Potential of Wheat dwarf virus (Geminiviridae: Mastrevirus) Truncated Promoter for Improvement of Transgene Expression in Rice

Wheat dwarf virus (WDV) is a monocotyledonous plant-infecting virus that causes economical loss to cereal cultivations annually. The objective of this study was to use Cauliflower mosaic virus 35S promoter in combination with WDV large intergenic region (LIR) in rice (Oryza sativa L.) plant. Herein, a partial sequence from the genome of an Iranian isolate of WDV was used to synthesize a promoter for improvement of transgene expression in rice cultivars including Champa, Hashemi and Najafi. The promoter was cloned into pCAMBIA1304 and transferred into rice cells using in planta method. PCR, hygromycin resistance and in vivo expression of green fluorescent protein (mGFP5) were used for evaluating the efficiency of the synthesized promoter. The results showed that the WDV LIR can act as an efficient promoter for transgene expression in rice plant. Moreover, a significant difference was found between transformation rates in different rice cultivars; thus, Champa and Najafi cultivars showed the highest and lowest rate of transformation, respectively. WDV LIR was used to design a novel promoter for gene expression in rice cells. PCR assay, phenotypic experiment (antibiotic selection and GFP expression) and nucleotide sequencing showed that LIR is a promising source for the improvement of transgene expression within cells of monocotyledonous plants.