Microbial communities from the rhizosphere of the arsenichyperaccumulating plant Pteris vittata and non-rhizosphere samples were examined using GeoChip 3.0 (Xiong et al., 2010) . The functional gene diversity was significantly correlated with As concentration. Interestingly, As contaminated rhizosphere samples had higher functional gene diversity than non-rhizosphere samples even though the non-rhizosphere samples had a lower level of As. In addition, greater numbers of As resistance genes, with higher signal intensities, were detected in rhizosphere samples compared to non-rhizosphere samples and very few genes were detected in both environments, suggesting that the rhizosphere and non-rhizosphere microbial communities were distinct. Results suggested that the P. vittata rhizosphere may protect the microbial communities from As contamination.