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Heterologous Expression of Genes Mediating Enhanced Fungal Resistance in Transgenic Wheat

July 2001 , Volume 14 , Number  7
Pages  832 - 838

Klaus H. Oldach , Dirk Becker , and Horst Lörz

Institute for Applied Molecular Plant Biology, AMPII, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, Germany

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Accepted 26 February 2001.

Three cDNAs encoding the antifungal protein Ag-AFP from the fungus Aspergillus giganteus, a barley class II chitinase and a barley type I RIP, all regulated by the constitutive Ubiquitin1 promoter from maize, were expressed in transgenic wheat. In 17 wheat lines, stable integration and inheritance of one of the three transgenes has been demonstrated over four generations. The formation of powdery mildew (Erysiphe graminis f. sp. tritici) or leaf rust (Puccinia recondita f. sp. tritici) colonies was significantly reduced on leaves from afp or chitinase II- but not from rip I-expressing wheat lines compared with non-transgenic controls. The increased resistance of afp and chitinase II lines was dependent on the dose of fungal spores used for inoculation. Heterologous expression of the fungal afp gene and the barley chitinase II gene in wheat demonstrated that colony formation and, thereby, spreading of two important biotrophic fungal diseases is inhibited approximately 40 to 50% at an inoculum density of 80 to 100 spores per cm2.

© 2001 The American Phytopathological Society