ABSTRACT
Virus-induced gene silencing (VIGS) is a powerful gene-silencing tool that has been intensively applied in plants. To data, the application of VIGS in rubber tree has not yet been reported. In this study, we described the efficient gene silencing in rubber tree by VIGS. The gene encoding Hevea brasiliensis phytoene desaturase (HbPDS) was identified in rubber tree genome. Small interfering RNAs from HbPDS and the silencing gene fragment were predicted and a length of 399 bp was selected to be tested. We showed that the tobacco rattle virus (TRV)-VIGS could induce effective HbPDS silencing in rubber tree. This study was the first to report VIGS in rubber tree. The present TRV-VIGS method could be used to perform reverse genetic approaches to identify unknown gene functions and might be further applied to produce gene silenced rubber tree plants, to advance functional gene of rubber tree.
Subject(s)
Gene Silencing/physiology , Genes, Plant , Hevea/genetics , Plant Viruses/physiology , RNA, Small Interfering/geneticsABSTRACT
Farnesyl pyrophosphate synthase (FPS) is a key enzyme that catalyzes the formation of farnesyl pyrophosphate, the main initiator for rubber chain initiation in Hevea brasiliensis Muell. Arg. The transcriptional regulatory mechanisms of the FPS gene still not well understood. Here, a WRKY transcription factor designated HbWRKY27 was obtained by screening the latex cDNA library applied the HbFPS1 promoter as bait. HbWRKY27 interacted with the HbFPS1 promoter was further identified by individual Y1H and EMSA assays. HbWRKY27 belongs to group IIe WRKY subfamily which contains a typical WRKY domain and C-X5-CX23-HXH motif. HbWRKY27 was localized to the nucleus. HbWRKY27 predominantly accumulated in latex. HbWRKY27 was up-regulated in latex by ethrel, salicylic acid, abscisic acid, and methyl jasmonate treatment. Transient expression of HbWRKY27 led to increasing the activity of the HbFPS1 promoter in tobacco plant, suggesting that HbWRKY27 positively regulates the HbFPS1 expression. Taken together, an upstream transcription factor of the key natural rubber biosynthesis gene HbFPS1 was identified and this study will provide novel transcriptional regulatory mechanisms of the FPS gene in Hevea brasiliensis.