The domain corresponds to the mature part of the Ecp2 effector protein from the tomato pathogen Cladopsorium fulvum. Effectors are low molecular weight proteins that are secreted by bacteria, oomycetes and fungi to manipulate their hosts and adapt to their environment. Ecp2 is a 165 amino acid secreted protein that was originally identified as a virulence factor in C. fulvum, since disruption reduces virulence of the fungus on tomato plants. We have recently determined that Ecp2 is a member of a novel, widely distributed and highly diversified within the fungal kingdom multigene superfamily, which we have designated Hce2, for Homologs of C. fulvum Ecp2 effector. Although Ecp2 is present in most organisms as a small secreted protein, the mature part of this protein can be found fused to other protein domains, including the fungal Glycoside Hydrolase family 18, Glyco_hydro_18 pfam00704 and other, unknown, protein domains. The intrinsic function of Ecp2 remains unknown but it is postulated by that it is a necrosis-inducing factor in plants that serves pathogenicity on the host.