Molecular Cloning Of Transcription Factors That Regulate The Expressions Of Hevea Brasiliensis Sucrose Transporter Gene HbSUT3and HbSUT5

Sucrose is the most important carbon and energy source for the synthesis of natural rubber in laticifer cells. So the procedure of sucrose loading into the laticifer cells determines the rubber yield. It was clear that this procedure was took in charge by HbSUT3and HbSUT5. In theory, it suggests that the key transcription factors which regulate the production of rubber tree must regulate the expressions of HbSUT3or HbSUT5. A single transcription factor frequently regulates coordinated expressions of a set of key genes for respective pathways. Cloning this kind of genes will provide more efficient candidate genes for the genetic improvement of rubber tree.In addition, HbSUT3and HbSUT5share a similar function but distinct different expression patterns in the laticifers. Revealing the molecular mechanism of the regulation of the expressions of HbSUT3and HbSUT5would be an interesting work.This study was the first time cloned transcription factors which regulate the expressions of HbSUT3and HbSUT5. It revealed the molecular regulation mechanism of the different expression patterns of HbSUT3and HbSUT5preliminarily, and laid a foundation for screening the key transcription factors which determine the rubber yield.The main results are as follows:1. The normalized full-length latex cDNA Library was constructed.2.20positive candidate genes were cloned from the cDNA library with the promoters of Hbsut3and Hbsut5as baits respectively by yeast one-hybrid system.3. Promoters of5ERF genes were cloned by adaptor-PCR.4. The expression patterns of these candidate genes were studied by real time RT-PCR technology.5. Subcellular localizations and transactivation activities of these candidate genes were analysed by the protoplast transient expression system. Despite HbDNAJ, the candidates were function as typical transcription factors.6. The expression of HbSUT3was mainly regulated by HbERF1in latex, while the expression of HbSUT5was regulated by a number of transcription factors in latex.