Thanatin confers partial resistance against aflatoxigenic fungi in maize (Zea mays)

• Published in: Transgenic research Vol. 24; no. 5; pp. 885 - 895
• Main Authors: Schubert, Max, Houdelet, Marcel, Kogel, Karl-Heinz, Fischer, Rainer, Schillberg, Stefan, Nölke, Greta
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.10.2015; Springer Nature B.V
• Subjects: Animal Genetics and Genomics; Antimicrobial Cationic Peptides - pharmacology; Aspergillus - classification; Aspergillus - pathogenicity; Aspergillus flavus; Aspergillus parasiticus; Biomedical and Life Sciences; Biomedical Engineering/Biotechnology; Genetic Engineering; Life Sciences; Molecular Medicine; Original Paper; Plant Genetics and Genomics; Podisus maculiventris; Species Specificity; Transgenics; Zea mays; Zea mays - microbiology; Corn; Transgenic plants; Aflatoxin; Aspergillus parasiticus; Aspergillus flavus
• ISSN: 0962-8819; 1573-9368
• DOI: 10.1007/s11248-015-9888-2

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.