Some physiological and molecular changes induced by TiO2 nanoparticles in chickpea plants during cold stress

In this experiment, effects of TiO2 nanoparticles (NPs) on some physiologo-molecular responses were studied in two chickpea (Cicer arietimun L.) genotypes differing in cold sensitivity (tolerant, Sel96Th11439 and susceptible, ILC533) during cold stress (4°C). The data analysis showed that hydrogen peroxide (H2O2) content increased significantly under cold stress in susceptible plants than in tolerant ones. TiO2 NPs caused a significant decrease in H2O2 content, so that tolerant plants had lower H2O2 content than susceptible ones. This decrease often was accompanied with higher ascorbate peroxidase activity to cell protection against cold stress in tolerant plants compared to susceptible plants, as well as in plants treated with TiO2 NPs compared to control plants. That indicated increased tolerance degree to cold as the result of protection of cells against reactive oxygen species (ROS). Also, in plants treated with TiO2 NPs Ascorbate peroxidase, Chromatin remodeling complex, Chapronin-60 protein relative genes expression increased than control plant and this increase were more obvious in tolerant genotype compared to susceptible ones. Therefore, chickpea tolerance responses to cold stress occur after TiO2 NPs application on plants accompanied with upregulation of transcription level regulator and protective genes and genes involved in ROS scavenging. This improves the ability of survival or recovery of cell damage during cold stress in chickpea plants and probably leads to stable yield in field environments.