Rice Rack1 Protein Regulation Mechanism Research Of Stress Lead To Oxidative Stress

The receptor of activated C kinase (RACKl) belongs to a large family of WD40repeat proteins. It played many important roles during a lot of vital physiological processes, include cellular signal transduction, protein transport, cytoskeleton polymerization/depolymerization and apoptosis.The previous study showed, RACK1was interacted with the N terminus of NADPH oxidase, RAR1, and SGT1, enhanced ROS production and regulated plant disease resistance. But it is still not clear that RACK1protein how to induced and mediated oxidative stress signaling pathways.Our study will focus on the function of OsRACK1under oxidative stress which caused by natural drought stress and Rhizoctonia solani inoculation. Transgenic rice lines of over-expressing RACK1, antisense suppressing RACK1and wild-type plants were chose as materials.The results of drought treatment showed,1、As soil moisture content declined evidently, leaf water potential and relative water content declined accordingly while the MDA level increased observably at later stage of drought stress. Compared with control, the decline of leaf water potential and relative water content of overexpressing RACK1were slower and the accumulation of MDA was repressed at later stage of drought stress. But the decline of leaf water potential and relative water content of antisense RACK1were accelerated and the accumulation of MDA was enhanced at later stage of drought stress.2、Compared with control,Overexpressing RACK1could enhanced H2O2production at normal growth, repressed O2-and H2O2accumulation at later stage of drought stress. Antisense RACK1had reverse result.3、The activities of antioxidant enzymes such as SOD、POD、CAT were increased by drought stress. Transgenic rice lines of antisense RACK1had less activities of antioxidant enlzymes than Nipponbare control, and transgenic rice lines of overexpressing RACK1had higher activities of antioxidant enlzymes than Nipponbare control.4、AsA descend evidently during drought stress. Transgenic rice lines of antisense RACK1has less AsA content than nipponbare control, transgenic rice lines of overexpressing RACK1has higher AsA content than nipponbare. GSH was first decreased and then increased. During increasing, Nipponbare control has higher GSH content than transgenic rice lines of antisense RACK1and has lower GSH content than transgenic rice lines of overexpressing RACK1. The results of rhizoctonia solani inoculation showed,1、Nipponbare control morbidity extent was lighter than transgenic rice lines of antisense RACK1and morbidity extent had no significant difference bewteen nipponbare control and transgenic rice lines of overexpressing RACK1.And rhizoctonia solani inoculation had resulted in raise of MDA content observably, Nipponbare control MDA content was lower than transgenic rice lines of antisense RACKl, MDA content had no significant difference bewteen nipponbare control and transgenic rice lines of overexpressing RACK1.2、Rhizoctonia solani inoculation had resulted in raise of O2-and H2O2contents, transgenic rice lines of antisense RACK1has higher O2-and H2O2contents than Nipponbare control after inoculated6days, transgenic rice lines of overexpressing RACK1has lower O2-and H2O2contents than Nipponbare control.3、Rhizoctonia solani inoculation had resulted in raise of antioxidant enzymes activity such as SOD、POD、CAT. Nipponbare control had higher activities of CAT and POD than transgenic rice lines of antisense RACK1, Nipponbare control had lower activities of CAT activities than transgenic rice lines of overexpressing RACK1, activities of POD had no significant difference bewteen nipponbare control and transgenic rice lines of overexpressing RACK1. And rhizoctonia solani inoculation did not effect SOD activity during anti-sense plants of RACK1, over-expressing plants of RACK1and nipponbare.4、Leaf AsA content dropped after rhizoctonia, solani inoculation, transgenic rice lines of antisense RACK1has lower AsA content than nipponbare control, transgenic rice lines of overexpressing RACK1has higher AsA content than nipponbare control.Leaf GSH content was first increased and then decreased. Nipponbare control had higher GSH content than transgenic rice lines of antisense RACK1,but GSH content had no significant difference bewteen nipponbare and over-expressing plants of RACK1.In summary, RACK1protein was able to positive regulate oxidative reaction at normal growth and positive regulate defence reaction of oxidative stress which bringed about perpetual drought stress and rhizoctonia solani inoculation.