title: Microarray analysis of ripening-regulated gene expression and its modulation by 1-MCP and hexanal.
abstract: Hexanal, an inhibitor of phospholipase D, has been successfully applied for the pre- and post-harvest treatment of fruits, vegetables and flowers. Changes in gene expression induced by hexanal and the ethylene antagonist 1-MCP, were analyzed by microarray using TOM2 tomato oligo-array containing approximately 12 000 unigenes. Mature green tomato fruits were treated with 1-MCP and hexanal, RNA isolated after 10 days of storage, and labeled cDNA synthesized for microarray analysis. A large variation in gene expression profile was observed in 1-MCP-treated fruits. Genes for ethylene biosynthetic pathway enzymes such as ACC- synthase/oxidase, ethylene receptor and ethylene response factors were heavily down-regulated in 1-MCP-treated fruits. In addition, genes for key enzymes involved in cell wall degradation and carotenoid development pathways were down-regulated. Hexanal treatment significantly down-regulated ACC-synthase, and to a lesser extent, other components of ethylene signal transduction. By contrast to MCP-treated fruits, hexanal-treated fruits gradually ripened and showed higher levels of lycopene and β-carotene. GC-MS analysis of volatiles showed a higher level of major volatile components in hexanal-treated fruits. Similarities in the modulation of gene expression by hexanal and 1-MCP suggest that hexanal, in addition to being a PLD inhibitor, may also act as a weak ethylene inhibitor.
authors.affiliation: Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Krishnaraj
authors.initials: K
authors.lastname: Tiwari
authors.forename: Gopinadhan
authors.initials: G
authors.lastname: Paliyath
mesh_terms: D000447:Aldehydes / Q000494:pharmacology*; D002338:Carotenoids / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D018076:DNA, Complementary / Q000096:biosynthesis; D015536:Down-Regulation; D004798:Enzymes / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000037:antagonists & inhibitors*; D005638:Fruit / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D008190:Lyases / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010739:Phospholipase D / Q000037:antagonists & inhibitors; D012313:RNA / Q000302:isolation & purification; D015398:Signal Transduction / Q000187:drug effects; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D000447:Aldehydes; D018076:DNA, Complementary; D004798:Enzymes; D005030:Ethylenes; D055549:Volatile Organic Compounds; D002338:Carotenoids; D012313:RNA; C036216:ethylene; C010463:n-hexanal; D010739:Phospholipase D; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; D000077276:Lycopene