Chalcone synthase as a reporter in virus-induced gene silencing studies of flower senescence

• Published in: Plant molecular biology 2004-07, Vol.55 (4), p.521-530
• Main Authors: Chen, J.C, Jiang, C.Z, Gookin, T, Hunter, D, Clarke, D.G, Reid, M.S
• Format: Article
• Language: English
• Subjects: Acyltransferases - genetics; Acyltransferases - metabolism; Agrobacterium tumefaciens; agroinfection; Amino Acid Oxidoreductases - genetics; Amino Acid Oxidoreductases - metabolism; aminocyclopropanecarboxylate oxidase; Anthocyanins - biosynthesis; CHS gene; Cultivars; Ethylenes - biosynthesis; Flowers; Flowers & plants; Flowers - genetics; Flowers - physiology; gene expression; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Gene Silencing; Genetic Markers - genetics; infection; Leaves; messenger RNA; naringenin-chalcone synthase; Nicotiana - virology; oxygenases; PDS gene; Petunia; Petunia - genetics; Petunia - metabolism; Petunia hybrida; Phenotype; Photobleaching; phytoene desaturase; Plant Viruses - genetics; Plants, Genetically Modified; Plasmids - genetics; Pollen - physiology; reporter genes; Reverse Transcriptase Polymerase Chain Reaction; RNA, Plant - genetics; RNA, Plant - metabolism; senescence; Time Factors; Tobacco rattle virus; Transformation, Genetic; virus-induced gene silencing; White people
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-004-0590-7

Agrobacterium-mediated infection of petunia (Petunia hybrida) plants with tobacco rattle virus (TRV) bearing fragments of Petunia genes resulted in systemic infection and virus-induced gene silencing (VIGS) of the homologous host genes. Infection with TRV containing a phytoene desaturase (PDS) fragment resulted in reduced abundance of PDS transcripts and typical photobleaching of photosynthetic tissues. Infection with TRV containing a chalcone synthase (CHS) fragment resulted in silencing of anthocyanin production in infected flowers. The silencing phenotype ranged from scattered white spots on the normal purple background to entirely white flowers. Symptoms in the V26 cultivar were a diffuse mosaic, but infection of some purple-flowered commercial cultivars resulted in large white sectors and even entirely white flowers. Abundance of CHS transcripts in the white flowers was less than 4% of that in purple flowers on the same plant. Infection with TRV containing a tandem construct of PDS and CHS resulted in leaf photobleaching and white patterns on the flowers. Transcripts of CHS and PDS were reduced both in leaves and in flowers confirming simultaneous silencing of both genes by the tandem construct. We tested the effects of infection with TRV containing CHS and a fragment of a petunia gene encoding for 1-aminocyclopropane-1-carboxylate oxidase (ACO4) Abundance of transcripts encoding ACO4 and ACO1 were reduced (by 5% and 20%, respectively) in infected flowers. Whether the flowers were treated with ACC or pollinated, the white (silenced) flowers or flower sectors produced less ethylene and senesced later than purple (non-silenced) tissues. These results indicate the value of VIGS with tandem constructs containing CHS as reporter and a target gene as a tool for examining the function of floral-associated genes.