Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress.
We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription.
Mathooko
F M
FM
Laboratory of Postharvest Agriculture, Faculty of Agriculture, Okayama University, Japan. mathooko@cc.okayama-u.ac.jp
Mwaniki
M W
MW
Nakatsuka
A
A
Shiomi
S
S
Kubo
Y
Y
Inaba
A
A
Nakamura
R
R
D001483:Base Sequence; D002245:Carbon Dioxide; D018553:Cucumis sativus / Q000201:enzymology* / Q000235:genetics*; D003513:Cycloheximide / Q000494:pharmacology; D018744:DNA, Plant; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D007700:Kinetics; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D047428:Protein Kinase Inhibitors
D018744:DNA, Plant; D004791:Enzyme Inhibitors; D047428:Protein Kinase Inhibitors; D002245:Carbon Dioxide; D003513:Cycloheximide; D010749:Phosphoprotein Phosphatases; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase