Study Of Protein Disulfide Isomerase Gene Family Of Salt Tolerance Function In Zoysiagrass(Zoysia Matrella)

Specifically,about 80%of saline alkaliwastelands require to be improved and utilized in China.Turfgrasses are important components of ecological systems,usually as an important pioneer plant in saline alkali soil improvement as pioneer plants.For this reason,breeding of salt-tolerant turf grasses is the basic measure to improve the greening and construction of saline soil,and it is also an important direction object for breeders in recent years.Zoysia matrella is a perennial warm season turfgrass belonging to Gramineae,Chloridoideae,is a salt-tolerant perennial warm season turfgrass species.The mechanisms of salt-tolerance in halophytes including Zoysia matrella are currently unclear,especially at the molecular level.Protein disulfide isomerase(PDI)and PDI-like proteins(PDILs),belonging to thioredoxin(Trx)superfamily,is an important folding catalyst in the endoplasmic reticulum,which can promote the correct folding of the protein by catalyzing the formation of disulfide bonds(oxidative activity)of the protein and catalyzing the misalignment of the disulfide bond rearrangement(isomerase activity).In this study,we firstly analyzed the function of protein disulfide isomerase(ZmPDIs)in salt-tolerance regulation in Zoysia matrella.A series of studies,including comparative analyses of phylogenetic relationship and gene structure of the cloned ZmPDIs with known PDI genes,RT-qPCR analyses of ZmPDI genes in different tissues with and without salt stress treatment,and yeast phenotypic complement analyses.Results of these studies not only expand our understanding of salt tolerance mechanisms in Zoysia grasses and other turfgrass species,but also provide important theoretical basis for breeding of salt-tolerant turfgrass cultivars.The main conclusions of this paper include:-1.Five ZmPDI genes were successfully cloned from Zoysia matrella.Systems evolutionary and gene structure analyses collectively indicated that the five ZmPDI genes belong to the PDI gene family,and have high sequence homology with known PDIs of Arabidopsis,maize and rice.Notably,the sequence of ZmPDI1,ZmPDI2 and ZmPDIS are highly similar,implying that they were possibly formed through gene duplication events.2.Real-time PCR analyses indicated that all the 5 ZmPDI genes were preferentially expressed in the stems.Under salt treatments,the expression of 5 ZMPDI genes were all significantly increased,suggesting their expression is salt-induced.3.pYES2 vectors containing different ZmPDI genes were transformed into yeast deletion mutant EUG1.Yeast growth comparasion indicated that four genes,ZMPDI1,ZMPDI 2,ZmPDI 3 and ZmPDI 4 could prmote the growth of mutant yeast cells in SD/-His/-Ura mediums containing 500mM NaCl.These observations suggested that these 4 ZmPDI proteins have the biological function to improve the salt-tolerance of cells.