Physiological and transcriptomic characterization of cadmium toxicity in Moso bamboo (Phyllostachys edulis), a non-timber forest species.

Cadmium pollution in Moso bamboo forests poses a potential threat to the sustainable development of the bamboo industry. However, the effects of cadmium toxicity on Moso growth and its mechanisms of adaptation to cadmium stress are poorly understood. In this study, the physiological and transcriptional response of Moso to cadmium stress was investigated in detail using Moso seedlings in a hydroponic system. Cadmium toxicity severely inhibited the growth of roots but had little effect on biomass accumulation in the aerial parts. Cadmium accumulation in roots and aerial parts increased as external cadmium increased, with cadmium mainly localized in the epidermis and pericycle cells in the roots. The uptake and root-to-shoot translocation of cadmium was stimulated, but the photosynthetic process was suppressed under cadmium stress. A total of 3469 differentially expressed genes were identified from the transcriptome profile and those involved in cadmium uptake, transportation and detoxification were analyzed as candidates for having roles in adaptation to cadmium stress. The results suggested that Moso is highly efficient in cadmium uptake, xylem loading and translocation, as well as having a high capacity for cadmium accumulation. This work also provided basic information on physiological and transcriptional responses of Moso to cadmium toxicity.