Functional Characterization of a Bidirectional Promoter from Wheat Dwarf India Virus (WDIV) using an Agrobacterium-mediated Transformation in Wheat and Arabidopsis

摘要

Wheat dwarf India virus is a single stranded (ss) circular leafhopper transmitted mastrevirus (family; Geminiviridae)that infects wheat in India. Transcription of WDIV genes is controlled by the cis-regulatory element known as large intergenicregion (LIR). LIR acts as a promoter that regulates the replication of viral genome as well as transcription of WDIV genes inboth virion-sense (V) and complementary-sense (C). The complementary-sense and virion-sense transcriptional regulatorycomponents are located in the opposite orientations of the large intergenic region, therefore considered as bidirectionalpromoter. We studied regulation of putative WDIV promoter by cloning β-glucuronidase (GUS) reporter gene in bothorientations, up- and downstream of LIR, in a plant transformation vector. Agrobacterium mediated transient and stabletransformation in Triticum aestivum calli and Arabidopsis thaliana, respectively, revealed the functional activity of C and Vsense promoter through histochemical staining in GUS transformed tissues. Further, real-time PCR and fluorometric assay ofGUS were used to measure the activity of WDIV C-sense and V-sense promoter. Presence of cis-regulatory elements (CREs) andbasic conserved elements were also found within the bidirectional promoters of WDIV. The present study will be helpful inunderstanding the transcriptional regulation of WDIV gene products in monocot and dicot plants.