Key Laboratory of Chemical Biology of Natural Products, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China.
Biology Department, Brookhaven National Laboratory, Upton, New York 11973.
Plant Physiol. 2020 Dec;184(4):1731-1743. doi: 10.1104/pp.20.01185. Epub 2020 Oct 6.
During the course of evolution of land plants, different classes of flavonoids, including flavonols and anthocyanins, sequentially emerged, facilitating adaptation to the harsh terrestrial environment. Flavanone 3β-hydroxylase (F3H), an enzyme functioning in flavonol and anthocyanin biosynthesis and a member of the 2-oxoglutarate-dependent dioxygenase (2-ODD) family, catalyzes the hydroxylation of ()-flavanones to dihydroflavonols, but its origin and evolution remain elusive. Here, we demonstrate that functional flavone synthase Is (FNS Is) are widely distributed in the primitive land plants liverworts and evolutionarily connected to seed plant F3Hs. We identified and characterized a set of 2-ODD enzymes from several liverwort species and plants in various evolutionary clades of the plant kingdom. The bifunctional enzyme FNS I/F2H emerged in liverworts, and FNS I/F3H evolved in () and , suggesting that they represent the functional transition forms between canonical FNS Is and F3Hs. The functional transition from FNS Is to F3Hs provides a molecular basis for the chemical evolution of flavones to flavonols and anthocyanins, which contributes to the acquisition of a broader spectrum of flavonoids in seed plants and facilitates their adaptation to the terrestrial ecosystem.
在陆生植物的进化过程中，不同类别的类黄酮（包括黄酮醇和花青素）依次出现，促进了植物对恶劣陆地环境的适应。黄酮醇 3β-羟化酶（F3H）是一种参与黄酮醇和花青素生物合成的酶，属于 2-氧戊二酸依赖性双加氧酶（2-ODD）家族，它能催化（）-黄烷酮羟化为二氢黄酮醇，但它的起源和进化仍然难以捉摸。在这里，我们证明了功能黄酮合酶（FNS Is）广泛分布于原始的陆生植物——苔类植物中，并且与种子植物 F3H 具有进化上的联系。我们从几个苔类物种和植物王国各个进化分支中鉴定并鉴定了一组 2-ODD 酶。双功能酶 FNS I/F2H 出现在苔类植物中，FNS I/F3H 则出现在 和 中，这表明它们代表了典型的 FNS Is 和 F3Hs 之间的功能过渡形式。FNS Is 向 F3Hs 的功能转变为类黄酮向黄酮醇和花青素的化学进化提供了分子基础，这有助于种子植物获得更广泛的类黄酮谱，并促进它们对陆地生态系统的适应。
