Grass inflorescence architecture and evolution: the origin of novel signaling centers

A central goal of evo-devo is to understand how morphological diversity arises from existing developmental mechanisms, requiring a clear, predictive explanatory framework of the underlying developmental mechanisms. Despite an ever-increasing literature on genes regulating grass inflorescence development, an effective model of inflorescence patterning is lacking. I argue that the existing framework for grass inflorescence development, which invokes homeotic shifts in multiple distinct meristem identities, obscures a recurring theme emerging from developmental genetic studies in grass models, that is that inflorescence branching is regulated by novel localized signaling centers. Understanding the origin and function of these novel signaling centers will be key to future evo-devo work on the grass inflorescence.