Maybe involved in defense responses to X.campestris, but probably not a X.campestris pv. campestris race 750 (e.g. Xcc750) resistance gene; according to genetic data, linked to a locus influencing resistance to Xcc750. Expressed in leaves, flowers and stems, but not in roots. Accumulates upon infection by the phytopathogenic bacterium X.campestris pv. campestris (both compatible and incompatible strains Xcc168 and Xcc750, respectively), agent of black rot (PubMed:8018872). Accumulates at higher levels in light than in darkness. Repressed by MIF1 (PubMed:16412086). Absent in the susceptible ecotype cv. Oy-0 (PubMed:8018872). Only present in ecotypes resistant against X.campestris pv. campestris race 750 (e.g. Xcc750) (PubMed:9869403).