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Polygalacturonase is a pathogenicity factor in the Claviceps purpurea/rye interaction
Birgitt Oeser1, Patrick M Heidrich, Ulrike Müller
1Institut für Botanik, Westfälische Wilhelms-Universität, Schlossgarten 3, Münster, Germany.
Fungal Genetics and Biology : FG & B
|July 24, 2002
Summary
Claviceps purpurea uses two endopolygalacturonase genes (cppg1/cppg2) to infect rye. Deleting these genes made the fungus nearly nonpathogenic, identifying these enzymes as key virulence factors.
Area of Science:
- Plant pathology
- Fungal genetics
- Biochemistry
Background:
- Claviceps purpurea is a grass and cereal pathogen that targets young ovaries.
- Intercellular growth of C. purpurea involves pectin degradation.
- Two endopolygalacturonase genes (cppg1/cppg2) are expressed during infection.
Purpose of the Study:
- To functionally analyze the roles of cppg1 and cppg2 in C. purpurea pathogenicity.
- To identify specific pathogenicity factors in the C. purpurea/Secale cereale interaction.
Main Methods:
- Gene-replacement strategy to create double mutants lacking cppg1 and cppg2.
- Assessment of vegetative properties of the mutants.
- Pathogenicity assays on rye (Secale cereale).
- Complementation of mutants with wild-type gene copies.
Main Results:
- Mutants lacking both cppg1 and cppg2 showed no defects in vegetative growth.
- These double mutants were significantly impaired in pathogenicity on rye, becoming nearly nonpathogenic.
- Complementation restored full pathogenicity, confirming the role of cppg1 and cppg2.
Conclusions:
- The endopolygalacturonases encoded by cppg1 and cppg2 are essential pathogenicity factors for C. purpurea infecting rye.
- This study provides the first unequivocally identified virulence factors in the C. purpurea/Secale cereale pathosystem.