| RUB（Rubredoxins）is a class of proteins located on the thylakoid membrane of chloroplasts.In plants,RUB participates in ion balance homeostasis,osmotic balance,and ROS clearance,and plays an important role in the process of saline-alkali response,but the molecular mechanism involved in regulation is still unclear.In this study,the halo-wood plant Salix linearistipularis was used as the material,and the SaRUB gene was cloned from Salix linearistipularis using molecular genetics.Bioinformatics analysis showed that the open reading frame of SaRUB is 819 bp long,encoding 272 amino acids,the protein molecular weight is about 28.73 kDa,the isoelectric point is 9.62,and the negative value of GRAVY is a hydrophilic protein.SaRUB is composed of 1 PDZ domain and 1 Rubredoxin domain,with an N-terminal signal peptide（sp）and a transmembrane domain.Phylogenetic tree analysis shows that SaRUB has the closest phylogenetic relationship with Arabidopsis NP568342.RT-qPCR analysis showed that SaRUB had the highest expression in leaves and the lowest expression in seeds.After saline（200 mmol/LNaCl,75 mmol/LNa2CO3,1 00 mmol/LNaHCO3）and oxidation（8 mmol/L H2O2）stress,SaRUB gene expression in the roots and leaves of Salix linearistipularis was induced,suggesting that SaRUB may be involved various stress response processes.Subcellular localization analysis showed that SaRUB was localized in the chloroplast.Under salt stress（1.3 mol/L NaCl）,alkali stress（15 mmol/L Na2CO3,26 mmol/L NaHCO3）,osmotic stress（1.8 mol/L Sorbitol）and oxidative stress（2.8 mmol/L H2O2）,the transgenic SaRUB yeast grows better than the control yeast strain.Therefore,SaRUB gene may increase the resistance of yeast strains to stress.The phenotype analysis of transgenic Arabidopsis and mutants showed that after stress treatment（100 mmol/L NaCl,3 mmol/L NaHCO3,and 2 mmol/L Na2CO3）,the root length and fresh weight of the SaRUB Arabidopsis strains overexpression were obvious better than wild-type Arabidopsis and mutant plants,and the growth of atrub（SALK018190）mutant is severely inhibited.DAB and NBT staining and H2O2 content analysis showed that the content of ROS and H2O2 in Arabidopsis overexpressing the SaRUB gene was significantly lower than that of wild-type plants and mutant plants.It is speculated that SaRUB can improve the resistance of plants to various stresses by eliminating ROS.In summary,SaRUB participates in the elimination of ROS in plants and plays an important role in response to stresses such as salinity.These results provide evidence for in-depth understanding of the molecular regulation mechanism of the salinity response of Salix linearistipularis RUB. |
