Capsaicinoids: Pungency beyond Capsicum

Capsaicinoids are metabolites responsible for the appealing pungency of Capsicum (chili pepper) species. The completion of the Capsicum annuum genome has sparked new interest into the development of biotechnological applications involving the manipulation of pungency levels. Pungent dishes are already part of the traditional cuisine in many countries, and numerous health benefits and industrial applications are associated to capsaicinoids. This raises the question of how to successfully produce more capsaicinoids, whose biosynthesis is strongly influenced by genotype–environment interactions in fruits of Capsicum. In this Opinion article we propose that activating the capsaicinoid biosynthetic pathway in a more amenable species such as tomato could be the next step in the fascinating story of pungent crops. Capsaicinoids are secondary metabolites that confer Capsicum (‘chili’ peppers) fruits their appealing pungency (‘heat’) and have multiple proven health benefits and industrial applications. Five Capsicum species have been domesticated. However, even in fruits of the same species, pungency is not consistent owing to the strong influence of the environment on capsaicinoid levels. Furthermore, multiple agronomic issues are prevalent in chili pepper cultivation, such as wilting in hot days, flower drop, and virus susceptibility. Capsicum belongs to the Solanaceae family, and recent completion of its full genome sequence shows that inactive genes for the biosynthetic pathway of capsaicinoids are also present in tomato. We propose that the use of state-of-the-art genome engineering techniques to activate capsaicinoid biosynthesis in tomato is a suitable option to exploit these valuable secondary compounds.