title: Thanatin confers partial resistance against aflatoxigenic fungi in maize (Zea mays).
abstract: Aflatoxin-producing fungi can contaminate plants and plant-derived products with carcinogenic secondary metabolites that present a risk to human and animal health. In this study, we investigated the effect of antimicrobial peptides on the major aflatoxigenic fungi Aspergillus flavus and A. parasiticus. In vitro assays with different chemically-synthesized peptides demonstrated that the broad-spectrum peptide thanatin from the spined soldier bug (Podisus maculiventris) had the greatest potential to eliminate aflatoxigenic fungi. The minimal inhibitory concentrations of thanatin against A. flavus and A. parasiticus were 3.13 and 12.5 µM, respectively. A thanatin cDNA was subsequently cloned in a plant expression vector under the control of the ubiquitin-1 promoter allowing the recombinant peptide to be directed to the apoplast in transgenic maize plants. Successful integration of the thanatin expression cassette was confirmed by PCR and expression was demonstrated by semi-quantitative RT-PCR in transgenic maize kernels. Infection assays with maize kernels from T1 transgenic plants showed up to three-fold greater resistance against Aspergillus spp. infections compared to non-transgenic kernels. We demonstrated for the first time that heterologous expression of the antimicrobial peptide thanatin inhibits the growth of Aspergillus spp. in transgenic maize plants offering a solution to protect crops from aflatoxin-producing fungi and the resulting aflatoxin contamination in the field and under storage conditions.
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Houdelet
authors.affiliation: Institute of Phytopathology and Applied Zoology, Justus-Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kogel
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.|Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Fischer
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.|Institute of Phytopathology and Applied Zoology, Justus-Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schillberg
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany. greta.noelke@ime.fraunhofer.de.
authors.forename: Greta
authors.initials: G
authors.lastname: Nölke
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001230:Aspergillus / Q000145:classification / Q000472:pathogenicity*; D013045:Species Specificity; D003313:Zea mays / Q000382:microbiology*
chemical_list: D023181:Antimicrobial Cationic Peptides; C098076:thanatin
keywords: Aflatoxin; Aspergillus flavus; Aspergillus parasiticus; Corn; Transgenic plants