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Title: Novel mode of action of plant defense peptides: hevein-like antimicrobial peptides from wheat inhibit fungal metalloproteases

item SLAVOKHOTOVA, ANNA - Russian Academy Of Sciences
item Naumann, Todd
item Price, Neil
item ROGOZHIN, EUGENE - Russian Academy Of Sciences
item ANDREEV, YAROSLAV - Russian Academy Of Sciences
item VASSILEVSKI, ALEXANDER - Russian Academy Of Sciences
item ODINTSOVA, TATYANA - Russian Academy Of Sciences

Submitted to: FEBS Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2014
Publication Date: 5/1/2014
Citation: Slavokhotova, A.A., Naumann, T.A., Price, N.P., Rogozhin, E.A., Andreev, Y.A., Vassilevski, A.A., Odintsova, T.I. 2014. Novel mode of action of plant defense peptides: hevein-like antimicrobial peptides from wheat inhibit fungal metalloproteases. FEBS Journal. 281(20):4754-4764.

Interpretive Summary: Plant chitinases, like the corn ChitA protein, are proteins that help plants resist fungal diseases. Our previous research identified a fungal protein called Fv-cmp that promotes disease by degrading ChitA during corn ear rot. In this research, we discovered a wheat antimicrobial peptide (WAMP), that protects ChitA by inhibiting Fv-cmp activity. In laboratory experiments, adding WAMP to solutions containing both ChitA and Fv-cmp stopped ChitA degradation. This information is important because it suggests that genetically engineered corn and other plants expressing WAMPs could have improved fungal disease resistance and less mycotoxin contamination. This discovery, moreover, will aid scientists that study plant antimicrobial compounds.

Technical Abstract: The multilayered plant immune system relies on rapid recognition of pathogen-associated molecular patterns followed by activation of defense-related genes that results in the reinforcement of plant cell walls and production of antimicrobial compounds. To suppress plant defense, fungi secrete effectors including a recently discovered Zn-metalloproteinase from Fusarium verticillioides, named fungalysin Fv-cmp (Naumann et al. 2011). This proteinase cleaves class IV chitinases, plant defense proteins that bind and degrade chitin of fungal cell walls. In this work, we studied plant response to such pathogen invasion and discovered novel potent inhibitors of fungalysin. We produced several recombinant hevein-like antimicrobial peptides named WAMPs containing different amino acids (A, K, E, and N) at the non- conservative position 34. An additional serine residue in the site of fungalysin proteolysis makes the peptides resistant to the protease. Moreover, WAMPs were able to inhibit fungalysin thus protecting chitinases from cleavage and keeping them active against fungi. WAMPs represent a novel type of protease inhibitors being active against fungal metalloproteases. According to in vitro antifungal assays WAMPs demonstrated direct inhibition of hypha elongation suggesting fungalysin-independent inhibition strategy. Therefore WAMPs were shown to be multifunctional peptides playing a key role in plant defense response. A novel molecular mechanism of dynamic interplay between host defense molecules and fungal virulence factors is suggested.