Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich.
mehr Informationen...
The Fusarium graminearum cerato-platanins loosen cellulose substrates enhancing fungal cellulase activity as expansin-like proteins
Ist Teil von
Plant physiology and biochemistry, 2019-06, Vol.139, p.229-238
Ort / Verlag
France: Elsevier Masson SAS
Erscheinungsjahr
2019
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
Cerato-platanin proteins (CPPs) are small non-catalytic, cysteine-rich hydrophobic proteins produced by filamentous fungi. The genome of Fusarium graminearum, the causal agent of Fusarium head blight disease of wheat and other cereal grains, contains two genes putatively encoding for CPPs. To better characterize their features, the two FgCPPs were heterologously expressed in Pichia pastoris. The recombinant FgCPPs reduced the viscosity of a cellulose soluble derivate (carboxymethyl cellulose, CMC). The same effect was not observed on other polysaccharide substrates such as chitin, 1,3-β-glucan, xylan and pectin. Indeed, differently from other fungal CPPs and similarly to expansins, FgCPPs are trapped by cellulose and not by chitin, thus suggesting that these proteins interact with cellulose. A double knock-out mutant deleted of both FgCPPs encoding genes produces much more cellulase activity than the corresponding wild type strain when grown on CMC, likely compensating the absence of FgCPPs. This result prompted us to investigate a possible synergistic effect of these proteins with fungal cellulases. The incubation of FgCPPs in the presence of a fungal cellulase (EC 3.2.1.4) determines an increased enzymatic activity on CMC, filter paper and wheat cell walls. The observation that FgCPPs act with a non-hydrolytic mechanism indicates that these proteins favor fungal cellulase activity in an expansin-like manner. Though the disruption of the FgCPP genes had no demonstrable impact on fungal virulence, our experimental data suggest their probable involvement in virulence, thus we refer to them as accessory virulence genes. Our results suggest also that the FgCPPs could be exploited for future biotechnological application in second-generation biofuels production on lignocellulosic biomasses rich in cellulose. Finally, we demonstrate that FgCPPs act as elicitors of defense responses on Arabidopsis leaves, increasing resistance to Botrytis cinerea infections.
•Two F. graminearum cerato-platanin proteins have been heterologously expressed.•FgCPPs act by a non-hydrolytic mechanism reducing carboxymethyl cellulose (CMC) viscosity.•Carbohydrate binding assay shows that FgCPPs are trapped by CMC and not by chitin.•As expansin proteins, FgCPPs enhance enzymatic hydrolysis of cellulosic substrates.•FgCPPs elicit defense responses increasing Arabidopsis resistance to B. cinerea.