The Effects of Cadmium Contamination on Soil Bacterial Structure and Diversity in Rhizosphere Soils of Broccoli in Coastal Reclamation Area
In order to study the effects of cadmium contamination on soil bacterial structure and diversity in rhizosphere soils of broccoli in coastal reclamation area,and to find out the cadmium-resistant bacterial which were beneficial to the remediation of cadmium contamination,high throughput sequencing method was used to analyze the effects of cadmium stress on bacterial community and diversity in rhizosphere soils of broccoli in coastal reclamation areas of Taizhou estuary,Zhejiang Province.The concentrations of cadmium were set at 0,3.5,or 60 mg·kg-1,respectively,and were marked as Cd0,Cd3.5,Cd60,correspondingly.The results showed that cadmium stress could cause changes in both bacterial diversity and community structure.There were 35 phyla,97 classes,205 orders,315 families,and 506 genera in the rhizosphere soil of broccoli in this studied areas under different gradients of cadmium contamination.Low cadmium stress might raise the Chao1 index and Shannon index of soil bacterial community and high cadmium stress might reduce the Chao1 index and Shannon index of soil bacterial community.With the increase of Cd stress,the relative abundance of Actinobacteri and Planctornyces in the soils of broccoli showed a downward trend all the time,while the relative abundance of Bacteroidetes and Gemmatimonadetes are on the increase all the time.The relative abundance of soil Proteobacteria and Patescibacteria decreased first and then increased.The relative abundances of Acidobacteria,Rokubacteria,Errucomicrobia,Nitrospirae and Firmicutes in soil are increased first and then decreased.Proteobacteria,Bacteroidetes,Patescibacteria and Gemmatimonadetes are the dominant groups in high Cd contamination.With the increase of Cd stress,the relative abundance of Pseudarthrobacter,Muciaginibacter and Rhodopseudomonas in the rhizosphere soil of broccoli showed a downward trend all the time,while the relative abundance of Flavobacterium is on the increase all the time.The relative abundance of soil Rhodanobacter decreased first and then increased.The relative abundances of Sphingomonas in soil were increased first and then decreased.This indicated that low cadmium stress might stimulate the growth and production of cadmium-sensitive bacteria,which made the community structure more complex and diverse.High concentration of cadmium significantly inhibited bacteria,resulting in the extinction of some species and the decrease of diversity.High cadmium contamination could induce cadmium-resistant bacteria such as Rhodanobacter to become dominant groups,and the community structure tended to be stable and single.The bacterial community structure had obvious response characteristics to different cadmium pollution stresses and could be used as a sensitive index for soil quality evaluation of cadmium contaminated fields.There were a large number of Rhodanobacter,Gemmatimonadaceae-unclassified,Massilia,Candidate-Adlerbacteria-unclassified,Chitinophagaceae-unclassified,Alphaproteobacteria-unclassified,Flavobacterium and Duganella in the Cd60 group,which could be used as a reference for microbial remediation of cadmium contaminated broccoli planting fields in coastal reclamation areas.
cadmium contaminationbacterial community structurehigh throughput sequencingbroccoli
万方数据
维普
