Biosynthesis of plant extracellular lipids

未来几十年，全球农业将面临许多挑战，包括全球气候模式预测变化带来的挑战。在这种情况下，详细了解植物的适应性，保护它们免受环境胁迫，如干旱、盐胁迫和病原体的攻击，对于培育更具抗逆性的作物品种至关重要。我的NSERC发现研究项目旨在了解植物中由聚合脂质和相关蜡组成的保护性表面屏障的生物合成。这些与化学相关的屏障是：1)覆盖在植物空气表面的角质层，2)存在于包括根在内的各种外部和内部组织层的细胞壁中的亚木质素，以及3)存在于花粉孢子外壳最外层的孢粉列宁。需要大量酶的协同活动来产生形成这些表面脂质基质的各种脂肪酸衍生物。在接下来的五年里，我的研究团队将对产生以下表面脂质分子的三类酶进行表征：1)脂肪醇，2)游离脂肪酸，和3)烷烃（完全还原的碳氢化合物分子，类似于汽油）。我们还将描述编码这些酶的基因突变和过表达对植物抵御环境胁迫能力的影响。这将进一步深入了解植物表面脂质屏障的结构和功能。植物表面脂质除了为耐应力植物的发展提供信息和工具外，还由可再生碳氢化合物组成，在化学上适合替代石油产品作为能源和化学原料的来源。在分子水平上了解植物表面脂质生物合成的基本知识对于充分利用这一可再生化学资源至关重要。总之，该研究将提供一系列植物脂质修饰酶的重要基础知识，并深入了解基于脂质表面屏障的生态生理功能。此外，该计划还将为学生提供植物分子生物技术方面的高级培训。

Agriculture worldwide will face many challenges over the coming decades, including those imposed by predicted changes in global climate patterns. In this context, a detailed understanding of plant adaptations that protect them against environmental stresses, such as drought, salt stress and pathogen attack, is critical for generating crop varieties that are more stress resistant. My NSERC Discovery research program is aimed at understanding the biosynthesis in plants of protective surface barriers that are composed of polymerized lipids and associated waxes. These chemically-related barriers are: 1) cuticle coating the aerial surfaces of plants, 2) suberin found in the cells walls of various external and internal tissue layers including roots, and 3) sporopollenin found in the outermost layer of the pollen spore coat. The coordinated activities of a large number of enzymes are required to produce the variety of fatty acid derivatives that form these surface lipid matrices. Over the next five years, my research team will characterize three classes of enzymes producing the following surface lipid molecules: 1) fatty alcohols, 2) free fatty acids, and 3) alkanes (fully reduced hydrocarbon molecules, similar to gasoline). We will also characterize the effects of mutating and over-expressing the genes encoding these enzymes on the ability of plants to withstand environmental stressors. This will give further insights into the structures and functions of plant surface lipid barriers. In addition to providing information and tools for the development of stress-tolerant plants, plant surface lipids are composed of renewable hydrocarbons that are chemically suitable for replacement of petroleum products as sources of energy and chemical feedstocks. Fundamental knowledge of plant surface lipid biosynthesis at the molecular level is critical for harnessing this renewable chemical resource to its full potential. Altogether, the proposed research will provide important fundamental knowledge of a set of plant lipid modification enzymes and insights into the ecophysiological functions of lipid-based surface barriers. In addition, the program will provide advanced training to students in plant molecular biotechnology.