Ethylene in induced conifer defense: cDNA cloning, protein expression, and cellular and subcellular localization of 1-aminocyclopropane-1-carboxylate oxidase in resin duct and phenolic parenchyma cells
Ethylene in induced conifer defense: cDNA cloning, protein expression, and cellular and subcellular localization of 1-aminocyclopropane-1-carboxylate oxidase in resin duct and phenolic parenchyma cells
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DOI：
10.1007/s00425-006-0274-4
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发表时间：
2006-09-01
期刊：
影响因子：
4.3
通讯作者：
Bohlmann, Jorg
中科院分区：
文献类型：
--
作者：
Hudgins, J. W.;Ralph, Steven G.;Bohlmann, Jorg
松科的成员有复杂的化学防御策略。针叶树防御与专门的细胞类型的树皮涉及组成型和诱导型积累的酚类化合物的多酚韧皮薄壁细胞和树脂导管中的油性树脂萜类化合物。这些防御措施可以保护树木免受昆虫植食性和真菌定植。植物激素乙烯已显示诱导在道格拉斯冷杉（花旗松）茎中昆虫进食、机械创伤或真菌接种后发生的相同解剖学和细胞防御反应（Hudgins和Franceschi in Plant Physiol 135：2134-2149，2004）。然而，人们对针叶树防御中参与乙烯形成的基因及其蛋白质表达的时间和空间模式知之甚少。1-氨基环丙烷-1-羧酸氧化酶（ACO）催化乙烯生物合成的最后一步。我们从三种针叶树物种，锡特卡云杉（Picea sitchensis），白色云杉（P. glauca），和道格拉斯冷杉，克隆全长和近全长ACO cDNA，每个与拟南芥ACO蛋白高度相似。使用拟南芥抗ACO抗体，我们确定ACO是组成型表达在道格拉斯冷杉干组织和上调机械创伤，与创伤诱导的乙烯水平的增加一致。免疫定位显示，胞质ACO主要存在于专门的细胞类型的伤口诱导树皮，特别是在上皮细胞的萜类化合物生产皮层树脂导管，多酚韧皮部薄壁细胞，射线薄壁细胞。
Members of the Pinaceae family have complex chemical defense strategies. Conifer defenses associated with specialized cell types of the bark involve constitutive and inducible accumulation of phenolic compounds in polyphenolic phloem parenchyma cells and oleoresin terpenoids in resin ducts. These defenses can protect trees against insect herbivory and fungal colonization. The phytohormone ethylene has been shown to induce the same anatomical and cellular defense responses that occur following insect feeding, mechanical wounding, or fungal inoculation in Douglas fir (Pseudotsuga menziesii) stems (Hudgins and Franceschi in Plant Physiol 135:2134-2149, 2004). However, very little is known about the genes involved in ethylene formation in conifer defense or about the temporal and spatial patterns of their protein expression. The enzyme 1-aminocyclopropane-1-carboxylate oxidase (ACO) catalyzes the final step in ethylene biosynthesis. We cloned full-length and near full-length ACO cDNAs from three conifer species, Sitka spruce (Picea sitchensis), white spruce (P. glauca), and Douglas fir, each with high similarity to Arabidopsis thaliana ACO proteins. Using an Arabidopsis anti-ACO antibody we determined that ACO is constitutively expressed in Douglas fir stem tissues and is up-regulated by mechanical wounding, consistent with the wound-induced increase of ethylene levels. Immunolocalization showed cytosolic ACO is predominantly present in specialized cell types of the wound-induced bark, specifically in epithelial cells of terpenoid-producing cortical resin ducts, in polyphenolic phloem parenchyma cells, and in ray parenchyma cells.