Independent Signaling Pathways Regulate Cellular Turgor during Hyperosmotic Stress and Appressorium-Mediated Plant Infection by Magnaporthe grisea
| Autor: | Nicholas J. Talbot, Nicholas Smirnoff, Jin-Rong Xu, Katherine P. Dixon |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Osmotic shock Molecular Sequence Data Turgor pressure Mutant Plant Science Biology Fungal Proteins chemistry.chemical_compound Osmotic Pressure Arabitol Magnaporthe grisea Amino Acid Sequence DNA Primers Appressorium Base Sequence Sequence Homology Amino Acid Osmotic concentration food and beverages Cell Biology Plants biology.organism_classification Cell biology Succinate Dehydrogenase Magnaporthe chemistry Biochemistry Mutation Mitogen-Activated Protein Kinases Signal transduction Research Article Signal Transduction |
| Zdroj: | The Plant Cell. 11:2045 |
| ISSN: | 1040-4651 |
| DOI: | 10.2307/3871096 |
| Popis: | The phytopathogenic fungus Magnaporthe grisea elaborates a specialized infection cell called an appressorium with which it mechanically ruptures the plant cuticle. To generate mechanical force, appressoria produce enormous hydrostatic turgor by accumulating molar concentrations of glycerol. To investigate the genetic control of cellular turgor, we analyzed the response of M. grisea to hyperosmotic stress. During acute and chronic hyperosmotic stress adaptation, M. grisea accumulates arabitol as its major compatible solute in addition to smaller quantities of glycerol. A mitogen-activated protein kinase–encoding gene OSM1 was isolated from M. grisea and shown to encode a functional homolog of HIGH-OSMOLARITY GLYCEROL1 ( HOG1 ), which encodes a mitogen-activated protein kinase that regulates cellular turgor in yeast. A null mutation of OSM1 was generated in M. grisea by targeted gene replacement, and the resulting mutants were sensitive to osmotic stress and showed morphological defects when grown under hyperosmotic conditions. M. grisea Δ osm1 mutants showed a dramatically reduced ability to accumulate arabitol in the mycelium. Surprisingly, glycerol accumulation and turgor generation in appressoria were unaltered by the Δ osm1 null mutation, and the mutants were fully pathogenic. This result indicates that independent signal transduction pathways regulate cellular turgor during hyperosmotic stress and appressorium-mediated plant infection. Consistent with this, exposure of M. grisea appressoria to external hyperosmotic stress induced OSM1 -dependent production of arabitol. |
| Databáze: | OpenAIRE |
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