Differential regulation of genes encoding ethylene biosynthesis enzymes and ethylene response sensor ortholog during ripening and in response to wounding in avocados
Differential regulation of genes encoding ethylene biosynthesis enzymes and ethylene response sensor ortholog during ripening and in response to wounding in avocados
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DOI：
10.21273/jashs.127.4.520
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发表时间：
2002-07-01
影响因子：
1.9
通讯作者：
Inaba, A
中科院分区：
文献类型：
--
作者：
Owino, WO;Nakano, R;Inaba, A
我们研究了牛油果（Persea americana Mill.‘Bacon’）在成熟过程中以及对受伤的反应中两种 1-氨基环丙烷-1-羧酸合酶 (ACS) 基因、一种 1-氨基环丙烷-1-羧酸氧化酶 (ACO) 基因和一种乙烯反应传感器 (ERS1) 直向同源物的差异调节。 1-氨基环丙烷-1-甲酸酯(ACC)含量、ACS活性和PA-ACS1 mRNA的可检测表达增加并在更年期峰值之前达到最大值，而ACO活性和PA-ACO mRNA水平仅在成熟乙烯激增时显着增加。从收获时检测到 PA-ERS1 转录本的基础水平，然而，PA-ERS1 转录本在乙烯产生的更年期峰值被过度诱导。在更年期前期和更年期开始时应用 I-甲基环丙烯 (1-MCP) 可抑制 ACS 和 ACO 活性、PA-ACS1 转录，并将 PA-ACO 和 PA-ERS1 mRNA 抑制至微量水平。停止 1-MCP 治疗会导致 PA-ACS1、PA-ACO 和 PA-ERS1 转录物的过度诱导。 1-MCP 增强了伤口诱导的乙烯生物合成和伤口诱导的 PA-ACS2 mRNA 积累，而伤口诱导的 PA-ACO mRNA 积累不受 1-MCP 影响。这些结果表明乙烯对PA-ACS1基因的正反馈调节和PA-ACS2基因的负反馈调节，而PA-ACO表现出乙烯的正反馈调节并且也由受伤诱导。 PA-ERS1 mRNA 在相对高浓度的乙烯下的过度诱导可能是鳄梨通过气体消散来调节组织乙烯反应性的机制。
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 ACO 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. I-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 wound-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.