**3. Being hot, but how much? Regulation of capsaicinoid levels**

The presence of capsaicin synthase (Pun1/AT3 or other protein) is enough to allow the biosynthesis of capsaicinoids in a pepper line because their precursors are synthesized from common plant pathways. However, there are other pathways involved in

capsaicin metabolism. Moreover, all those pathways are targets of fine-tune modulation in response to variations of different endogenous and exogenous factors. Hence, it is worthwhile to look at the present knowledge of regulation.
