Plants have evolved complex signaling pathways to coordinate responses to developmental and environmental information. The oxylipin pathway is one pivotal lipid-based signaling network, composed of several competing branch pathways, that determines the plant’s ability to adapt to various stimuli. Activation of the oxylipin pathway induces the de novo synthesis of biologically active metabolites called “oxylipins”. The relative levels of these metabolites are a distinct indicator of each plant species and determine the ability of plants to adapt to different stimuli. The two major branches of the oxylipin pathway, allene oxide synthase (AOS) and hydroperoxide lyase (HPL) are responsible for production of the signaling compounds, jasmonates and aldehydes respectively. Here, we compare and contrast the regulation of AOS and HPL branch pathways in rice and Arabidopsis as model monocotyledonous and dicotyledonous systems. These analyses provide new insights into the evolution of JAs and aldehydes signaling pathways, and the complex network of processes responsible for stress adaptations in monocots and dicots.Author for correspondence. Tel: +1 (530) 752 8187; Fax: +1 (530) 752 5410; E-mail: kdehesh@ucdavis.edu