Molecular and physiological evidence suggests the existence of a system II-like pathway of ethylene production in non-climacteric Citrus fruit
Molecular and physiological evidence suggests the existence of a system II-like pathway of ethylene production in non-climacteric Citrus fruit
复制标题
DOI：
10.1007/s00425-004-1228-3
复制
发表时间：
2004-06-01
期刊：
影响因子：
4.3
通讯作者：
Goldschmidt, EE
中科院分区：
文献类型：
--
作者：
Katz, E;Lagunes, PM;Goldschmidt, EE
成熟的柑橘类水果被归类为非更年期水果，在成熟过程中释放出非常少量的乙烯，但通过与成熟相关的色素变化和加速呼吸来对外源乙烯做出反应。在本研究中，我们发现附着在树上的年轻柑橘小果会产生高水平的乙烯，而乙烯在成熟过程中会急剧下降。收获后，小果表现出类似更年期的乙烯产量上升，随后诱导 1-氨基环丙烷-1-羧酸酯 (ACC) 合酶 1 (CsACS1)、ACC 氧化酶 1 (CsACO1) 和乙烯受体 CsERS1 基因。这种诱导通过外源乙烯或丙烯得以推进和增强，表明存在类似自催化系统 II 的乙烯生物合成。在成熟、分离的果实中，极低的乙烯产生率与 ACC 合酶 2 (CsACS2) 和乙烯受体 CsETR1 基因（系统 I）的组成型表达相关。即使在乙烯或丙烯处理后，CsACS1 基因表达在此阶段也检测不到，并且 CsERS1 基因表达保持恒定，表明没有发生自催化反应。幼果从类似系统 II 的行为向系统 I 行为的转变似乎受到发育控制。
Mature citrus fruits, which are classified as non-climacteric, evolve very low amounts of ethylene during ripening but respond to exogenous ethylene by ripening-related pigment changes and accelerated respiration. In the present study we show that young citrus fruitlets attached to the tree produce high levels of ethylene, which decrease dramatically towards maturation. Upon harvest, fruitlets exhibited a climacteric-like rise in ethylene production, preceded by induction of the genes for 1-aminocyclopropane-1-carboxylate (ACC) synthase 1 (CsACS1), ACC oxidase 1 (CsACO1) and the ethylene receptor CsERS1. This induction was advanced and augmented by exogenous ethylene or propylene, indicating an autocatalytic system II-like ethylene biosynthesis. In mature, detached fruit, very low rates of ethylene production were associated with constitutive expression of the ACC synthase 2 (CsACS2) and ethylene receptor CsETR1 genes (system I). CsACS1 gene expression was undetectable at this stage, even following ethylene or propylene treatment, and CsERS1 gene expression remained constant, indicating that no autocatalytic response had occurred. The transition from system II-like behavior of young fruitlets to system I behavior appears to be under developmental control.