Polyamine oxidase, a hydrogen peroxide-producing enzyme, is up-regulated by light and down-regulated by auxin in the outer tissues of the maize mesocotyl
Polyamine oxidase, a hydrogen peroxide-producing enzyme, is up-regulated by light and down-regulated by auxin in the outer tissues of the maize mesocotyl
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DOI：
10.1104/pp.011379
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发表时间：
2003-02-01
期刊：
影响因子：
7.4
通讯作者：
Angelini, R
中科院分区：
文献类型：
--
作者：
Cona, A;Cenci, F;Angelini, R
外源生长素（1-萘乙酸）抑制玉米（Zea mays）中胚轴外部组织中多胺氧化酶（PAO）（一种产生过氧化氢的酶）光诱导的活性增加。同样的现象也发生在 PAO 蛋白和 mRNA 积累水平上。无论是在黑暗中还是在光照后，壁结合的 PAO 活性与可提取的 PAO 活性比率均不受生长素处理的影响。乙烯处理不影响 PAO 活性，因此排除了生长素通过增加乙烯生物合成而产生的影响。光处理后，生长素极性运输抑制剂N-1-萘基邻苯二甲酸或2,3,5-三碘苯甲酸导致外部组织中PAO表达进一步增加。 PAO 表达的小幅增加通常发生在植物在黑暗中发育过程中的中胚轴表皮中，也受到生长素的抑制，尽管相对于光暴露的组织而言程度较小，并且受到 N-1-萘基邻苯二甲酸或 2,3,5-三碘苯甲酸的刺激，因此表明 PAO 表达的复杂调节。表皮细胞的免疫金超微结构分析揭示了 PAO 与分泌途径和细胞壁的关联。该组织细胞壁中酶的存在因光处理而大大增加。与生长素对光诱导的 PAO 表达的影响一致，激素处理抑制了原浆内和细胞壁中免疫金染色的增加。这些结果表明，在光诱导的玉米中胚轴表皮组织细胞壁分化过程中，光和生长素均可微调 PAO 的表达。
Exogenously supplied auxin (1-naphthaleneacetic acid) inhibited light-induced activity increase of polyamine oxidase (PAO), a hydrogen peroxide-producing enzyme, in the outer tissues of maize (Zea mays) mesocotyl. The same phenomenon operates at PAO protein and mRNA accumulation levels. The wall-bound to extractable PAO activity ratio was unaffected by auxin treatment, either in the dark or after light exposure. Ethylene treatment did not affect PAO activity, thus excluding an effect of auxin via increased ethylene biosynthesis. The auxin polar transport inhibitors N-1-naphthylphthalamic acid or 2,3,5-triiodobenzoic acid caused a further increase of PAO expression in outer tissues after light treatment. The small increase of PAO expression, normally occurring in the mesocotyl epidermis during plant development in the dark, was also inhibited by auxin, although to a lesser extent with respect to light-exposed tissue, and was stimulated by N-1-naphthylphthalamic acid or 2,3,5-triiodobenzoic acid, thus suggesting a complex regulation of PAO expression. Immunogold ultrastructural analysis in epidermal cells revealed the association of PAO with the secretory pathway and the cell walls. The presence of the enzyme in the cell walls of this tissue greatly increased in response to light treatment. Consistent with auxin effects on light-induced PAO expression, the hormone treatment inhibited the increase in immunogold staining both intraprotoplasmically and in the cell wall. These results suggest that both light and auxin finely tune PAO expression during the light-induced differentiation of the cell wall in the maize mesocotyl epidermal tissues.