Gene duplication in the diversification of secondary metabolism: Tandem 2-oxoglutarate-dependent dioxygenases control glucosinolate biosynthesis in arabidopsis
Gene duplication in the diversification of secondary metabolism: Tandem 2-oxoglutarate-dependent dioxygenases control glucosinolate biosynthesis in arabidopsis
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DOI：
10.1105/tpc.13.3.681
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发表时间：
2001-03-01
期刊：
影响因子：
11.6
通讯作者：
Mitchell-Olds, T
中科院分区：
文献类型：
--
作者：
Kliebenstein, DJ;Lambrix, VM;Mitchell-Olds, T
植物次生代谢物是一类在植物与环境相互作用中具有多种功能的化合物。次级代谢产物的巨大化学多样性无疑来自于负责其生物合成的同样多样的酶。然而，很少有人知道的进化酶参与次生代谢。我们正在研究拟南芥中芥子油苷（一大类次生代谢产物）的生物合成，以探讨参与次生代谢的酶的进化。拟南芥含有甲基亚磺酰基烷基、烯基和羟烷基芥子油苷存在的天然变异。在这篇文章中，我们报告的基因编码的2-酮戊二酸依赖性双加氧酶，负责这种变化的鉴定。这些基因，AOP2和AOP3，映射到染色体IV上的相同位置，由明显的基因复制引起，并控制甲基亚磺酰基烷基芥子油苷转化为烯基或羟烷基形式。通过异源表达在大肠杆菌和相关的基因表达模式的硫代葡萄糖苷表型，我们表明，AOP2催化甲基亚磺酰基烷基硫代葡萄糖苷转化为烯基硫代葡萄糖苷。相反，AOP3指导从甲基亚磺酰基烷基芥子油苷形成羟烷基芥子油苷。没有生态型共表达这两个基因。此外，功能性AOP2和AOP3的缺乏导致前体甲基亚磺酰基烷基芥子油苷的积累。这个基因家族的第三个成员，AOP1，存在于至少两种形式，并发现在所有的生态型检查。然而，其催化作用仍不确定。
Secondary metabolites are a diverse set of plant compounds believed to have numerous functions in plant-environment interactions. The large chemical diversity of secondary metabolites undoubtedly arises from an equally diverse set of enzymes responsible for their biosynthesis. However, little is known about the evolution of enzymes involved in secondary metabolism. We are studying the biosynthesis of glucosinolates, a large group of secondary metabolites, in Arabidopsis to investigate the evolution of enzymes involved in secondary metabolism. Arabidopsis contains natural variations in the presence of methylsulfinylalkyl, alkenyl, and hydroxyalkyl glucosinolates. In this article, we report the identification of genes encoding two 2-oxoglutarate-dependent dioxygenases that are responsible for this variation. These genes, AOP2 and AOP3, which map to the same position on chromosome IV, result from an apparent gene duplication and control the conversion of methylsulfinylalkyl glucosinolate to either the alkenyl or the hydroxyalkyl form. By heterologous expression in Escherichia and the correlation of gene expression patterns to the glucosinolate phenotype, we show that AOP2 catalyzes the conversion of methylsulfinylalkyl glucosinolates to alkenyl glucosinolates. Conversely, AOP3 directs the formation of hydroxyalkyl glucosinolates from methylsulfinylalkyl glucosinolates. No ecotype coexpressed both genes. Furthermore, the absence of functional AOP2 and AOP3 leads to the accumulation of the precursor methylsulfinylalkyl glucosinolates. A third member of this gene family, AOP1, is present in at least two forms and found in all ecotypes examined. However, its catalytic role is still uncertain.