Cloning and characterization of an allene oxide cyclase, PpAOC3, in Physcomitrella patens
Cloning and characterization of an allene oxide cyclase, PpAOC3, in Physcomitrella patens
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DOI：
10.1007/s10725-011-9592-z
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发表时间：
2011-11-01
影响因子：
4.2
通讯作者：
Nabeta, Kensuke
中科院分区：
文献类型：
--
作者：
Hashimoto, Takahiro;Takahashi, Kosaku;Nabeta, Kensuke
氧化丙二烯环化酶 (AOC) 是开花植物十八烷类途径中合成 12-氧代植物二烯酸 (OPDA) 的关键酶，OPDA 是信号分子茉莉酸 (JA) 的生物合成前体。对小立碗藓基因组的数据库搜索揭示了 AOC 基因的存在，该基因与之前报道的两个 AOC 基因 PpAOC1 和 PpAOC2 不同。克隆鉴定出的 AOC 基因（命名为 PpAOC3）后，获得的 cDNA 序列（897 bp）比数据库中预测的 AOC 基因（765 bp）大，因为推测的内含子未完全删除。尽管 PpAOC3 与其他物种的 AOC 蛋白没有表现出高度相似性，但重组 PpAOC3 表现出 AOC 活性并易位至叶绿体，正如在其他 AOC 蛋白中观察到的那样。值得注意的是，PpAOC3 的表达谱与其他 PpAOC 不同，因为它在原丝体中的表达高于配子体中的表达。尽管 OPDA 和 JA 等 oxylipin 在 P. patens 中的功能仍然难以捉摸，但十八烷通路中酶的进一步表征以及 oxylipin 的作用将有助于阐明该模型苔藓植物中的生理过程。
Allene oxide cyclase (AOC) is a key enzyme in the octadecanoid pathway of flowering plants that synthesizes 12-oxo-phytodienoic acid (OPDA), which is a biosynthetic precursor of the signal molecule jasmonic acid (JA). A database search of the Physcomitrella patens genome revealed the presence of an AOC gene unique from the two previously reported AOC genes, PpAOC1 and PpAOC2. After cloning the identified AOC gene, designated PpAOC3, the obtained cDNA sequence (897 bp) was larger than the predicted AOC gene (765 bp) in the database because a speculated intron was not fully deleted. Although PpAOC3 did not display high similarity with AOC proteins from other species, recombinant PpAOC3 exhibited AOC activity and translocated to chloroplasts, as is observed for other AOC proteins. Notably, the expression profile of PpAOC3 differed from the other PpAOCs, as its expression in protonemata was higher than that in gametophores. Although the function of oxylipins such as OPDA and JA remains elusive in P. patens, further characterization of the enzymes in the octadecanoid pathway and the role of oxylipin will aid in the elucidation of physiological processes in this model bryophyte.