title: Antimicrobial properties of two novel peptides derived from Theobroma cacao osmotin.
abstract: The osmotin proteins of several plants display antifungal activity, which can play an important role in plant defense against diseases. Thus, this protein can be useful as a source for biotechnological strategies aiming to combat fungal diseases. In this work, we analyzed the antifungal activity of a cacao osmotin-like protein (TcOsm1) and of two osmotin-derived synthetic peptides with antimicrobial features, differing by five amino acids residues at the N-terminus. Antimicrobial tests showed that TcOsm1 expressed in Escherichia coli inhibits the growth of Moniliophthora perniciosa mycelium and Pichia pastoris X-33 in vitro. The TcOsm1-derived peptides, named Osm-pepA (H-RRLDRGGVWNLNVNPGTTGARVWARTK-NH2), located at R23-K49, and Osm-pepB (H-GGVWNLNVNPGTTGARVWARTK-NH2), located at G28-K49, inhibited growth of yeasts (Saccharomyces cerevisiae S288C and Pichia pastoris X-33) and spore germination of the phytopathogenic fungi Fusarium f. sp. glycines and Colletotrichum gossypi. Osm-pepA was more efficient than Osm-pepB for S. cerevisiae (MIC=40μM and MIC=127μM, respectively), as well as for P. pastoris (MIC=20μM and MIC=127μM, respectively). Furthermore, the peptides presented a biphasic performance, promoting S. cerevisiae growth in doses around 5μM and inhibiting it at higher doses. The structural model for these peptides showed that the five amino acids residues, RRLDR at Osm-pepA N-terminus, significantly affect the tertiary structure, indicating that this structure is important for the peptide antimicrobial potency. This is the first report of development of antimicrobial peptides from T. cacao. Taken together, the results indicate that the cacao osmotin and its derived peptides, herein studied, are good candidates for developing biotechnological tools aiming to control phytopathogenic fungi.
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Loeni L
authors.initials: LL
authors.lastname: Falcao
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Joseilde O
authors.initials: JO
authors.lastname: Silva-Werneck
authors.affiliation: Federal University of the South and Southeast of Pará (Unifesspa), Pará, Brazil.
authors.forename: Alessandra de R
authors.initials: Ade R
authors.lastname: Ramos
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Natalia F
authors.initials: NF
authors.lastname: Martins
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bresso
authors.affiliation: Centro Universitário Planalto do Distrito Federal (Uniplan), Brasília, DF, Brazil.
authors.forename: Magali A
authors.initials: MA
authors.lastname: Rodrigues
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil.
authors.forename: Marcelo P
authors.initials: MP
authors.lastname: Bemquerer
authors.affiliation: Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil. Electronic address: lucilia.marcellino@embrapa.br.
authors.forename: Lucilia H
authors.initials: LH
authors.lastname: Marcellino
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001487:Basidiomycota / Q000187:drug effects; D002099:Cacao / Q000737:chemistry*; D020231:Colletotrichum / Q000187:drug effects; D005670:Fusarium / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D025282:Mycelium / Q000187:drug effects; D010843:Pichia / Q000187:drug effects; D010940:Plant Proteins / Q000737:chemistry / Q000494:pharmacology*; D000072417:Protein Domains; D012441:Saccharomyces cerevisiae / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D010940:Plant Proteins
keywords: Antifungal activity; Antimicrobial peptide; Cacao; Moniliophthora perniciosa; Osmotin-like protein; Pathogenesis-related; Phytopathogens; Yeast