Ethylene insensitive mutation alleviates cadmium-induced photosynthesis impairment in Arabidopsis plants

Ethylene insensitive (ein) mutation in Arabidopsis has been demonstrated to improve cadmium (Cd) tolerance, but the involved mechanisms still need to be clarified. In this study, the photosynthesis-related processes were addressed by comparatively analyzing the performance between Arabidopsis wild type (WT) plants and ethylene insensitive mutant ein2-1 under Cd stress. Exposure to 50 mu M CdCl2 for 48 h decreased chlorophyll contents, Rubisco activity, and net photosynthetic rate, respectively, by 23, 24, and 28% in WT plants, while 13, 11, and 15% in the mutant, when compared with their control levels (without Cd). The expressions of photosynthesis-related genes presented a global down-regulation in WT plants, while they exhibited a mixed pattern in ein2-1 under Cd stress. The genes involved in carbon metabolisms generally expressed at a higher level in the mutant under Cd stress. Collectively, these data suggested that the role of ethylene in Arabidopsis plant response to Cd was correlated with the transcriptional regulation of genes related to photosynthesis and carbon metabolisms.