Why are Chiles Hot? An Integrative Exploration of Secondary Metabolite Function in Ripe Fruit

非技术性总结“为什么辣椒是热的？成熟水果中次级代谢物功能的综合探索“Doug Levey和约书亚Tewksbury佛罗里达大学众所周知，智利水果中的辛辣化合物辣椒素对人体有许多生理作用。 虽然辣椒素被广泛用于医学，是世界上最重要的香料之一，但辣椒素的进化基础仍然是个谜。 这种化合物为什么以及如何进化的？ 它的功能是次要的（非适应性的），还是它在辣椒中的存在可以解释为食果动物的选择性压力？ 由于类似的次级化合物在其他水果中很常见，我们的工作将同时解决一个长期存在的悖论：为什么许多植物在成熟的水果中放置对食果动物明显有毒的化合物？六个假设的作用，在成熟的水果，使用辣椒和辣椒素作为模型系统的次生代谢产物将进行测试。 这项工作将包括对圈养食果动物进行实验室试验，以及对两种在地理和遗传上相距甚远的智利物种进行实地研究。 一个发生在亚利桑那州，另一个发生在玻利维亚。 在玻利维亚，有一种非刺激性的品种（即，它缺乏辣椒素）。 通过比较从微生物到脊椎动物的各种食果动物对辛辣和非辛辣辣椒的消费，我们将能够确定辣椒素对食果动物行为的影响。 平行研究将使用含有和不含辣椒素的人造水果。 这些实验将使我们更好地理解辣椒素的进化功能，并为辣椒素在人类健康、害虫管理、食品储存和智利种植方面的潜在应用铺平道路。

Non-technical summary of "Why are chiles hot? An integrative exploration of secondary metabolite function in ripe fruit"Doug Levey and Joshua TewksburyUniversity of FloridaIt is well known that the pungent compound in chile fruits, capsaicin, has many physiological effects in humans. Although it is widely used in medicine and is one of the most important spices in the world, the evolutionary basis for capsaicin remains mysterious. Why and how did the compound evolve? Is its function secondary (non-adaptive) or can its presence in chiles be explained by selective pressures of frugivores? Because similar secondary compounds are common in other fruits, our work will simultaneously address a long-standing paradox: Why do many plants place compounds in ripe fruit that are apparently toxic to fruit-eating animals? Six hypotheses for the role of secondary metabolites in ripe fruit, using chiles and capsaicin as a model system will be tested. The work will entail laboratory trials with captive frugivores and field studies on two chile species that are widely separated geographically and phylogenetically. One occurs in Arizona, the other in Boliva. In Boliva, a variety is available that is non-pungent (i.e., it lacks capsaicin). By comparing consumption of pungent and non-pungent chiles by a wide diversity of frugivores, from microbes to vertebrates, we will be able to determine the effect of capsaicin on frugivore behavior. Parallel studies will use artificial fruits made with and without capsaicin. These experiments will lead to a better understanding of capsaicin's evolutionary function and will pave the way for potential applications of capsaicin in human health, pest management, food storage, and chile cultivation.