Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Suite G01, Memphis TN 38163, USA.
Plant J. 2011 Apr;66(1):194-211. doi: 10.1111/j.1365-313X.2011.04529.x.
Being by far the largest family of enzymes to support plant metabolism, the cytochrome P450s (CYPs) constitute an excellent reporter of metabolism architecture and evolution. The huge superfamily of CYPs found in angiosperms is built on the successful evolution of 11 ancestral genes, with very different fates and progenies. Essential functions in the production of structural components (membrane sterols), light harvesting (carotenoids) or hormone biosynthesis kept some of them under purifying selection, limiting duplication and sub/neofunctionalization. One group (the CYP71 clan) after an early trigger to diversification, has kept growing, producing bursts of gene duplications at an accelerated rate. The CYP71 clan now represents more than half of all CYPs in higher plants. Such bursts of gene duplication are likely to contribute to adaptation to specific niches and to speciation. They also occur, although with lower frequency, in gene families under purifying selection. The CYP complement (CYPomes) of rice and the model grass weed Brachypodium distachyon have been compared to view evolution in a narrower time window. The results show that evolution of new functions in plant metabolism is a very long-term process. Comparative analysis of the plant CYPomes provides information on the successive steps required for the evolution of land plants, and points to several cases of convergent evolution in plant metabolism. It constitutes a very useful tool for spotting essential functions in plant metabolism and to guide investigations on gene function.
作为支持植物代谢的最大酶家族，细胞色素 P450 （CYPs）是代谢结构和进化的极好报告者。被子植物中发现的庞大 CYP 超家族是在 11 个祖先基因成功进化的基础上构建的，这些基因具有非常不同的命运和后代。在结构成分（膜甾醇）、光捕获（类胡萝卜素）或激素生物合成中的重要功能使其中一些基因受到纯化选择的限制，限制了重复和亚/新功能化。一组（CYP71 家族）在早期多样化的触发后，一直保持着增长，以加速的速度产生基因重复的爆发。CYP71 家族现在代表了高等植物中一半以上的所有 CYP。这种基因重复的爆发可能有助于适应特定的生态位和物种形成。尽管频率较低，但在受到纯化选择的基因家族中也会发生这种情况。对水稻和模式草杂草拟南芥的 CYP 补充（CYPomes）进行了比较，以在更窄的时间窗口内观察进化。结果表明，植物代谢中新功能的进化是一个非常长期的过程。对植物 CYPomes 的比较分析提供了有关陆地植物进化所需的连续步骤的信息，并指出了植物代谢中几个趋同进化的案例。它是发现植物代谢中必需功能的非常有用的工具，并指导基因功能的研究。
