samples.Proteobacteria and Bacteroidetes were main dominant phyla in all samples,while Euiyachaeota,Halanaerobiaeota,Verrucomicrobia and Actinobacteria have relatively high abundance in some salt ponds.Various physical and chemical factors such as salinity and ion concentration of water samples and sediments have important effects on community structure.By constructing molecular ecological network analysis of sediments and water samples,the network structures in sediments were obviously more complicated than that in water samples.The key nodes in the networks were mainly distributed in Proteobacteria,Bacteroidetes,Actinobacteria and FirmicutesIn this paper,we conducted classification studies on two potential novel strains.The taxonomic status of strains 1KV19T and KN1008T were determined through polyphasic taxonomy studies including phylogenetics,genomics,phenotypic characteristics,and chemical taxonomy.Strain 1KV19T represents a new species in the genus Lutibacter.It is recommended to name it Lutibacter citreus sp.nov.And the model strain is 1KV19T(=KCTC 62595T=MCCC 1H00307T)Strain KN1008T represents a new species in the genus Gramella,and it is recommended to be named Gramella litoralis sp.nov.The model strain is KN1008T(=KCTC 62961T?MCCC 1H00279T)... |
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