Analysis Of Potato SAUR Gene Family And Preliminary Study On The Function Of StSAUR46 Gene

Potato is one of the most widely grown food crops in the world,and the complex environmental conditions will affect the potato yield.As an early response gene in the auxin signal transduction pathway,SAUR gene plays an important role in regulating plant growth,development,responding to biotic and abiotic stresses.However,there are few reports on the study of potato SAUR gene.In this study,we identified potato SAUR gene family members and comprehensively analyzed their physicochemical properties and phylogenetic relationship.We obtained the RNA-Seq data of StSAURs genes in 12 representative tissues and in response to abiotic stress,biotic stress and hormone from the PGSC database,and further analyzed their expression patterns.Then the SAUR46 gene was cloned from the cultivar "Dongnong 303" to construct the overexpression and subcellular localization vector.Through genetic transformation of Arabidopsis,we preliminarily analyzed the phynotype of Arabidopsis,which laid the foundation for the functional study of potato SAUR gene.The main results are as follows:141 StSAURs genes were identified in the potato database.These genes are mainly distributed on the ends of chromosomes 1,4,10 and 11,their encoded amino acids with great differences in length,molecular weight,and theoretical isoelectric point.It was predicted by Plant-mPLoc software that they were mainly located in the nucleus and chloroplast,with a small amount of distribution in the cell membrane,mitochondria,and cytoplasm.The phylogenetic tree constructed by all SAUR protein sequences of potato can be clearly divided into 3 groups,a total of 6 subfamilies.According to the results of promoter prediction,StSAURs contained a large number of light-responsive elements,MYB,WRKY and HSP and other stress-related transcription factor binding sites.Colinear analysis showed that the expansion of the potato SAUR gene family was mainly derived from tandem duplication and contained95 pairs of homologous genes with Arabidopsis thaliana.It was speculated that these genes may play a conserved function in regulating plant growth and development and responding to stress.In this study,we analyzed the expression of StSAURs genes in various tissues and various stresses by mining RNA-Seq data,then divided all of StSAURs into six groups according to their hierarchical clustering methods,respectively.qRT-PCR results showed that most StSAURs genes were up-regulated in response to IAA,and some StSAURs genes were up-regulated in response to GA3,indicating that SAUR proteins may be generally involved in auxin signaling.In this study,we selected the StSAUR46 gene to construct the 35S::EGFP::StSAUR46 vector and transferred into Colombia wild-type Arabidopsis for funtional verification.The localization of StSAUR46 in the nucleus and cell membrane of tobacco cells was observed using the tobacco transient transformation method.In the preliminary analysis of the phenotype of transgenic Arabidopsis,it was found that the root length of transgenic Arabidopsis was longer than wild type under light conditions,while the hypocotyls were shorter under dark conditions than Arabidopsis thaliana.In addition,this study also found that the relative germination rate of StSAUR46 transgenic Arabidopsis under salt stress was significantly higher than that of the wild type,indicating that StSAUR46 could also improve the resistance of wild type Arabidopsis to salt stress during germination.