Comparative transcriptome combined with physiological analyses revealed key factors for differential cadmium tolerance in two contrasting hemp (Cannabis sativa L.) cultivars

摘要

Cadmium(Cd) is a widespread and one of the most toxic heavy metals, threatening human health. As a pioneer fiber crop, hemp (Cannabis sativa L.) has a great potential in Cd-polluted soil repair, but molecular mechanisams of hemp supporting the process of soil decontamination are still unknown. In this study, the key factors for differential Cd tolerance in two contrasting hemp cultivars (Cd-tolerant: Ym, Cd-sensitive: Nx) were investigated. Ym has a stronger transport and accumulation capacity than Nx. Furthermore, Cd detoxification in Ym is stronger than in Nx. Phenotype and 3,3'-diaminobenzidine(DAB) staining observation indicated that Ym was more tolerant to cadmium stress than Nx, as well as malondialdehyde(MDA) contents, superoxide dismutase (SOD) and peroxidase(POD) activities showed Ym has a stronger detoxification ability than Nx. Compared the transcriptome analysis between Ym and Nx, many genes involved in heavy metal transport and oxidation-reduction progress were identified between the two varieties. A schematic representation of main processes about differential Cd transport and detoxification was described, based on these results, which suggested that the higher Cd tolerance in Ym due to the key genes encoding some specific Cd transporter, defense system, special proteins that have a high expression in Ym.