Physiological and Transcriptome Analysis of Response of Soybean (Glycine Max) To Cd Stress Under Elevated Co2 Concentration

Elevated atmospheric CO2 concentration (eCO2 ) may mitigate the adverse impacts of heavy metals. Cd stress significantly decreased the weight of leaves and roots by 42.3% and 45.5%, while eCO2 significantly increased them under Cd stress. A significant increase in the content of malondialdehyde (MDA) and H2O2 was observed under Cd stress, along with a significant increase in the content of proline and soluble sugars and the activity of peroxidase, superoxide dismutase, catalase and reactive oxygen species. eCO2 significantly decreased the content of MDA and H2O2. The content of proline and soluble sugars were greater under the combination of eCO2 and Cd stress than that of under Cd alone due to the inhibited proline dehydrogenase activity and enhanced endogenous proline accumulation, thus alleviating Cd stress in soybean. The genes encoding glutathione synthetase and phytochelatin synthase subjected to Cd stress under eCO2 were upregulated. The MAPK and some transcription factors such as bHLH, AP2/ERF and WRKY may alter their expressions involved in eCO2 alleviating the effects of Cd stress. These findings provided a basis for improving the ability of plants to respond to Cd stress under climate change scenario.