Padrón Peppers, Some Are Hot, and Some Are Not

Some peppers are pungent due to the presence of their secondary metabolite contents—capsaicinoids. The ability to synthesize capsaicinoids is a genetic trait, but the control of their accumulation in the fruit is more complex than just biosynthesis. Besides biosynthesis, other metabolic pathways, such as oxidation and conjugation, are also involved in capsaicinoid homeostasis. Moreover, all these pathways are modulated by different factors, namely plant hormones, transcription factors, ontogeny, and the environment, including both abiotic and biotic agents. In the present chapter, the present knowledge about the control of capsaicin metabolism in pepper is reviewed. Based on the literature and our own experience, there is a correlation between pungency and lignification. We have a clue about the reason: capsaicinoid and lignin metabolic pathways are related, and their biosynthesis predate from the same intermediate compounds. Finally, this chapter mainly focuses on the cultivar Padrón, a pungent variety used in our experiments because of its economic and cultural value.