Cloning,Expression And Functional Analysis Of SpsTAC2 In Salix Psammophila

Salix psammophila is one of the main tree species for desert control in Northwest China.It plays an important role in maintaining the stability of sandy land ecosystem.There are various branching angles among different clones of Salix psammophila.Theresearching works on genetic mechanism of branching development have great significance foritspotential valueapplying.Therefore,this study focus on the TAC gene of IGT family related to the regulation of branching angle from Salix psammophila..In this study,the SpsTAC2 gene was cloned from Salix psammophila,then bioinformatics,tissue specific expression analysis,subcellular localization and overexpression of target genes were carried out.The results are as follows:1.The SpsTAC2 gene with 783 bp coding sequence was cloned from Salix psammophila.Online analysis showed that SpsTAC2 gene encoded 260 amino acid,which was hydrophilic proteins without transmembrane structure and signal peptide.SpsTAC2 contained typically conserved motifs of IGTfamily.The phylogenetic tree clustered SpsTAC2 with other TAC genes of polar and willow which are located on the second chromosome into the same group.The genomic gene of SpsTAC2 is 1332 bp,which contains 4 exons and 3 introns.It has similar structure to SpsTACl.2.The results of Semi-quantitativeRT-PCR and qRT-PCR indicated that SpsTAC2 gene expressed mostly in the mature leaves and phloems,the lowest in roots.3.Subcellular localization vcctovN-YFP::SpsTAC2was constructed in this study.Both of the prediction of subcellular localization and N-YFP::SpsTAC2 transient expression toonioninnerepidermalcells showed these genes located in the nucleus.4.In this study,SpsTAC2 overexpression vector was constructed and transgened to Arabidopsis thaliana,then 4 lines with SpsTAC2 overexpression were obtained.Lateral branch angles of transgenic lines were significantly broader by 8°compared with wild-type plants.Anatomical structures showed that the number of cell layers in xylem and phloem of caudex was less,the secondary growth of hypocotyl was delayed,and the xylem vessels were densercompared with wild type.5.In this study,6 lincsof SpsTAC2 overexpressing in 84K poplar were obtained.The above results indicate that the SpsTAC2iscloned whichis subordinatetoIGTgene family.SpsTAC2 gene can increased branching angle in Arabidopsis thaliana.Thisgene inhibited transverse development of phloem and xylem ofcaudex and hypocotyl,However,it can promote the development of hypocotyl vessels.This studyenriched the molecular genetic information of IGT gene family and laid a foundation for the functional study of TAC gene in Salix psammophila and provided a theoretical basis for Salix psammophila breeding.