Regulatory mechanisms of ethylene biosynthesis in response to various stimuli during maturation and ripening in fig fruit (Ficus carica L.).
In order to obtain a greater uniformity of maturation, the growth of the fig fruit (Ficus carica L.) can be stimulated by the application of either olive oil, ethrel/ethephon or auxin. The three treatments induce ethylene production in figs. In this study, we investigated the regulatory mechanisms responsible for oil, auxin and ethylene induced ethylene production in figs. The ethylene production in response to olive oil, auxin, and propylene treatments and during ripening were all induced by 1-methylcyclopropene (1-MCP) and inhibited by propylene indicating a negative feedback regulation mechanism. Three 1-aminocyclopropane-1-carboxylic acid (ACC) synthase genes (Fc-ACS1, Fc-ACS2 and Fc-ACS3) and one ACC oxidase gene (Fc-ACO1) were isolated and their expression patterns in response to either oil, propylene or auxin treatment in figs determined. The expression patterns of Fc-ACS1 and Fc-ACO1 were clearly inhibited by 1-MCP and induced by propylene in oil treated and ripe fruits indicating positive regulation by ethylene, whereas Fc-ACS2 gene expression was induced by 1-MCP and inhibited by propylene indicating negative regulation by ethylene. The Fc-ACS3 mRNA showed high level accumulation in the auxin treated fruit. The inhibition of Fc-ACS3 gene by 1-MCP in oil treated and in ripe fruits suggests that auxin and ethylene modulate the expression of this gene by multi-responsive signal transduction pathway mechanisms. We further report that the olive oil-induced ethylene in figs involves the ACC-dependent pathway and that multiple ethylene regulatory pathways are involved during maturation and ripening in figs and each specific pathway depends on the inducer/stimulus.
Owino
W O
WO
Department of Food Science and Technology, Faculty of Agriculture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, Kenya. willis@gene.tsukuba.ac.jp
Manabe
Y
Y
Mathooko
F M
FM
Kubo
Y
Y
Inaba
A
A
D000475:Alkenes / Q000494:pharmacology; D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D001483:Base Sequence; D003521:Cyclopropanes / Q000494:pharmacology; D005030:Ethylenes / Q000096:biosynthesis*; D030681:Ficus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D005638:Fruit / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000494:pharmacology; D008190:Lyases / Q000378:metabolism; D008969:Molecular Sequence Data; D000069463:Olive Oil; D010937:Plant Growth Regulators / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D000475:Alkenes; D003521:Cyclopropanes; D005030:Ethylenes; D007210:Indoleacetic Acids; D000069463:Olive Oil; D010937:Plant Growth Regulators; D010938:Plant Oils; D010940:Plant Proteins; D012333:RNA, Messenger; C036216:ethylene; C013658:propylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; C412563:1-methylcyclopropene