The soil microbial communities play an important role in plant health, however, the relationship between the below-ground microbiome and above-ground plant health remains unclear. To reveal such a relationship, we analyzed soil microbial communities through sequencing of 16S rRNA gene amplicons from 15 different tobacco fields with different levels of wilt disease in the central south part of China. We found that plant health was related to the soil microbial diversity as plants may benefit from the diverse microbial communities. Also, those 15 fields were grouped into ‘healthy’ and ‘infected’ samples based upon soil microbial community composition analyses such as unweighted paired-group method with arithmetic means (UPGMA) and principle component analysis (PCA), and furthermore, molecular ecological network analysis indicated that some potential plant-beneficial microbial groups, e.g. Bacillus and Actinobacteria could act as network key taxa, thus reducing the chance of plant soil-borne pathogen invasion. In addition, we propose that a more complex soil ecology network may help suppress tobacco wilt, which was also consistent with highly diversity and composition with plant-beneficial microbial groups. This study provides new insights into our understanding the relationship between the soil microbiome and plant health.

In this study, the production and compositional analysis of exopolysaccharides produced by Bacillus cereus KMS3-1 grown in metal amended conditions were investigated. In addition, the metal adsorption efficacy of exopolysaccharides (EPS) produced by KMS3-1 strain was evaluated in a batch mode. Increased production of exopolysaccharides by KMS3-1 strain was observed while growing under metal amended conditions (100 mg/L) and also, the yield was in the order of Pb(II)>Cu(II)>Cd(II)>Control. Characterization of EPS using FT-IR, XRD, and SEM analysis revealed that the EPS can interact with metal ions through their functional groups (O‒H, CH, C˭O, C‒O, and C‒C˭O) and assist the detoxification process. Further, equilibrium results were fitted with the Langmuir model and notably, the maximum adsorption capacity (Q_max) of EPS for Cd(II), Cu(II), and Pb(II) found to be 54.05, 71.42, and 78.74 mg/g, respectively. To the best of our knowledge, EPS demonstrating proficient metal adsorption was substantiated by XRD analysis in this study. Owing to good adsorbing nature, the exopolysaccharides could be used as chelating substances for wastewater treatment.