1. PsMPK7, a stress-associated mitogen-activated protein kinase (MAPK) in Phytophthora sojae, is required for stress tolerance, reactive oxygenated species detoxification, cyst germination, sexual reproduction and infection of soybean.
- Author
-
Gao J, Cao M, Ye W, Li H, Kong L, Zheng X, and Wang Y
- Subjects
- Adaptation, Physiological drug effects, Extracellular Space enzymology, Gene Expression Regulation drug effects, Gene Silencing drug effects, Laccase metabolism, Mitogen-Activated Protein Kinases genetics, Mycelium drug effects, Mycelium growth & development, Osmosis drug effects, Oxidation-Reduction drug effects, Phytophthora drug effects, Plant Diseases microbiology, Plants, Genetically Modified, Reproduction drug effects, Seedlings microbiology, Sodium Chloride pharmacology, Glycine max drug effects, Glycine max genetics, Spores drug effects, Transformation, Genetic drug effects, Mitogen-Activated Protein Kinases metabolism, Phytophthora enzymology, Phytophthora pathogenicity, Reactive Oxygen Species metabolism, Glycine max microbiology, Spores growth & development, Stress, Physiological drug effects
- Abstract
The sensing of stress signals and their transduction into appropriate responses are crucial for the adaptation, survival and infection of phytopathogenic fungi and oomycetes. Amongst evolutionarily conserved pathways, mitogen-activated protein kinase (MAPK) cascades function as key signal transducers that use phosphorylation to convey information. In this study, we identified a gene, designated PsMPK7, one of 14 predicted genes encoding MAPKs in Phytophthora sojae. PsMPK7 was highly transcribed in each tested stage, but was up-regulated in the zoospore, cyst and cyst germination stages. Silencing of PsMPK7 affected the growth of germinated cysts, oospore production and the pathogenicity of soybean. PsMPK7 transcription was induced by stresses from sorbitol, NaCl and hydrogen peroxide. Transformants in which PsMPK7 expression was silenced (PsMPK7-silenced) were significantly more sensitive to osmotic and oxidative stress. Aniline blue and diaminobenzidine staining revealed that the silenced lines did not suppress the host reactive oxygen species (ROS) burst, indicating that either the inoculated plants activated stronger defence responses to the transformants and/or the PsMPK7-silenced transformants failed to overcome plant defences. In addition, extracellular secretion of laccase decreased in the silenced lines. Overall, our results indicate that the PsMPK7 gene encodes a stress-associated MAPK in P. sojae that is important not only for responses to various stresses, but also for ROS detoxification, cyst germination, sexual oospore production and infection of soybean., (© 2014 BSPP AND JOHN WILEY & SONS LTD.)
- Published
- 2015
- Full Text
- View/download PDF