小黑杨WOX4a启动子克隆及表达活性分析OA

The stem,as one of the main storage organs of trees,plays a crucial role in wood production;enhancing its storage capacity(sink strength)is of great significance for increasing wood yield.WOX4 belongs to the WUSCHEL-related homeobox(WOX)transcription factor family and functions in maintaining vascular cambium stem cell activity and promoting cell proliferation,thereby regulating secondary growth in stems and roots.It is highly expressed during xylem development in stems and roots.In this study,RT-qPCR was used to analyze the relative expression levels of the PxWOX4a gene in different tissues.In addition,transgenic plants harboring the p PxWOX4a::GUS construct were subjected to GUS staining to further analyze the expression pattern of the PxWOX4a promoter.The results showed that WOX4a was highly expressed in the stems of Populus×xiaohei.The upstream 1 742 bp promoter region was cloned,and cis-acting element analysis revealed that it contained multiple light-responsive elements,including G-box,I-box,and Box4.A reporter vector(pBI121-p PxWOX4a::GUS)was generated and transformed into P.alba×P.glandulosa'84K'.Molecular analysis confirmed stable integration of the transgene into the genome.RT-qPCR and GUS histochemical staining demonstrated that the PxWOX4a promoter drove strong expression of the GUS gene in stems.These results indicated that the PxWOX4a promoter cloned from Populus×xiaohei exhibited stem-specific and high activity.It therefore provides a useful tool for stem-targeted genetic engineering to regulate wood formation and improve biomass yield in poplar and other forest trees.