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A member of the Fizzy-related family of APC activators is regulated by cAMP and is required at different stages of plant infection by Ustilago maydis.
- Source :
-
Journal of cell science [J Cell Sci] 2004 Aug 15; Vol. 117 (Pt 18), pp. 4143-56. - Publication Year :
- 2004
-
Abstract
- Here, we identified a new member of the Fizzy-related family of APC activators, Cru1, which is required for virulence in the corn smut fungus Ustilago maydis. We show that Cru1 promotes the degradation of B-type cyclins in U. maydis. Cells deficient in the Cru1 protein show defects in cell size, adaptation to nutritional conditions and cell separation. We propose that the phenotypes observed are a consequence of the inability of cru1 Delta cells to keep under control the levels of mitotic cyclins during G1. The levels of cru1 mRNA are controlled by nutritional conditions and cAMP levels, implicating the cAMP/protein kinase A pathway in the transmission of environmental conditions to the cell cycle. Cells deficient in Cru1 function are severely impaired in their ability to infect corn plants. This low rate of plant infection is caused by several defects. First, a low level of expression of the pheromone-encoding gene, mfa1, resulted in a low frequency of dikaryotic infective filament formation. Second, proliferation of fungal cells inside the plant is also affected, resulting in the inability to induce tumors in plants. Finally, the formation and germination of teliospores is also impaired. Our results support the hypothesis that virulence and cell cycle are connected in U. maydis. We propose that along the infection process, Cru1 is required to keep the appropriate G1 length necessary for the adaptation of fungal cells to host environment through the different stages of the plant infection.
- Subjects :
- Adaptation, Physiological physiology
Amino Acid Sequence
Anaphase-Promoting Complex-Cyclosome
Base Sequence
Cell Cycle Proteins genetics
Cell Cycle Proteins isolation & purification
Cell Cycle Proteins metabolism
Cell Proliferation
Cyclic AMP-Dependent Protein Kinases metabolism
Cyclins genetics
Cyclins metabolism
DNA, Complementary analysis
DNA, Complementary genetics
Fungal Proteins isolation & purification
Fungal Proteins metabolism
G2 Phase physiology
Gene Expression Regulation, Plant genetics
Molecular Sequence Data
Nitrogen metabolism
Pheromones genetics
Pheromones metabolism
RNA, Messenger metabolism
Ubiquitin-Protein Ligase Complexes metabolism
Ustilago cytology
Ustilago pathogenicity
Virulence
Cyclic AMP metabolism
Fungal Proteins genetics
Plant Diseases microbiology
Ubiquitin-Protein Ligase Complexes genetics
Ustilago genetics
Zea mays microbiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9533
- Volume :
- 117
- Issue :
- Pt 18
- Database :
- MEDLINE
- Journal :
- Journal of cell science
- Publication Type :
- Academic Journal
- Accession number :
- 15316079
- Full Text :
- https://doi.org/10.1242/jcs.01304