Lineage-specific gene radiations underlie the evolution of novel betalain pigmentation in Caryophyllales.
Lineage-specific gene radiations underlie the evolution of novel betalain pigmentation in Caryophyllales.
复制标题
DOI：
10.1111/nph.13441
复制
发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Smith SA
中科院分区：
文献类型：
--
作者：
Brockington SF;Yang Y;Gandia-Herrero F;Covshoff S;Hibberd JM;Sage RF;Wong GK;Moore MJ;Smith SA
甜菜素是石竹属植物特有的色素，在结构和生物合成上与花青素不同。目前已经确定了betalamic合成途径中的两个关键酶：催化betalamic酸形成的4,5-双加氧酶（DODA）和催化环dopa形成的细胞色素P450基因CYP76AD1。我们进行了系统发育分析，揭示了DODA和CYP76AD1谱系的进化历史，并在色素状态祖先重建的背景下，我们探索了这些基因的进化与石竹属植物色素复杂进化的关系。CYP76AD1和DODA谱系内的重复出现在核心石竹中β素色素沉着的起源之前。重复产生了β蛋白合成特异性的DODA-α和CYP76AD1-α亚型。这两种β素特异性异构体随后在花青素科和石竹科中丢失或下调。我们的研究结果表明β蛋白合成途径的单一起源，在CYP76AD1和DODA谱系中基因复制后产生新功能。花青素类群中DODA-α和CYP76AD1-α的缺失表明，紫杉属植物中甜菜色素色素的缺失是通过基因缺失或下调介导的。【2015年5月13日在线发布后补充的更正：在摘要的最后两段中，基因名称CYP761A更改为CYP76AD1。】
Betalain pigments are unique to the Caryophyllales and structurally and biosynthetically distinct from anthocyanins. Two key enzymes within the betalain synthesis pathway have been identified: 4,5-dioxygenase (DODA) that catalyzes the formation of betalamic acid and CYP76AD1, a cytochrome P450 gene that catalyzes the formation of cyclo-DOPA. We performed phylogenetic analyses to reveal the evolutionary history of the DODA and CYP76AD1 lineages and in the context of an ancestral reconstruction of pigment states we explored the evolution of these genes in relation to the complex evolution of pigments in Caryophylalles. Duplications within the CYP76AD1 and DODA lineages arose just before the origin of betalain pigmentation in the core Caryophyllales. The duplications gave rise to DODA-α and CYP76AD1-α isoforms that appear specific to betalain synthesis. Both betalain-specific isoforms were then lost or downregulated in the anthocyanic Molluginaceae and Caryophyllaceae. Our findings suggest a single origin of the betalain synthesis pathway, with neofunctionalization following gene duplications in the CYP76AD1 and DODA lineages. Loss of DODA-α and CYP76AD1-α in anthocyanic taxa suggests that betalain pigmentation has been lost twice in Caryophyllales, and exclusion of betalain pigments from anthocyanic taxa is mediated through gene loss or downregulation. [Correction added after online publication 13 May 2015: in the last two paragraphs of the Summary the gene name CYP761A was changed to CYP76AD1.]