An investigation of the storage and biosynthesis of phenylpropenes in sweet basil
An investigation of the storage and biosynthesis of phenylpropenes in sweet basil
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DOI：
10.1104/pp.125.2.539
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发表时间：
2001-02-01
期刊：
影响因子：
7.4
通讯作者：
Pichersky, E
中科院分区：
文献类型：
--
作者：
Gang, DR;Wang, JH;Pichersky, E
含有高浓度的苯丙烯类防御化合物（丁香酚、胡椒酚及其衍生物）的植物自古以来就被认为是人类消费的重要香料（例如丁香），并且具有高经济价值。然而，我们对植物中产生这些化合物的生物合成途径的理解仍然不完整。几种罗勒（罗勒）生产的挥发油基本上只含有一种或两种特定的苯丙烯化合物。像唇形科的其他成员一样，罗勒叶在其表面上具有两种类型的腺毛，称为盾形腺和头状腺。我们在这里证明，挥发油成分丁香酚和甲基chavicol积累，分别在盾形腺体的罗勒线SW（基本上只产生丁香酚）和EMX-1（基本上只产生甲基chavicol）。在导致这些苯丙烯类化合物的生物合成途径中，对推定的酶的测定将许多相应的酶活性几乎完全定位于活跃产生挥发油的叶片中的盾形腺。从叶盾状腺的表达序列标签数据库的分析表明，已知的苯丙烷途径的基因在这些结构中表达水平非常高，占总表达序列标签的13%。另外14%的cDNA编码用于S-腺苷甲硫氨酸生物合成的酶，S-腺苷甲硫氨酸是许多苯丙烯合成的重要底物。因此，罗勒的盾形腺似乎是合成和储存苯丙烯的高度专门化的结构，并作为一个很好的模型系统来研究苯丙烯的生物合成。
Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.