Short inverted repeats are not inherently more stable or efficient for BSMV induced VIGS in barley roots. A HvCel1 RNA expression levels in root tissue determined by qRT-PCR (normalization to 18 S rRNA). Plants were inoculated with either BSMV-Cel1-1, BSMV-Cel1-3, BSMV-Cel1-IR, or BSMV-GFP375. Each bar represents five samples, each consisting of one plant in a pot. Error bars denote standard deviations. AU - Arbitrary units. B and C Stability of the BSMV constructs in roots of infected plants. cDNA prepared for qRT-PCR (panel A) was used for PCR with primers flanking the insert. B lanes 1-5: plants infected with BSMV-Cel1-1 (643 bp); lane 6: plasmid containing BSMV-Cel1-1 (643 bp); lane 7: plasmid containing BSMV without insert (242 bp); lanes 8-12: plants infected with BSMV-Cel1-3 (641 bp). C lanes 1-5: plants infected with BSMV-Cel1-IR (388 bp); lane 6: plasmid containing BSMV-Cel1-IR (388 bp); lane 7: plasmid containing BSMV without insert (242 bp); lane 8: plasmid containing BSMV-GFP375 (617 bp); lanes 9-12: plants infected with BSMV-GFP375 (617 bp). M5: O'Gene Ruler 50 bp DNA ladder (Fermentas). Expected lengths for the PCR products are given in brackets.