Effect of arbuscular mycorrhizal fungi inoculation on cold stress-induced oxidative damage in leaves of Elymus nutans Griseb

Abstract

To investigate the effect of arbuscular mycorrhizal fungi (AMF) inoculation and short-term cold exposer on Elymus nutans Griseb, 45day old seedlings of two cultivars, Zhengdao (ZD) and Kangma (KM), were subjected to a 5day cold treatment after inoculated with Glomus mosseae. The effects of AMF on the physiology of the two cultivars were determined, and we were especially interested in oxidative indexes under cold stress. Accumulation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide, was very high in cold-stressed plants and caused lipid peroxidation in membranes, which measured as relative electrolyte leakage (REL), malondialdehyde (MDA) content. Less oxidative damage was detected in AMF colonized plants, which was associated with higher activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). Mycorrhizal inoculum application promoted plant growth and enhanced the level of chlorophyll and antioxidant compounds such as glutathione and soluble sugars. We also measured the extent of mycorrhizal colonization. These protective mechanisms were found to be more efficient in temperature-tolerant KM than temperature-sensitive ZD. Overall, we suggest that AMF inoculation can improve plant resistance to cold stress in E. nuatans seedlings by directly scavenging ROS and by modulating redox balance and other defense mechanisms.