Elicitins: proteins in search of a role?

The literature on elicitins, proteins secreted by many species of P hytophthora and some species of the related genus Pythium in culture, is reviewed. The review covers both the properties of elicitins as proteins and their role in the biology of the secreting organism. It is proposed that in plant species other than tobacco, elicitins play no role in the determination of pathogenicity. In the specific case of tobacco they appear to have taken on this role, possibly as a result of mutation in a tobacco cell membrane protein associated with some aspect of transmembrane signalling. It is suggested that the altered affinity of elicitins for this mutant plant protein resulted in a change in the regulation of the signal transduction pathway, inducing a hypersensitive-like response in the presence of elicitins, resulting in a new role for these proteins as avirulence factors. Australasian Plant Pathology 25(3) 148 - 157 Full text doi:10.1071/AP96028 © CSIRO 1996