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Differential Induction of the Arabidopsis thaliana Thi2.1 Gene by Fusarium oxysporum f. sp. matthiolae

June 1998 , Volume 11 , Number  6
Pages  523 - 529

Petra Epple , Alberto Vignutelli , Klaus Apel , and Holger Bohlmann

Swiss Federal Institute of Technology (ETH), Institute for Plant Sciences, ETH-Zentrum, Universitätstrasse 2, LFW D.58, CH-8092 Zurich, Switzerland

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Accepted 7 February 1998.

The Arabidopsis thaliana Thi2.1 gene is inducible by necrotrophic fungi through a signal transduction pathway different from that for pathogenesis-related (PR) proteins. We have identified three ecotypes that are susceptible (Col-2, Ler, and Ws) and two ecotypes that are resistant (Mt-0 and Uk-4) to spray inoculation with Fusarium oxysporum f. sp. matthiolae. The Thi2.1 transcript level after infection correlates with resistance, being 5 to 10 times higher in the resistant than in the susceptible ecotypes. The β-glucuronidase (GUS) expression of a Thi2.1-promoter-uidA fusion (with a promoter derived from Col-2) is on the average almost 10 times higher in the Uk-4 background than in the Col-2 background. This confirms the results obtained by Northern (RNA) blots and indicates that Uk-4, and probably other resistant ecotypes too, might have a more sensitive recognition system for F. oxysporum f. sp. matthiolae or might have a signal transduction system that gives a higher amplification of the original recognition signal. Our results suggest a role of the Thi2.1 gene in resistance against F. oxysporum f. sp. matthiolae and perhaps other necrotrophic fungi.

Additional keywords: antimicrobial, cysteine-rich.

© 1998 The American Phytopathological Society