Arbuscular mycorrhizal fungi play a role in protecting roots of Sophora viciifolia Hance. from Pb damage associated with increased phytochelatin synthase gene expression.

Understanding the influence of arbuscular mycorrhizal (AM) fungi on the expressions of the dominant plant-related genes under heavy metal (HM) stress is important for developing strategies to reclaim polluted sites. In this study, we cloned full-length cDNAs of phytochelatin synthase gene (PCS1) and Actin of Sophora viciifolia Hance., a predominant plant in Qiandongshan lead and zinc mine, by rapid amplification of cDNA ends. Consequently, we studied the response of SvPCS1 to Funneliformis mosseae inoculation under lead stress (0, 50, and 200 µM Pb(NO3)2) at different durations (1, 3, and 7 days) using quantitative reverse-transcription polymerase chain-reaction (qRT-PCR) technique. The Pb concentrations and chlorophyll fluorescence parameters were also measured to assay Pb toxicity to Sophora viciifolia. We found that Pb concentrations in roots increased with increasing Pb application and the durations; the F v /F m , F v /F o , qP, and Y(II) decreased; NPQ rose with increasing Pb concentrations; mycorrhizal symbiosis alleviated the Pb toxicity to plants; and SvPCS1 was constitutively expressed in the roots. It was also found that F. mosseae inoculation could promote the expression of SvPCS1 with the concentration ≤ 200 µM at the exposure time shorter than 7 days.