Cloning Of SpsLAZY1a And B Gene Promoters From Salix Psammophila And Their Expression Analysis

LAZY1 gene is involve in plant gravity response and has important regulatory effects on plant branching angle.The function and mechanism of LAZY1 gene have been studied to some extent,but there are fewer studies on the expression pattern of this gene,only in herbs.Therefore,further study on the LAZY1 promoter in woody plants is of great value for analyzing the LAZY1 expression pattern and upstream regulatory mechanism and lays research foundation for the subsequent elucidation of the LAZY1 regulatory mechanism.The coding sequences of SpsLAZY1a and Sps LAZY1b were cloned from Salix psammophila previously by our research group.Based on this research,the upstream promoter sequences of these two genes were seperated,and the cis-acting elements in them were predicted.The GUS expression vector driven by promoters of SpsLAZY1a and Sps LAZY1b were constructed.The GUS expression vectors with 4 different length promoters were constructed by deleting of the 5’end of SpsLAZY1a and transformed into84K poplar.The above obtained transgenic lines were analyzed for GUS histochemical assay and expression activity.The main results are as follows:（1）The promoters of SpsLAZY1a and Sps LAZY1b genes were obtained with lengths of 1375 bp and 1411 bp,respectively.It is predicted that these two promoters contain many identical cis-acting elements,which are mainly light-responsive elements（G-box,Box 4,GATA-motif）,methyl jasmonate-responsive elements（TGACG-motif,CGTCA-motif）,Abscisic acid responsive cis-acting element ABRE,low temperature cis-acting element LTR,ethylene responsive element ERE and gibberellin responsive element P-box.（2）The transient transformation results and GUS enzyme activity analysis of Pro _SpsLAZY1a::GUS and Pro _{Sps LAZY1b}::GUS vectors showed that promoters of SpsLAZY1a and Sps LAZY1b had promoter activities,and the GUS enzyme activity of SpsLAZY1a promoter was stronger than that of Sps LAZY1b promoter.（3）The GUS histochemical assay results of transformed 84K poplar showed that Pro _SpsLAZY1aand Pro _{Sps LAZY1b}showed blue color in terminal buds,stems,leaves and roots.Responses were mainly concentrated in the innermost cells of the cortex and phloem.（4）The results of GUS histochemical assay and enzyme activity detection of the four expression vectors deleted from the 5’end of the SpsLAZY1a promoter showed that the promoter activity gradually weakened with the deletion of the fragment length.In conclusion,the promoters of SpsLAZY1a and Sps LAZY1b genes are non-tissue-specific expression promoters,and the SpsLAZY1a and Sps LAZY1b genes are likely to have some differences in function SpsLAZY1a gene mainly exerts its function in the innermost cells of stem cortex and phloem,and is associated with plant gravity response.Deletion of fragment length in the SpsLAZY1a promoter sequence results in reduced activity.The results of this study provide an important reference for analyzing the upstream regulatory mechanism of LAZY1 gene.