Intergrated biochemical genomics and cellular platform for alkaloid biosynthetic gene discovery and characterization

植物无与伦比的生物合成能力长期以来一直被利用，通过许多物种在传统医学中的使用和纯代谢物作为药物、香精、香料、色素、杀虫剂和其他精细化学品的应用。苯基异喹啉生物碱（BIAs）是一类由酪氨酸衍生而来的植物特化代谢物，通过分子内偶联、还原、甲基化、羟基化等反应形成的复杂生化网络而多样化，可产生约2500种已知结构。几种倚倚性药物（如镇痛药吗啡、止咳药可待因、血管扩张剂罂粟碱和管curarine）直接用作药物，或用作半合成药物（如羟考酮）的前体。由于这些化合物的化学复杂性，植物仍然是唯一经济的来源，这使得重新合成具有挑战性和成本高昂。大多数关于BIA代谢的研究针对的是生物合成酶和相应的基因，这些基因只在有限的物种中参与了相对较少的化合物的形成。植物特化代谢的一个重要特征是酶通过随机突变获得新功能的能力。因此，相对有限的几种酶类型（即sam依赖的甲基转移酶、乙酰辅酶a依赖的酰基转移酶、p450依赖的单加氧酶、fad依赖的氧化还原酶、短链脱氢酶/还原酶和醛酮还原酶）在很大程度上负责建立不同的主链结构和功能基取代，从而导致BIA结构的多样性。基于整合和比较来自培养植物物种的代谢物和转录谱的功能基因组学策略将用于鉴定和表征新的BIA生物合成酶。基因组学资源和分子遗传学工具将用于鉴定和调节参与BIA代谢调节的转录因子。将确定新发现的BIA生物合成酶的细胞和亚细胞定位，并研究可能的酶相互作用。

The unparalleled biosynthetic capacity of plants has long been exploited through the use of many species in traditional medicine and the application of pure metabolites as pharmaceuticals, flavours, fragrances, pigments, insecticides, and other fine chemicals. Benzylisoquinoline alkaloids (BIAs) are a large group of plant specialized metabolites derived from tyrosine and diversified by an intricate biochemical network of intramolecular coupling, reduction, methylation, hydroxylation, and other reactions that generate >2,500 known structures. Several BIAs (e.g. the analgesic morphine, the cough suppressant codeine, and the vasodilators papaverine and tubocurarine) serve directly as pharmaceuticals, or as precursors for semi-synthetic drugs (e.g. oxycodone). Plants remain the only economical source for these compounds due to their chemical complexity, which makes de novo synthesis challenging and costly. Most research on BIA metabolism has targeted biosynthetic enzymes and corresponding genes involved in the formation of relatively few compounds in only a limited number of species. An important feature of plant specialized metabolism is the ability of enzymes to acquire novel functions through random mutation. As such, a relatively limited number of enzyme types (i.e. SAM-dependent methyltransferases, acetylCoA-dependent acyltransferases, P450-dependent monooxygenases, FAD-dependent oxidoreductases, short-chain dehydrogenase/reductases and aldo-keto reductases) are largely responsible for the establishment of the diverse backbone structures and functional group substitutions responsible for BIA structural diversity. A functional genomics strategy based on the integration and comparison of metabolite and transcript profiles from a collection of cultured plant species will be used to identify and characterize novel BIA biosynthetic enzymes. Genomics resources and molecular genetic tools will be used to identify and modulate transcription factors involved in the regulation of BIA metabolism. The cellular and subcellular localization of newly discovered BIA biosynthetic enzymes will be determined, and possible enzyme interactions will also be investigated.