AtOxR Interacting Protein And Study Of Its Effect On Ascorbic Acid Content

Ascorbic acid(AsA),also known as Vitamin C(VC),is present in most plant green tissues.It is an important small molecule redox agent in plants and plays an important role in response to plant growth under both abiotic and biotic stresses.The previous research of our group showed that the over-expressed AtOxR gene is related to the clearance mechanism of ROS and the change of AsA content,but the molecular mechanism of the gene responding to plant abiotic stress is not yet clear.Therefore,in-depth study of the effect of AtOxR on the level of AsA in plants at the protein level provides a scientific and theoretical basis for the study of plants' response to abiotic stress.This study explored the interaction between AtOxR and the photomorphogenic factor COP9 complex AtCSN5B subunit and its effect on AsA levels in plants.The results show that the AsA content in plants increases under light conditions and decreases under dark conditions.The AtOxR gene was strongly induced under light conditions,and suppressed under dark conditions.In contrast,the AtCSN5B gene is inhibited under light conditions and induced to express under dark conditions.The experiments of yeast two-hybrid,Bimolecule Fluorescence Complementation(BiFC)and in vitro pull-down,showed that there was an interaction between AtOxR and AtCSN5B.AtOxR gene overexpression AtOxR-OE,AtOxR mutant atoxr,AtCSN5B mutant atcsn5b and WT were further analyzed under H2O2 and NaCl stress treatment.It was found that AtOxR-OE and atcsn5b can significantly enhance the tolerance of salt stress and oxidative stress compared with WT.On the contrary,atoxr can enhance the sensitivity to salt stress and oxidative stress compared with WT.Finally,the effect of AtOxR gene on the AsA content in plants under light regulation showed that the AsA content in dark-treated AtOxR-OE was lower than that in WT,and the AsA content in light-treated AtOxR-OE was higher than that in WT.Therefore,the above research shows that the interaction between AtOxR and AtCSN5B subunit of the photomorphogenesis factor COP9 complex can affect the AsA content in plants,providing a theoretical basis for the study of plant antioxidant regulation mechanisms.