Transgenic expression of a gene encoding a synthetic antimicrobial peptideresults in inhibition of fungal growth in vitro and in planta

Transgenic tobacco plants producing the synthetic antimicrobial peptide D4E 1, encoded by a gene under the control of an enhanced cauliflower mosaic vi rus 35S RNA promoter, were obtained by Agrobacterium-mediated transformatio n. Successful transformation was demonstrated by PCR and Southern hybridiza tion analysis of tobacco DNAs. Expression of the synthetic D4E1 gene was sh own by RT-PCR of tobacco mRNA. Crude protein extracts from leaf tissue of t ransformed plants significantly reduced the number of fungal colonies arisi ng from germinating conidia of Aspergillus flavus and Verticillium dahliae by up to 75 and 99%, respectively, compared to extracts from plants transfo rmed with pBI121. Compared to negative controls, tobacco plants expressing the D4E1 gene showed greater levels of disease resistance in planta to the fungal pathogen, Colletotrichum destructivum, which causes anthracnose. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.