Stepwise evolution of floral pigmentation predicted by biochemical pathway structure
Stepwise evolution of floral pigmentation predicted by biochemical pathway structure
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DOI：
10.1111/evo.13589
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发表时间：
2018-12-01
期刊：
影响因子：
3.3
通讯作者：
Smith, Stacey D.
中科院分区：
文献类型：
--
作者：
Ng, Julienne;Freitas, Loreta B.;Smith, Stacey D.
发育途径在影响自然发生表型的分布方面起着重要作用。例如，通路结构和调节可能使某些表型不可接近或限制表型进化的途径。在这项研究中，我们研究了整个茄科花色素苷色素，并测试表型变异的模式是否与预测的限制黄酮类化合物生物合成途径的结构的基础上一致。我们发现，花色素苷的演变发生在一个逐步的方式，其中红色单羟基化天竺葵色素和蓝色三羟基化飞燕草色素的生产之间的过渡首先通过一个中间步骤，生产紫色二羟基化花青素色素。虽然这三种色素类型之间的转换频率不同，我们推断，这些变化往往是可逆的，这表明基本的生化途径的功能通常是保守的。此外，我们的研究发现，一些色素组合从未被观察到，这表明了对自然发生的表型的额外限制。总的来说，我们的研究结果提供了深入了解被子植物全生物化学途径的结构如何塑造花色素沉着的宏观进化变化。
Developmental pathways play a major role in influencing the distribution of naturally occurring phenotypes. For example, pathway structure and regulation could make some phenotypes inaccessible or restrict the routes through which phenotypes evolve. In this study, we examine floral anthocyanin pigments across the Solanaceae family and test whether patterns of phenotypic variation are consistent with predicted constraints based on the structure of the flavonoid biosynthetic pathway. We find that anthocyanin evolution occurs in a stepwise manner whereby transitions between the production of red mono hydroxylated pelargonidin pigments and blue trihydroxylated delphinidin pigments first passes through an intermediate step of producing purple dihydroxylated cyanidin pigments. Although the transitions between these three pigment types differ in frequency, we infer that these shifts are often reversible, suggesting that the functionality of the underlying biochemical pathway is generally conserved. Furthermore, our study finds that some pigment combinations are never observed, pointing to additional constraints on naturally occurring phenotypes. Overall, our findings provide insights into how the structure of an angiosperm-wide biochemical pathway has shaped macroevolutionary variation in floral pigmentation.