Abiotic Stress Tolerance And Functional Mechanism Of Sep15-like Gene In Arabidopsis

Crops are faced to abiotic stress during the growth process,which often leads to an imbalance in the intracellular redox system and an increase of the endoplasmic reticulum(ER)stress,thus affecting the growth and development of the crops.Therefore,it is an important way to improve crop yield by identifying resistance-related genes and discovering their functional mechanisms and applying them to breeding.In animals,Sep 15 has been shown to be involved in the regulation of ER stress and redox homeostasis in the ER,but in plants,the role of its homologs is currently unclear.The Sep15-like cDNA and gDNA sequences of Arabidopsis thaliana,Brachypodium distachyum and Triticum aestivum were retrieved from public databases.Then,gene-specific primer pairs were designed and the full-length Sep15-like cDNA sequences were obtained.Sequence alignment analysis revealed that Sepl 5-likes across plants were highly similar and conserved in two different domains:cysteine-rich domain and thioredoxin-like folding domain.Sep15-like proteins of the three plants were all located in the ER.Transcript abundance of Sep15-like was higher in roots and leaves than in stems,and significantly up-regulated under salt and drought stresses.AtSep15-like,BdSep15-like and TaSep15-like were transferred into Arabidopsis respectively and overexpression lines were obtained.At germination stage,the germination rate of mutant was worse,and the germination rate of overexpression lines was similar to that of wild type under nonstressed conditions.However,under stressed conditions,the mutant had much lower germination percentages than the wild type,the germination rate of overexpression lines was higher than the wild type.At seedling stage,the growth of mutant was inhibited,and the growth of overexpression lines was similar to that of wild type under nonstressed conditions.However,under stressed conditions,the root length of mutant was significantly shorter,the root length of overexpression lines was longer than that of wild type,and the difference of leaves was also significant.Likewise,the overexpression lines of BdSepl5-like and TaSep15-like also showed similar phenotypes.The AtSep15-like gene could effectively relieve ER stress under stress by measuring the expression level of ER stress-related Marker gene and the content of protein carbonyls and protein thiol.The analysis of the content of ROS showed that AtSep15-like played an important role in the regulation of ROS balance.Genetic complementation experiment proved that AtSep15-like may play a role in stress tolerance by modifying AtUGGT.Our research suggested that Sep15-like could play an important role in stress tolerance by modifying UGGT and regulate ER stress and ROS homeostasis.