J. Microbiol. Biotechnol. (2015), 25(5), 620–628 http://dx.doi.org/10.4014/jmb.1409.09071 Research Article Review jmb Identification and Characterization of an Antifungal Protein, AfAFPR9, Produced by Marine-Derived Aspergillus fumigatus R9 Qi Rao†, Wenbin Guo†, and Xinhua Chen* Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, P.R. China Received: September 23, 2014 Revised: October 29, 2014 A fungal strain, R9, was isolated from the South Atlantic sediment sample and identified as Accepted: November 13, 2014 Aspergillus fumigatus. An antifungal protein, AfAFPR9, was purified from the culture supernatant of Aspergillus fumigatus R9. AfAFPR9 was identified to be restrictocin, which is a member of the ribosome-inactivating proteins (RIPs), by MALDI-TOF-TOF-MS. AfAFPR9 First published online displayed antifungal activity against plant pathogenic Fusarium oxysporum, Alternaria longipes, November 14, 2014 Colletotrichum gloeosporioides, Paecilomyces variotii, and Trichoderma viride at minimum *Corresponding author inhibitory concentrations of 0.6, 0.6, 1.2, 1.2, and 2.4 µg/disc, respectively. Moreover, AfAFPR9 Phone: +86-592-2195297; exhibited a certain extent of thermostability, and metal ion and denaturant tolerance. The Fax: +86-592-2085376; iodoacetamide assay showed that the disulfide bridge in AfAFP was indispensable for its E-mail:
[email protected] R9 antifungal action. The cDNA encoding for AfAFPR9 was cloned from A. fumigatus R9 by RT- † These authors contributed PCR and heterologously expressed in E. coli. The recombinant AfAFP protein exhibited equally to this work. R9 obvious antifungal activity against C. gloeosporioides, T. viride, and A. longipes. These results reveal the antifungal properties of a RIP member (AfAFPR9) from marine-derived Aspergillus fumigatus and indicated its potential application in controlling plant pathogenic fungi.