Microbial Diversity Analysis in Cadmium-Polluted Soils

The Shannon index, ACE and Chao 1 data and fungal taxa abundance were analysed using GraphPad Prism 5.0 (GraphPad Software Inc., San Diego, CA, USA), and the significant differences in the microbial alpha diversity between different cadmium treatments were calculated using Duncan's multiple test at p<0.05, p<0.01 or p<0.001, respectively. Total and available cadmium were calculated using SAS version 9.1(SAS Institute Inc., Cary, NC, USA). One-way-analysis of variance (ANOVA) and Spearman's correlations were also calculated using SAS version 9.1(SAS Institute Inc., USA). To determine the potential differences in the bacterial and fungal communities across compartments and chromium-added treatments, a heatmap of Spearman's rank correlation was generated using the package “gpplot” (Oksanen et al., 2012) in R (v3.6.2) based on Bray-Curtis dissimilarity. Canonical discriminant analysis (CDA) was performed to calculate the environmental factors that have the most remarkable influence on the microbial and fungal communities by CANOCO 5.0 (Biometrics Wageningen, Netherlands) [72 , 73 ]. LEfSe analysis was applied using the version at https://huttenhower.sph.harvard.edu/galaxy/ [74 (link)].