The Study On The Mechanism Of Mitochondrial ROS Generation Under Salt Stress In Arabidopsis

Plant growth and crop yields are greatly inhibited by salinity stress.and salt stress induces lot's of Reactive oxygen species?ROS?production,superoxide anion(O₂^.-)is the primary status in plant cells,having a unique role in plant life activities,but the O₂^.-studies have an important bottleneck of lack of accurate detection of O₂^.-method.Therefore,in the plant O₂^.-detection method of the establishment in vivo and application of the further study of the growth and development of plant response to salt stress is of great significance.Meanwhile,the cellular Ca²⁺ also participates in plants response to salt,but how does Ca²⁺ together with O₂^.-regulate plants response to salt stress is unclear.The cpYFP,specific indicator gene of O₂^.-was reconstructed in to different subcellular in Arabidopsis,the transgenic plants were analysised.NaCl treatment could induce the fluorescent intensity increase in both root tip cells and mesophyll protoplasts,indicating the generation and accumulation of O₂^.-in mitochondria.The fluorescent intensity became stronger with higher concentration of Na Cl.To further study the possible mechanism of O₂^.-generation in mitochondria induced by NaCl treatment,mesophyll cell protoplast were treated with Antimycin A,an electron transport chain?ETC?inhibitors,the fluorescence enhancement in mitochondria induced by NaCl was significantly suppressed,indicating that NaCl induced superoxide anion generation in mitochondria is closely related with ETC complex ?.MCP was also crossed with the mutants apx1 or gpx3,the fluorescent intensity in mitochondria is higher when treated with NaCl,indicating the role of both cytosolic localized apx1 and mitochondrial-localized gpx3 in ROS metabolism in mitochondria.qRT-PCR results showed that,the expression of GPX3 was lower when pretreated with Antimycin A.And application with 150 mmol/L NaCl treatment could induce rapid cellular Ca²⁺ increase in root tips by indicator YC3.6?m?,NaCl induced MCP fluorescent intensity increase was significantly inhibited by EGTA.However,when pretreated with Antimycin A,NaCl induced mitochondrial Ca²⁺ increase was not affected in root tip cells.In conclusion,Study on the mechanism of the mitochondrial O₂^.-generation under salt stress,will contribute to our understanding the mechanism of plant response to salt stimuli and provide theoretical basis for the breeding of salt-tolerant plant.