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通过在传统医学中使用许多物种以及将纯代谢物应用于药物，香料，香料，颜料，杀虫剂和其他精细化学品而得到开发。苄基异喹啉生物碱（BIA）是一大类植物特化代谢产物，由酪氨酸衍生，通过分子内偶联、还原、甲基化、羟基化等复杂的生化网络而多样化，产生超过2,500种已知结构。几种BIA（例如镇痛剂吗啡、止咳剂可待因以及血管扩张剂罂粟碱和筒箭毒碱）直接用作药物，或作为半合成药物（例如羟考酮）的前体。由于其化学复杂性，植物仍然是这些化合物的唯一经济来源，这使得从头合成具有挑战性且成本高昂。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，这些酶和基因仅在有限数量的物种中参与形成相对较少的化合物。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，相对有限数量的酶类型（即SAM依赖性甲基转移酶、乙酰辅酶A依赖性酰基转移酶、P450依赖性单加氧酶、FAD依赖性氧化还原酶、短链脱氢酶/还原酶和醛酮还原酶）主要负责建立不同的主链结构和负责BIA结构多样性的官能团取代。一个功能基因组学策略的基础上的整合和比较的代谢产物和转录谱从一个集合的培养植物物种将被用来识别和表征新的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。新发现的BIA生物合成酶的细胞和亚细胞定位将被确定，并且可能的酶相互作用也将被研究。

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.