Within the process of evolution plants were in contact with wide range of potential pathogens, including viruses, bacteria, fungi, oomycetes, nematodes or insects. So, consequently plants have developed various strategies to defence themselves from potential attack. Plant pathogen attacks are perceived through pathogen-issued compounds or plant-derived molecules that elicit defence reactions. We have applied as a model interaction of basic elicitin cryptogein, produced by Phytophthora cryptogea, with plants Nicotiana tabacum. Cryptogein is a small 10kDa holoprotein inducing on tobacco plants cascade of defence responses including protein phosphorylations, changes in ion fluxes across the plasma membrane, production of active oxygen species, nitric oxide, phytoalexins, and reinforcement of cell wall or expression of pathogenesis related proteins. Usually all these signalling events could contribute to development of systemic acquired resistance to a wide spectrum of pathogen in non-infected parts of plant. However, the precise biological role of elicitins is still not known their ability to bind sterols and fatty acids, has been described. The cryptogein-sterol complex was suggested to be necessary for triggering of early events such as active oxygen species production or pH changes. On the other hand the ability to stimulate necrosis and expression of defence proteins seems to be not dependent on sterol binding. To verify this theory a series of cryptogein mutants M35W/M59W, L19R and L15W/L36F with altered abilities to bind sterols and fatty acids were prepared. A clear relationship between the caspidiol production, sterol binding and AOS production was demonstrated. However, in the case of expression of genes for pathogenesis related (PR) proteins of classes 1, 3 and 5 different patterns were observed in relation to sterol binding properties. Moreover, only in PR1a protein a clear relation between the SA accumulation and gene expression was found.