Genomic Basis of Specificity in Glucosinolate Hydrolysis

植物产生大量的次生代谢物，部分是由共同的主干结构的不同结构修饰产生的。硫代葡萄糖苷是一种低分子质量、富硫的硫代葡萄糖苷，是单个分子主干如何被修饰以产生一系列令人惊叹的次生代谢物的最好例子。一个单一的物种，拟南芥，可以从蛋氨酸硫代葡萄糖苷骨架中产生30种不同的硫代葡萄糖苷，这些硫代葡萄糖苷在硫代葡萄糖苷水解过程中可以扩增成100多种不同的化合物。硫代葡萄糖苷的生物活性是在蛋白质黑芥子酶降解后完全实现的。这会产生一系列不同的化合物，如异硫氰酸酯、腈和表硫腈，这些化合物对人类健康有不同的影响。拟南芥是许多十字花科蔬菜的近亲，许多遗传位点决定了硫代葡萄糖苷的水解途径。之前仅在遗传方面定义的一个基因座ESM1将被克隆并在分子水平上进行表征。此外，还将研究ESM1对硫代葡萄糖苷水解的生化影响。硫代葡萄糖苷结构修饰有助于控制各种生物活性，帮助植物抵御昆虫、线虫和真菌的侵害，并包含在普通十字花科作物中进行修饰时极大地有利于人类营养的潜力。控制硫代葡萄糖苷生物活性的一个关键步骤是水解步骤。这一步骤控制了生物活性显著不同的化合物的生产。例如，给定的硫代葡萄糖苷的异硫氰酸酯比相应的腈具有更强的防癌活性和抗昆虫/真菌活性。拟南芥硫代葡萄糖苷水解酶系统的特征可能会影响到从生态学到进化到人类营养的各个领域。此外，ESM1基因座可能有助于培育抗虫性和抗病原性改变的作物，以及改变人类食用的营养价值。此外，让本科生和博士后研究人员参与这个项目将使他们接触到广泛的技术，并有助于为他们自己未来的研究培训他们。

Plants produce a vast catalog of secondary metabolites, partly generated by diverse structural modifications of common backbone structures. Glucosinolates, low-molecular-weight, sulfur rich thioglucosides, are a prime example of how a single molecular backbone can be modified to produce an amazing array of secondary metabolites. A single species, Arabidopsis thaliana, can derive 30 different glucosinolates from the methionine glucosinolate backbone that can be amplified to over 100 different compounds during glucosinolate hydrolysis. The biological activity of a glucosinolate is fully realized after degradation by the protein, myrosinase. This produces a series of different compounds such as isothiocyanates, nitriles, and epithionitriles that differentially impact human health. In Arabidopsis, a relative of many brassica vegetables, numerous genetic loci determine the hydrolytic path of glucosinolates. One locus, ESM1, previously defined only in genetic terms, will be cloned and characterized at the molecular level. Further, the biochemical impact of ESM1 on glucosinolate hydrolysis will be investigated. Glucosinolate structural modifications serve to control diverse biological activities that help the plant defend itself from insects, nematodes, fungi as well as containing the potential to greatly benefit human nutrition when modified in common Brassica crops. A key point in controlling glucosinolate biological activity is at the hydrolysis step. This step controls the production of compounds with dramatic differences in biological activity. For example, a given glucosinolate's isothiocyanate exhibits stronger cancer prevention activities and anti-insect/fungal activities than do the corresponding nitriles. Characterizing the Arabidopsis glucosinolate hydrolytic system could impact fields ranging from ecology to evolution to human nutrition. Additionally, the ESM1 locus may be useful in producing crops with altered insect and pathogen resistance as well as altered nutritional value for human consumption. Further, involving undergraduates and postdoctoral researchers in this project will expose them to a broad range of techniques and help to train them for their own future research.