Identification Of SCAMP Family Gene In Arabidopsis And Salt Tolerance Analysis Of AtSCAMP1

Plants are affected by biotic and abiotic stresses during their growth.Saline-alkali stress is a kind of abiotic stress,which not only restricts plant growth,but also seriously affects land utilization.China is a populous country with limited land resources and food security problems.In addition,there are a large number of saline-alkali lands in China and the saline-alkali area is continuing to increase due to the coastal areas flooded with seawater affected by typhoon,thus seriously affects the land utilization rate.The main grain crops in China are all non-halophytes.Na~+/H~+antiporters play an important role in plant resistance to salt stress.Secretory carrier membrane protein(SCAMP)is a very important membrane protein in the organism.It exists in many eukaryotes and is a highly conserved protein,which is located in the endomembrane system and plasma membrane.Many studies have proved that the function of the Na~+/H~+antiporter in both mammals and plants is regulated by SCAMP.It is speculated that the SCAMP protein is related to the salt tolerance of plants,but litte has been reported.In this study,five AtSCAMP genes in Arabidopsis thaliana were isolated by PCR method,bioinformatics and subcellular localization of AtSCAMP protein were analyzed,and the role of AtSCAMP1 gene in plant salt tolerance were explored.The main results are as follows:1.Bioinformatics analysis showed that the number of amino acid residues of AtSCAMP proteins varies from 264 to 297,the molecular weight varies from 31.9 to 33.2k D,and the isoelectric point(p I)is 6.60 to 9.18.All the proteins belong to unstable hydrophobin.The AtSCAMP protein mainly contains four conformations:are?-helix(Hh),random coil(Cc),linear extension(Ee),?-sheet(Tt).AtSCAMP protein has four transmembrane domains,in which the N-terminus and C-terminus are in the cytoplasm,and there is no signal peptide.Evolutionary relationship showed that AtSCAMP1 and AtSCAMP2 proteins are relatively close;AtSCAMP3 is close to AtSCAMP4,while AtSCAMP5 has a distant relationship to other proteins.The AtSCAMP protein family is highly conserved.The length of the coding region is not much different,the similarity is as high as 72.79%,and they all have similar domains.Among them,AtSCAMP1 and AtSCAMP2 have low complexity regions,and all the proteins have composite helix regions.The AtSCAMP proteins are mainly located on the plasma membrane,followed by endoplasmic reticulum(Endoplasmic Reticulum,E.R.)and cytoplasm(Cytoplasm,Cyto).All the AtSCAMP genes contain 11 introns,indicating that their evolutionary relationship is relatively close.The cis-acting element analysis showed that the typical CAAT-box and TATA-box are common in the AtSCAMP promoters.2.Semi-quantitative PCR of AtSCAMP genes showed that AtSCAMP genes are expressed in different tissues,the expression level in roots is generally high,and the expression level in stems is generally low.The expression of AtSCAMP gene under salt stress showed a certain trend with different stress time.All the five AtSCAMP genes were up-regulated under 100 m M Na Cl treatment.3.Subcellular localization indicated that AtSCAMP1 was mainly distributed on the plasma membrane.4.Salt tolerance analysis showed that the growth of atscamp1 mutant significantly deteriorated and was weaker than that of the wild-type Arabidopsis as the salt concentration increases;The growth of AtSCAMP1 recovery lines did not differ from wild-type Arabidopsis under salt treatment.In the culture medium and soil experiment,the germination rate of the atscamp1 mutant was affected by salt treatment,and the germination rate under the same treatment was lower than that of wild-type plants;while the germination rate of the AtSCAMP1 restorer lines was not significantly different from that of wild-type Arabidopsis under salt treatment.This study found for the first time that the Arabidopsis AtSCAMP gene is sensitive to salt stress during the seed germination stage.