Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 2003
Publication Date: January 20, 2004
Citation: WEILAND, J.J., EDWARDS, M.C. APPROACHES FOR GENE SILENCING IN SUGARBEET. PLANT AND ANIMAL GENOME XII ABSTRACTS. 2004. Abstr. No. P880. p. 291. Technical Abstract: Gene silencing has emerged as a powerful tool for the generation of expression knock-outs of cloned genes in plants. The RNA virus barley stripe mosaic virus (BSMV) is being investigated as a tool for silencing genes in Chenopodium spp and sugarbeet (Beta vulgaris L.), hosts which support local infection by this virus. Using infectious cDNA clones of BSMV strain ND18, portions of the cDNA sequences encoding barley phytoene desaturase (HvPDS), sugarbeet magnesium chelatase (BvMgCh), and the sugarbeet small subunit of ribulose bisphosphate carboxylase (Rubisco; BvssuRbc) were in inserted into RNA gamma genomic clone. Inoculation of barley (cv 'Black Hulless') with these constructs lead to the development of infection symptoms that differed between the isolates as compared to infection with wild-type ND18 virus. Intense white bleaching of barley tissue infected with the isolate harboring the HvPDS sequence was consistent with the silencing of the endogenous mRNA for this gene. The inoculation of Chenopodium amaranticolor and C. quinoa with isolates harboring the BvssuRbc sequence resulted in the rapid (5 d.p.i) development of chlorosis on the inoculated leaf. The accumulation of proteins of sizes similar to both the small and large subunits of Rubisco were significantly reduced in extracts from these leaves as compared to leaves inoculated with BSMV strain ND18. Sugarbeet inoculated with these silencing constructs exhibited no phenotypic difference compared to inoculation with strain ND18. A comparison of mRNA levels targeted by these constructs, and the proteins they encode, in extracts prepared from inoculated sugarbeet plants currently is being made.