Alpha-dioxygenase that catalyzes the primary oxygenation step of a variety of 14-20 carbon fatty acids, containing up to three unsaturated bonds, into their corresponding 2R-hydroperoxides (PubMed:12060227, PubMed:10455113). Involved in the production of oxylipins that function in cell signaling, wound healing, and protection from infection (PubMed:12060227, PubMed:10455113). Mediates protection against oxidative stress and cell death, probably by generating some lipid-derived molecules (PubMed:12060227). Promotes local and systemic plant defense in a salicylic acid (SA)-dependent manner, including the establishment of systemic acquired resistance (SAR) in response to incompatible interaction (PubMed:22199234). Involved in a negative regulation of abscisic acid (ABA)-mediated signaling pathway (PubMed:22199234). a 1,2-saturated fatty acid + O2 = a (2R)-2-hydroperoxy fatty acid (9Z,12Z,15Z)-octadecatrienoate + O2 = (R)-2-hydroperoxy-(9Z,12Z,15Z)-octadecatrienoate hexadecanoate + O2 = (2R)-2-hydroperoxyhexadecanoate (9Z,12Z)-octadecadienoate + O2 = (2R,9Z,12Z)-2-hydroperoxyoctadecadienoate (9Z)-octadecenoate + O2 = (2R,9Z)-2-hydroperoxyoctadecenoate Binds 1 heme b (iron(II)-protoporphyrin IX) group per subunit. Binds 1 calcium ion per subunit. Forms monomers in solution. Localizes on the surface of leaf oil bodies. Expressed in roots (epiderm), mature flowers (e.g. anthers) and senescing leaves. Induced by salicylic acid (SA) and by some chemicals generating reactive oxygen species (ROS, e.g. nitric oxide (NO), intracellular superoxide and singlet oxygen) such as sodium nitropruside (SNP), paraquat and rose bengal (RB). Accumulates locally, at the infection site, in response to both incompatible and compatible bacterial pathogens (e.g. Pseudomonas syringae pv. tomato DC3000) in a SA-dependent manner, with a faster response during hypersensitive reactions. Slightly higher accumulation of Pseudomonas syringae pv. tomato DC3000 in infected leaves. Partially impaired systemic acquired resistance (SAR) in response to incompatible interaction. When associated with LOX1 disruption; hypersensitivity to the growth-inhibitory effect of abscisic acid (ABA) accompanied by an accumulation of ABA-inducible marker genes. Belongs to the peroxidase family.