Regulation of simultaneous synthesis of floral scent terpenoids by the 1,8-cineole synthase of Nicotiana suaveolens
Regulation of simultaneous synthesis of floral scent terpenoids by the 1,8-cineole synthase of Nicotiana suaveolens
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DOI：
10.1007/s11103-007-9202-7
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发表时间：
2007-07
影响因子：
5.1
通讯作者：
Susanna Roeder;Anna-Maria Hartmann;U. Effmert;B. Piechulla
中科院分区：
文献类型：
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作者：
Susanna Roeder;Anna-Maria Hartmann;U. Effmert;B. Piechulla
N的白色花朵。 suaveolense 散发出复杂的芳香挥发物香味。主要化合物是苯类化合物（例如苯甲酸甲酯、水杨酸甲酯、苯甲酸苄酯和水杨酸苄酯）、单萜（1,8-桉叶素、柠檬烯、桧烯、E-β-罗勒烯、β-β-月桂烯、α-和β-蒎烯和α-萜品醇）和倍半萜烯（例如 石竹烯），这些物质在夜间排放量都较高。在这里，我们表明大多数单萜的同时夜间排放是通过单一花特异性多产物酶（1,8-桉树脑合酶，CIN）实现的，该酶合成“桉树脑盒”的单萜。有趣的是，N. suaveolensis 是 Suaveolentes 科中唯一已知的分类单元，其花朵发出“单萜桉叶素盒”，这在 Alatae 科中是典型的。 CIN 的基因序列分析揭示了与来自葡萄、栎属冬青、柑橘和 C 的其他被子植物单萜合酶的最高相似性。 limon，它们聚集在萜烯合酶 B 亚家族的同一分支中。然而，基于其合成产品，N. suaveolensCIN 与拟南芥根和丹参叶的酶具有相似性。然后。 suaveolensCIN 基因仅在柱头/花柱组织和花瓣中表达。花瓣的薄切片主要在近轴和远轴表皮中存在酶；这有利于挥发物在各个空间方向的全面排放。单萜排放的振荡是生物钟调节 CIN 基因的结果，振荡发生在转录物和蛋白质积累以及酶活性水平。亮/暗或暗/亮转换信号同步缓慢运行的内源时钟。 N 建立了两种同步气味发射策略。 suaveolensflowers：（i）通过多产物酶合成挥发性有机化合物，以及（ii）通过生物钟协调生物合成途径。
The white flowers ofN. suaveolensemit a complex bouquet of fragrance volatiles. The dominant compounds are benzenoids (e.g. methyl benzoate, methyl salicylate, benzyl benzoate and benzyl salicylate), monoterpenes (1,8-cineole, limonene, sabinene,E-β-ocimene, β-β-myrcene, α- and β-pinene and α-terpineole) and sesquiterpenes (e.g. caryophyllene), which are all emitted at higher levels during the night. Here, we show that the simultaneous nocturnal emission of most monoterpenes is realized by a single floral-specific multi-product enzyme (1,8-cineole synthase, CIN), which synthesizes the monoterpenes of the “cineole cassette”. Interestingly,N. suaveolensis the only known taxon of the Suaveolentes section to have a flower emitting “cineole cassette of monoterpenes” which is otherwise typical for the Alatae section. Gene sequence analysis of CIN has revealed the highest similarities to other angiosperm monoterpene synthases fromVitis vinifera,Quercus ilex,Citrus unshiuandC. limon, which cluster in the same branch of the terpene synthase B subfamily. However, based on its synthesized products,N. suaveolensCIN shares similarity with enzymes of theArabidopsis thalianaroot andSalvia officinalisleaf. TheN. suaveolensCIN gene is only expressed in the stigma/style tissue and petals. Thin sections of petals present the enzyme primarily in the adaxial and abaxial epidermis; this facilitates the comprehensive emission of volatiles in all spacial directions. The oscillation of monoterpene emission is a consequence of the regulation of the CIN gene by the circadian clock, with oscillations occurring at the level of transcript and protein accumulations and of enzyme activity. Light/dark or dark/light transition signals synchronize the slow-running endogenous clock. Two strategies for synchronized scent emission have been established inN. suaveolensflowers: (i) the synthesis of volatile organic compounds by a multi-product enzyme and (ii) the coordination of biosynthetic pathways by a circadian clock.