Differential induction of the Arabidopsis thaliana Thi2.1 gene by Fusarium oxysporum f. sp. matthiolae.
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 beta-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.
Epple
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Swiss Federal Institute of Technology (ETH), ETH-Zentrum, Zurich, Switzerland.
Vignutelli
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Apel
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Bohlmann
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D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology; D005670:Fusarium / Q000254:growth & development / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant; D005966:Glucuronidase / Q000235:genetics; D030821:Plants, Genetically Modified
D005966:Glucuronidase