Abstract：Phytochelatin synthase (PCS) is a protease-like enzyme that catalyzes glutathione (GSH) to form phytochelatins (PCs), and plays an important role in detoxification of heavy metals in plants. The heavy metal detoxification function of plant PCS varies according to crops varieties and doses of heavy metals. In order to study the molecular mechanism of ramie (Boehmeria nivea) PCS response to heavy metal cadmium (Cd), the p426 GDP-BnPCS1 yeast (Saccharomyces cerevisiae) expression vector was converted into wild-type and cadmium-sensitive yeast respectively, and the results showed that transgenic yeast appeared stronger cadmium tolerance under 50~100 μmol/L Cd2+ stress. In addition, BnPCS1 was overexpressed in Arabidopsis thaliana, the root length and biomass of Arabidopsis thaliana were significantly higher than those of the wild type under 100 μmol/L Cd2+ stress, and the antioxidant capacity, GSH and PCs content of Arabidopsis thaliana under cadmium stress were significantly enhanced, as well as transcription levels of AtPCS1, γ-glutamate cysteine ligase 1 (AtGCL1), glutamate synthase 1 (AtGS1), heavy metal ATPase 1 (AtHMA1) and ATP-binding cassette transporter 1 (AtATM1). The above results show that ramie BnPCS1 can actively respond to cadmium stress and enhance cadmium tolerance. The study provides a reference for ramie-tolerant molecular breeding.
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