Expression Analysis Of Storage Protein Avenin-like B Gene Promoter From Wheat (Triticum Aestivum)

Wheat is one of the world's most important food crops, and its production is about 6 million tons every year worldwide,and provides daily requirements of protein and calories for more than 35% of the global population. Wheat processing quality is closely related to the composition of storage protein.Therefore,in order to improve its quanlity, transforming high-quality storage protein genes into wheat by genetic engineering methods is currently the main topic of wheat genetics and breeding. Isolation and characterization of endosperm-specific promoter which can drive high-quality wheat storage protein genes with high level of expression, will guarantee the realization of this goal. In the present research,by using the previously constructed five avenin-like b gene promoters to drive gus gene expression vectors with different deletions,the expression analysis of gus gene driven by these promoters was performed in transgenic tobacco.The main results are as follows:(1)Expression vectors of pALP-3, pALP-6, pALP-8, pALP-10, pALP-17 constructed by deletions with different lengths were transformed into tobacco by Agrobacterium- mediated transformation technology.And the positive transgenic plants were selected using PCR screening.(2)The results of GUS histochemical staining of positive transgenic plants confirmed that the avenin-like b promoter is endosperm-specific,and that the GCN4 and the Skn-Ⅰmotif are essectial for endosperm-specific expression.(3)Fluorescence quantitative analysis of transgenic positive plants showed that relative expression activities were 273.06 nmol/mg protein/hr, 314.50 nmol/mg protein/hr, 447.86 nmol/mg protein/hr, 233.74 nmol/mg protein/hr and 173.68 nmol/mg protein/hr, respectively for vectors pALP-3, pALP-6, pALP-8, pALP-10 and pALP-17. The transgenic tobacco plants which harbored 800 bp sequence of the promoter had the highest GUS activity.Isolation and functional analysis of wheat endosperm-specific promoters can contribute to study the mechanism of seed development and the regulation mechanism of endosperm-specific genes.The endosperm-specific promoters can be used to gene modification in plant genetic engineering.Thus, it not only has potential applications in theorey but also in practial applications.