Peeling off the secrets of Populus trichocarpa defences

植物特化代谢物（传统上称为次生代谢物）是一类生物合成局限于特定谱系，在生态相互作用中起关键作用的化合物。当环境发生变化时，植物获得了合成新的专门代谢物的能力，作为应对生物和非生物胁迫的一种策略。我的研究计划的长期愿景是通过探索特殊代谢物的自然多样性来理解这种生化反应，弄清楚新的代谢物是如何合成的，并最终破译它们如何帮助植物在具有挑战性的环境中茁壮成长。我提出的NSERC研究计划侧重于黑棉树（Populus trichocarpa，杨树）的蜡和萜烯作为模型系统。在植物用来阻止入侵者的特征中，角质层和角质层内的蜡质构成了抵御恶劣环境的第一道屏障。为了研究表皮蜡质和单个蜡质成分的作用，我们将利用蜡质成分和丰度的广泛变化，存在于一组自然发生的毛霉基因型中。我们已经证明，烯烃是一种有机化合物，是黑棉叶蜡的主要成分。有趣的是，尽管烯烃在工业上有许多用途，但工厂生产烯烃的方式却完全不为人所知。我之前的工作发现了第一种参与烯烃生物合成的酶。这一发现为研究角质层蜡质生物合成的新途径打开了大门。然而，如果我们想利用表皮蜡质多样性作为对抗环境胁迫的保护机制，仍有几个关键领域需要研究。在拟议的研究中，我们将解决以下短期目标：1-识别和表征参与调节和产生烯烃的基因；2-研究表皮蜡质对环境胁迫的作用；3-开发研究萜烯所需的工具和方法，萜烯是黑棉树的另一组防御化合物。尽管推动我研究的根本问题是植物为什么会合成专门的代谢物，但由此产生的知识在作物改良和工业方面具有潜在的应用价值。通过了解特定代谢物的生物合成和生态作用，我们将能够培育或设计更好地适应特定环境的植物。此外，蜡和萜烯作为药品、杀虫剂、食品添加剂和生物燃料具有商业价值。该计划将需要一个多学科的方法，将培养高素质的人才在基因组学，生物化学，分析化学，植物生理学和生物技术。

Plant specialized metabolites (traditionally called secondary metabolites) are compounds whose biosynthesis is restricted to specific lineages and play key roles in ecological interactions. Plants acquire the ability to synthesize new specialized metabolites as a strategy to cope with biotic and abiotic stress when the environment changes. The long-term vision of my research program is to understand this biochemical response by exploring the natural diversity of specialized metabolites, figuring out how new metabolites are synthesized, and ultimately deciphering how they help the plant thrive in a challenging environment. My proposed NSERC research program focuses on waxes and terpenes from the black cottonwood tree (Populus trichocarpa, poplar) as model systems. Among the traits that plants use to deter invaders, the cuticle and the waxes contained within the cuticle constitute the first barrier against a hostile environment. To investigate the role of the cuticular waxes and individual wax components, we will exploit the extensive variation in wax composition and abundance present in a collection of naturally occurring genotypes of P. trichocarpa. We have shown that alkenes, a type of organic compound, are major components of the wax of black cottonwood leaves. Interestingly, despite the many industrial uses of alkenes, the way by which they are produced in plants was completely unknown. My previous work identified the first enzyme involved in the biosynthesis of alkenes. This discovery has opened the doors to the study of a new pathway for the biosynthesis of cuticular waxes. However, there are still several key areas that need to be investigated if we want to harness cuticular wax diversity as a protection mechanism against environmental stress. In the proposed research we will address the following short-term objectives: 1- Identify and characterize the genes involved in regulating and producing alkenes; 2- Investigate the role of cuticular waxes against environmental stresses; and 3- Develop the tools and methods required to study terpenes, another group of defence compounds of the black cottonwood tree. Even though the underlying question driving my research is why plants synthesize specialized metabolites, the knowledge generated has potential applications in crop improvement and industry. By understanding the biosynthesis and ecological role of specialized metabolites we will be able to breed or engineer plants better adapted to specific environments. Moreover, waxes and terpenes have commercial value as pharmaceuticals, pesticides, food additives, and biofuels. This program will require a multi-disciplinary approach that will train highly qualified personnel in genomics, biochemistry, analytical chemistry, plant physiology and biotechnology.