Effect of arbuscular mycorrhizal fungus, Funneliformis fasciculatum, on detoxification of Nickel and expression of TIP genes in Lolium perenne L.

Regarding to the super-beneficial effects of arbuscular mycorrhizal fungi (AMF) on host plant in response to environmental stresses, there is a great interest for understanding the mechanisms that enable mycorrhizal plant tolerate the stress conditions. In the present study, some physiological and molecular responses induced by arbuscular mycorrhizal fungus Funneliformis fasciculatum in Ni-stressed Lolium perenne were investigated. Since heavy-metal stress is reported to alter the water relations of plant, expression of two aquaporin (AQP)-coding genes (Lptip1;1 and Lptip1;2) were studied as a molecular mechanism which may be involved in Ni-stress tolerance. The results demonstrated a pronounced positive effect of AMF on Lolium growth, water content and photosynthetic pigments content under Ni stress condition, probably through an avoidance strategy which led to the decrease in Ni accumulation in plant tissues as well as decreasing Ni translocation to the shoots. The results also indicated the mycorrhizal-induced expression of both Lptip1;1 and Lptip1;2 genes in plant roots and shoots under Ni stress. Thus, it is concluded that these two genes could be considered as stress-inducible AQP genes.