TY - JOUR
T1 - Differential regulation of genes encoding ethylene biosynthesis enzymes and ethylene response sensor ortholog during ripening and in response to wounding in avocados
AU - Owino, Willis Omondi
AU - Nakano, Ryohei
AU - Kubo, Yasutaka
AU - Inaba, Akitsugu
PY - 2002
Y1 - 2002
N2 - We investigated the differential regulation of two 1-aminocyclopropane-1-carboxylate synthase (ACS) genes, one 1-aminocyclopropane-1-carboxylate oxidase (ACO) gene and one ethylene response sensor (ERS1) ortholog during ripening and in response to wounding in avocados (Persea americana Mill. 'Bacon'). The 1-aminocyclopropane-1-carboxylate (ACC) content, ACS activity and detectable expression of PA-ACS1 mRNA increased and reached a maximum prior to the climacteric peak, whereas Ace activity and the PA-ACO mRNA levels increased markedly only at the upsurge of ripening ethylene. A basal level of PA-ERS1 transcript was detected as from harvest, however, PA-ERS1 transcript was hyper-induced at the climacteric peak of ethylene production. 1-Methylcyclopropene (1-MCP) application at thepreclimacteric and the onset of climacteric stages inhibited the ACS and ACO activities, the transcription of PA-ACS1 and suppressed PA-ACO and PA-ERS1 mRNAs to trace levels. Discontinuation of 1-MCP treatment led to super-induction of PA-ACS1, PA-ACO, and PA-ERS1 transcripts. Wound induced ethylene biosynthesis and woundinduced-induced PA-ACS2 mRNA accumulation were enhanced by 1-MCP, whereas wound-induced PA-ACO mRNA accumulation was unaffected by 1-MCP. These results indicate positive feedback regulation of the PA-ACS1 gene and negative feedback regulation of the PA-ACS2 gene by ethylene, while PA-ACO exhibits positive feedback regulation by ethylene and is also induced by wounding. The hyper-induction of PA-ERS1 mRNA at relatively high concentrations of ethylene may be a mechanism of avocados to regulate the ethylene responsiveness of the tissues by dissipation of the gas.
AB - We investigated the differential regulation of two 1-aminocyclopropane-1-carboxylate synthase (ACS) genes, one 1-aminocyclopropane-1-carboxylate oxidase (ACO) gene and one ethylene response sensor (ERS1) ortholog during ripening and in response to wounding in avocados (Persea americana Mill. 'Bacon'). The 1-aminocyclopropane-1-carboxylate (ACC) content, ACS activity and detectable expression of PA-ACS1 mRNA increased and reached a maximum prior to the climacteric peak, whereas Ace activity and the PA-ACO mRNA levels increased markedly only at the upsurge of ripening ethylene. A basal level of PA-ERS1 transcript was detected as from harvest, however, PA-ERS1 transcript was hyper-induced at the climacteric peak of ethylene production. 1-Methylcyclopropene (1-MCP) application at thepreclimacteric and the onset of climacteric stages inhibited the ACS and ACO activities, the transcription of PA-ACS1 and suppressed PA-ACO and PA-ERS1 mRNAs to trace levels. Discontinuation of 1-MCP treatment led to super-induction of PA-ACS1, PA-ACO, and PA-ERS1 transcripts. Wound induced ethylene biosynthesis and woundinduced-induced PA-ACS2 mRNA accumulation were enhanced by 1-MCP, whereas wound-induced PA-ACO mRNA accumulation was unaffected by 1-MCP. These results indicate positive feedback regulation of the PA-ACS1 gene and negative feedback regulation of the PA-ACS2 gene by ethylene, while PA-ACO exhibits positive feedback regulation by ethylene and is also induced by wounding. The hyper-induction of PA-ERS1 mRNA at relatively high concentrations of ethylene may be a mechanism of avocados to regulate the ethylene responsiveness of the tissues by dissipation of the gas.
KW - 1-aminocyclopropane-1-carboxylate (ACC)
KW - Ethylene biosynthesis
KW - Ethylene response sensor 1 (ERS 1)
KW - Fruit ripening
KW - Gene expression
KW - Wounding
UR - http://www.scopus.com/inward/record.url?scp=0036275996&partnerID=8YFLogxK
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U2 - 10.21273/jashs.127.4.520
DO - 10.21273/jashs.127.4.520
M3 - Article
AN - SCOPUS:0036275996
VL - 127
SP - 520
EP - 527
JO - Journal of the American Society for Horticultural Science
JF - Journal of the American Society for Horticultural Science
SN - 0003-1062
IS - 4
ER -