Effect of TiO2 nanoparticles on relative expression of some genes involved in response to cold stress in chickpea

In this experiment, some physiological responses such as electrolyte leakage index (ELI) and relative expression of receptor-like kinase (RLK), ethylene response transcription factor (ERF) and vacuolar sorting receptor 6 (VSR-6) by real time PCR were studied in two genotypes of chickpea (Cicer arietimun L.) which are different in cold sensitivity (tolerant, Sel96Th11439 and susceptible, ILC533) during cold stress (4°C) and TiO2 nanoparticles (NPs) (5 ppm). Under cold stress, TiO2 NPs caused a significant decrease in ELI, so that tolerant plants had lower ELI than susceptible ones. Therefore, the applied nanoparticles not only did not disturb the cell membrane but also are caused to decline of damages during cold stress. During cold stress, tolerant plants compared to susceptible ones, as well as in plants treated with TiO2 NPs compared to control plants showed significant increase in transcription levels of RLK, ERF and VSR-6 genes. An increase in expression of these genes is probably effective in the survival or recovery of plant because along with their increase, cell damages (ELI) resulted from reactive oxygen species (ROS) are decreased. Therefore, rapid and transient up-regulation of these genes particularly may be considered as functional markers in acclimation process in chickpea against cold stress. This finding that chickpea plants treated with TiO2 show more tolerance against cold stress has created new application for nanoparticles and may be led to the stable yield under stress in these plants.