A cotton ascorbate peroxidase is involved in hydrogen peroxide homeostasis during fibre cell development
A cotton ascorbate peroxidase is involved in hydrogen peroxide homeostasis during fibre cell development
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DOI：
10.1111/j.1469-8137.2007.02120.x
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发表时间：
2007-01-01
期刊：
影响因子：
9.4
通讯作者：
Zhu, Yu-Xian
中科院分区：
文献类型：
--
作者：
Li, Hong-Bin;Qin, Yong-Mei;Zhu, Yu-Xian
活性氧（ROS）在细胞信号传导和应激反应等多种生理过程中发挥重要作用，而过氧化氢（H2O2）清除酶抗坏血酸过氧化物酶（APX）参与细胞内ROS水平的调节。本文通过蛋白质组学分析，鉴定了棉纤维伸长过程中细胞质APX1 （GhAPX1）的高度积累。GhAPX1 cDNA包含一个753的开放阅读框，通过编码250个氨基酸残基的蛋白质。当GhAPX1在大肠杆菌中表达时，纯化的GhAPX1是由两个相同亚基组成的二聚体，分子量为28 kDa。GhAPX1对抗坏血酸表现出最高的底物特异性。定量实时聚合酶链反应（PCR）分析显示，GhAPX1在野生型5 d后位纤维中高表达，而在无毛无毛突变体胚珠中的转录水平要低得多。用外源H2O2或乙烯处理离体培养的野生型棉花胚珠，诱导GhAPX1的表达，从而使APX总活性成比例增加，纤维细胞伸长延长。这些数据表明，GhAPX1的表达随着细胞H202和乙烯的增加而上调。GhAPX1编码一种功能酶，参与棉纤维发育过程中的过氧化氢稳态。
Reactive oxygen species (ROS) play important roles in multiple physiological processes such as cellular signalling and stress responses, whereas, the hydrogen peroxide (H2O2) scavenging enzyme ascorbate peroxidase (APX) participates in the regulation of intracellular ROS levels.Here, a cotton (Gossypium hirsutum) cytosolic APX1 (GhAPX1) was identified to be highly accumulated during cotton fibre elongation by proteomic analysis. GhAPX1 cDNA contained an open reading frame of 753-by encoding a protein of 250 amino acid residues. When GhAPX1 was expressed in Escherichia coli, the purified GhAPX1 was a dimer consisting of two identical subunits with a molecular mass of 28 kDa. GhAPX1 showed the highest substrate specificity for ascorbate. Quantitative real-time polymerase chain reaction (PCR) analyses showed that GhAPX1 was highly expressed in wild-type 5-d postanthesis fibres with much lower transcript levels in the fuzzless-lintless mutant ovules. Treating in vitro cultured wild-type cotton ovules with exogenous H2O2 or ethylene induced the expression of GhAPX1 and hence increased total APX activity proportionally, followed by extended fibre cell elongation. These data suggest that GhAPX1 expression is upregulated in response to an increase in cellular H202 and ethylene. GhAPX1 encodes a functional enzyme that is involved in hydrogen peroxide homeostasis during cotton fibre development.