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Multiple avirulence paralogues in cereal powdery mildew fungi may contribute to parasite fitness and defeat of plant resistance.
- Source :
-
The Plant cell [Plant Cell] 2006 Sep; Vol. 18 (9), pp. 2402-14. Date of Electronic Publication: 2006 Aug 11. - Publication Year :
- 2006
-
Abstract
- Powdery mildews, obligate biotrophic fungal parasites on a wide range of important crops, can be controlled by plant resistance (R) genes, but these are rapidly overcome by parasite mutants evading recognition. It is unknown how this rapid evolution occurs without apparent loss of parasite fitness. R proteins recognize avirulence (AVR) molecules from parasites in a gene-for-gene manner and trigger defense responses. We identify AVR(a10) and AVR(k1) of barley powdery mildew fungus, Blumeria graminis f sp hordei (Bgh), and show that they induce both cell death and inaccessibility when transiently expressed in Mla10 and Mlk1 barley (Hordeum vulgare) varieties, respectively. In contrast with other reported fungal AVR genes, AVR(a10) and AVR(k1) encode proteins that lack secretion signal peptides and enhance infection success on susceptible host plant cells. AVR(a10) and AVR(k1) belong to a large family with >30 paralogues in the genome of Bgh, and homologous sequences are present in other formae speciales of the fungus infecting other grasses. Our findings imply that the mildew fungus has a repertoire of AVR genes, which may function as effectors and contribute to parasite virulence. Multiple copies of related but distinct AVR effector paralogues might enable populations of Bgh to rapidly overcome host R genes while maintaining virulence.
- Subjects :
- Amino Acid Sequence
Apoptosis physiology
Ascomycota genetics
Ascomycota metabolism
Cloning, Molecular
Evolution, Molecular
Fungal Proteins chemistry
Fungal Proteins genetics
Gene Dosage
Hordeum genetics
Immunity, Innate genetics
Models, Biological
Molecular Sequence Data
Plant Leaves genetics
Plant Leaves microbiology
Plant Proteins genetics
Sequence Alignment
Virulence Factors chemistry
Virulence Factors genetics
Ascomycota pathogenicity
Fungal Proteins physiology
Hordeum microbiology
Virulence Factors physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1040-4651
- Volume :
- 18
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- The Plant cell
- Publication Type :
- Academic Journal
- Accession number :
- 16905653
- Full Text :
- https://doi.org/10.1105/tpc.106.043307