Cerato-platanins: a fungal protein family with intriguing properties and application potential

Abstract

Cerato-platanin proteins are small, secreted proteins with four conserved cysteines that are abundantly produced by filamentous fungi with all types of lifestyles. These proteins appear to be readily recognized by other organisms and are therefore important factors in interactions of fungi with other organisms, e.g. by stimulating the induction of defence responses in plants. However, it is not known yet whether the main function of cerato-platanin proteins is associated with these fungal interactions or rather a role in fungal growth and development. Cerato-platanin proteins seem to unify several biochemical properties that are not found in this combination in other proteins. On one hand, cerato-platanins are carbohydrate-binding proteins and are able to bind to chitin and N-acetylglucosamine oligosaccharides; on the other hand, they are able to self-assemble at hydrophobic/hydrophilic interfaces and form protein layers, e.g. on the surface of aqueous solutions, thereby altering the polarity of solutions and surfaces. The latter property is reminiscent of hydrophobins, which are also small, secreted fungal proteins, but interestingly, the surface-activity-altering properties of cerato-platanins are the opposite of what can be observed for hydrophobins. The so far known biochemical properties of cerato-platanin proteins are summarized in this review, and potential biotechnological applications as well as implications of these properties for the biological functions of cerato-platanin proteins are discussed.

Comparative and transcriptional analysis of the predicted secretome in the lignocellulose‐degrading basidiomycete fungus Pleurotus ostreatus

“…The biochemical functions of cerato‐platanins remain elusive. De Oliveira and colleagues () showed that they had a structure similar to expansins and barwin‐like endoglucanases, suggesting an activity involved in carbohydrate metabolism (Baccelli et al ., ; Gaderer et al ., ). However, they have no activity against a variety of carbohydrates.…”

Comparative genomics reveals unique wood‐decay strategies and fruiting body development in the Schizophyllaceae

“…These properties and their developmental expression in axenic fruiting bodies suggest a role in FCW remodeling, although antimicrobial activities also have been predicted for certain members (Krizsán et al ., ). Cerato‐platanins represent a similar case (see also above); they are widely expressed in pathogenic fungi–plant interactions (Chen et al ., ; Gaderer et al ., ), fruiting bodies (Gaderer et al ., ; Sipos et al ., ; Krizsán et al ., ) and assays of fungal defense against predators (Plaza et al ., ), and are significantly enriched in Agaricomycetes genomes (Chen et al ., ; Krizsán et al ., ). Thaumatins and cerato‐platanins provide examples of gene families traditionally associated with plant pathogenicity but for which deeper analyses reveal morphogenetic functions, suggesting a link between morphogenesis and pathogenicity.…”

Overexpression of MoSM1, encoding for an immunity-inducing protein from Magnaporthe oryzae, in rice confers broad-spectrum resistance against fungal and bacterial diseases

“…Many members that belong to the cerato-platanin family have been characterized from filamentous fungi including M. oryzae and B. cinerea and some of them have shown to trigger immunity in a number of plant species2223. We and others have shown that, transient or stable expression of MoSM1 in Arabidopsis or application of recombinant MoMSP1 in rice activated a series of defense responses, which conferred a broad-spectrum resistance against fungal and bacterial pathogens3242.…”

“…The cerato-platanin (CP) family is a newly identified small, secreted and cysteine-rich protein (~150 aa) family from filamentous fungi222324. CP was first identified from the tree pathogen Ceratocystis platani (formerly known as Ceratocystis fimbriata f. sp.…”

“…Further study revealed that the elicitor activity of the B. cinerea BcSpl1 resides in a two-peptide motif on the protein surface29. It was thus suggested that members of the CP family represent a novel class of proteins with potential PAMP activity as plant defense elicitors used in disease control222324.…”