Characterization and comparison of the bacterial communities of rhizosphere and bulk soils from cadmium-polluted wheat fields

Li Song; Zhenzhi Pan; Yi Dai; Lin Chen; Li Zhang; Qilin Liao; Xiezhi Yu; Hongyan Guo; Guisheng Zhou

doi:10.7717/peerj.10302

Characterization and comparison of the bacterial communities of rhizosphere and bulk soils from cadmium-polluted wheat fields

PeerJ. 2020 Nov 4:8:e10302. doi: 10.7717/peerj.10302. eCollection 2020.

Authors

Li Song¹, Zhenzhi Pan¹, Yi Dai¹, Lin Chen^{1

2}, Li Zhang³, Qilin Liao⁴, Xiezhi Yu³, Hongyan Guo³, Guisheng Zhou¹

Affiliations

¹ Joint International Research Laboratory of Agriculture and Agri-Product Safety, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, Jiangsu, China.
² College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu, China.
³ State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing Univerity, Nanjing, Jiangsu, China.
⁴ Geological Survey of Jiangsu Province, Nanjing, Jiangsu, China.

Abstract

Cadmium pollution is becoming a serious problem due to its nondegradability and substantial negative influence on the normal growth of crops, thereby harming human health through the food chain. Rhizospheric bacteria play important roles in crop tolerance. However, there is little experimental evidence which demonstrates how various cadmium concentrations affect the bacterial community in wheat fields including rhizosphere microorganisms and nonrhizosphere (bulk) microorganisms. In this study, 16S rRNA amplicon sequencing technology was used to investigate bacterial communities in rhizosphere and bulk soils under different levels of pollution in terms of cadmium concentration. Both the richness and diversity of the rhizosphere microorganism community were higher under nonpolluted soil and very mild and mild cadmium-contaminated soils than compared with bulk soil, with a shift in community profile observed under severe cadmium pollution. Moreover, cadmium at various concentrations had greater influence on bacterial composition than for the nonpolluted site. In addition, redundancy analysis (RDA) and Spearman's analysis elucidated the impact of exchangeable Cd and total Cd on bacterial community abundance and composition. This study suggests that cadmium imposes a distinct effect on bacterial community, both in bulk and rhizosphere soils of wheat fields. This study increases our understanding of how bacterial communities in wheat fields shaped under different concentrations of cadmium.

Keywords: Cadmium; 16S rRNA amplicon sequencing; Microbial community; Rhizosphere; Wheat.

Grants and funding

This research was supported by the National Key Research & Development Program of China (No. 2018YFD0800201) and Graduate Practice innovation Program of Yangzhou University (No. XSJCX19_096). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.