据介绍，独脚金内酯（SL）是一类甲基丁烯酸内酯分子，由β-胡萝卜素经中间产物独脚金醇酸（CLA）衍生而来。经典SL作为信号物质作用于微生物和植物，而非经典SL主要充当植物激素。细胞色素P450 CYP722C催化了关键步骤，在大多数被子植物中将CLA转化为经典SL。
研究人员运用合成生物学手段，探究了CYP722C的演化前身CYP722A的功能。CYP722A将CLA转化为16-羟基-CLA（16-OH-CLA），这是一种非经典SL，仅在多种开花植物的地上部分检测到。对拟南芥中SL缺陷型突变体施加16-OH-CLA，可恢复其对地上部分分枝的调控，且16-OH-CLA可被SL信号通路识别。
总之，研究人员推测，CYP722A对16-OH-CLA的生物合成，是许多开花植物中介导根际信号传导的经典SL演化过程中的一个代谢关键环节。
附：英文原文
Title: Evolution of interorganismal strigolactone biosynthesis in seed plants
Author: Anqi Zhou, Annalise Kane, Sheng Wu, Kaibiao Wang, Michell Santiago, Yui Ishiguro, Kaori Yoneyama, Malathy Palayam, Nitzan Shabek, Xiaonan Xie, David C. Nelson, Yanran Li
Issue&Volume: 2025-01-17
Abstract: Strigolactones (SLs) are methylbutenolide molecules derived from β-carotene through an intermediate carlactonoic acid (CLA). Canonical SLs act as signals to microbes and plants, whereas noncanonical SLs are primarily plant hormones. The cytochrome P450 CYP722C catalyzes a critical step, converting CLA to canonical SLs in most angiosperms. Using synthetic biology, we investigated the function of CYP722A, an evolutionary predecessor of CYP722C. CYP722A converts CLA into 16-hydroxy-CLA (16-OH-CLA), a noncanonical SL detected exclusively in the shoots of various flowering plants. 16-OH-CLA application restores control of shoot branching to SL-deficient mutants in Arabidopsis thaliana and is perceived by the SL signaling pathway. We hypothesize that biosynthesis of 16-OH-CLA by CYP722A was a metabolic stepping stone in the evolution of canonical SLs that mediate rhizospheric signaling in many flowering plants.
DOI: adp0779
Source: https://www.science.org/doi/10.1126/science.adp0779