Terpenoid-based defenses in conifers:: cDNA cloning, characterization, and functional expression of wound-inducible (E)-α-bisabolene synthase from grand fir (Abies grandis)
Terpenoid-based defenses in conifers:: cDNA cloning, characterization, and functional expression of wound-inducible (E)-α-bisabolene synthase from grand fir (Abies grandis)
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DOI：
10.1073/pnas.95.12.6756
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发表时间：
1998-06-09
影响因子：
11.1
通讯作者：
Croteau, R
中科院分区：
文献类型：
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作者：
Bohlmann, J;Crock, J;Croteau, R
（E）-α-红没药烯合酶是大冷杉（Abies grandis）的两种创伤诱导型倍半萜烯脱氢酶之一，并且该环化反应的烯烃产物被认为是冷杉属物种中的Todomatuic酸、保幼酮和相关昆虫保幼激素模拟物的前体。通过基于PCR的策略从创伤诱导的大冷杉茎文库中分离编码（E）-α-红没药烯合酶的cDNA，并在大肠杆菌中功能性表达，并显示产生（E）-α-红没药烯作为法呢基二磷酸的唯一产物。所表达的合酶的推导大小为93.8 kDa，pI为5.03，表现出倍半萜烯脱氢酶的其他典型性质，并且在序列上类似于其他萜类脱氢酶，除了一个大的氨基末端插入，对应于Pro（81）-瓦尔（296）。生物合成制备的（E）-α-[H-3]红没药烯在诱导的大冷杉细胞中转化为Todomatuic酸，并且红没药烯合酶mRNA出现的时间过程通过北方杂交显示滞后于负责诱导的油性树脂单萜类产生的mRNA。这些结果表明，诱导的（E）-α-红没药烯生物合成的防御反应的一部分，针对昆虫食草动物，添加可能的真菌病原体，这是从诱导的油树脂单萜生产不同。
(E)-alpha-Bisabolene synthase is one of two wound-inducible sesquiterpene synthases of grand fir (Abies grandis), and the olefin product of this cyclization reaction is considered to be the precursor in Abies species of todomatuic acid, juvabione, and related insect juvenile hormone mimics. A cDNA encoding (E)-alpha-bisabolene synthase was isolated from a wound-induced-grand fir stem library by a PCR-based strategy and was functionally expressed in Escherichia coli and shown to produce (E)-alpha-bisabolene as the sole product from farnesyl diphosphate. The expressed synthase has a deduced size of 93.8 kDa and a pI of 5.03, exhibits other properties typical of sesquiterpene synthases, and resembles in sequence other terpenoid synthases with the exception of a large aminoterminal insertion, corresponding to Pro(81)-Val(296). Biosynthetically prepared (E)-alpha-[H-3]bisabolene was converted to todomatuic acid in induced grand fir cells, and the time course of appearance of bisabolene synthase mRNA was shown by Northern hybridization to lag behind that of mRNAs responsible for production of induced oleoresin monoterpenes. These results suggest that induced (E)-alpha-bisabolene biosynthesis constitutes part of a defense response targeted to insect herbivores, add possibly fungal pathogens, that is distinct from induced oleoresin monoterpene production.