Evolutionary divergence and regulatory landscapes of benzoxazinoid metabolism in monocot crops.

Throughout their evolutionary trajectory, plants have orchestrated a sophisticated repertoire of defense mechanisms to counteract pathogenic threats. Central to this chemical arsenal in monocotyledonous lineages is the benzoxazinoid (BX) metabolic pathway, a quintessential secondary metabolic route that dictates plant resilience. While the biosynthetic blueprint of BXs has been extensively mapped in models such as maize (Zea mays) and wheat (Triticum aestivum), the regulatory logic and evolutionary divergence within rice (Oryza sativa) remain largely enigmatic. This review provides a high-resolution synthesis of the BX landscape, critically contrasting the canonical maize model with the emerging, yet distinct, metabolic signatures observed in rice. We contend that a comparative analysis of BX diversity is fundamental to decrypting metabolic evolution and harnessing its potential for precision crop protection. Furthermore, we evaluate the multifunctional roles of BX compounds-positioning them not merely as direct biocidal toxins, but as pivotal signaling rheostats that modulate plant defense networks and multi-trophic ecological interactions. Collectively, this synthesis establishes a robust theoretical framework for the genetic fortification of crops.