Abstract
Barley stripe mosaic virus (BSMV) works as a vector in the monocot plants, to deliver a small segment of gene for post�transcriptional modification through the Virus-induced gene silencing (VIGS) mechanism. VIGS is derived from the plant defense mechanism as a tool to understand the gene function and the expected phenotype in a short time. Moreover, VIGS mechanism provides a large-scale analysis of screening phenotype with a low cost relatively compared to the stable transformation in the monocot plants. This study aimed to examine the microprojectile bombardment by biolistic particle bombardment device (gene gun) compared to the agro-Infiltration method with Agrobacterium tumefaciens to deliver the BSMV with genes to Brachypodium distachyon. The green fluorescent protein (GFP) and Phytoene desaturase gene (BdPDS) worked as a visual marker to confirm the conversion of pCass4-RZ-ND18 plasmid to the intact BSMV. The findings showed that the GFP signals appeared during the agro-Infiltration approach while the BSMV during the microprojectile bombardment approach failed to express the foreign GFP gene. Furthermore, the knockdown of BdPDS gene phenotype appears as a photo-belched strips on the B. distachyon leaves after inoculation of the BSMV with agro-Infiltration pathway. Conversely, B. distachyon leaves which injected through the microprojectile bombardment approach has no significant changes in the phenotype compared to the WT. This phenotype was confirmed by the qRT-PCR results which showed a highly significant decrease in the PDS expression level during the agro-Infiltration approach only. Eventually, the agro-Infiltration approach is much effective than the microprojectile bombardment approach although the former approach needs much time and many confirmation steps.

Key words: Barley stripe mosaic virus, virus-induced gene silencing, Phytoene desaturase, green fluorescent protein, agro-infiltration, microprojectile bombardment.