title: Characterization and transcriptional regulation of Stachybotrys elegans mitogen-activated-protein kinase gene smkA following mycoparasitism and starvation conditions.
abstract: Mitogen-activated protein kinase (MAPK) signaling pathways play an important role in the development and conidiation of fungal pathogens on their hosts and the sensing of host-derived cues. Mycoparasitism is a fungus-fungus interaction comprising host-pathogen cross talk. Until now, only little information is available on the role of the MAPK signaling pathway during this interaction. Here, we report on the differential expression of a MAPK/ERK gene in the mycoparasite Stachybotrys elegans in response to direct parasitism of different vegetative structures of the plant pathogen Rhizoctonia solani (i.e., carbon-rich condition) and to nutrient starvation (i.e., carbon-poor condition). Western blot analysis against ERK1/2 highlighted an increase in their phosphorylated forms when S. elegans was grown under starvation condition compared to that detected in response to mycoparasitism. A higher abundance of phosphorylated ERK1/2 at the third day of interaction compared to that estimated under starvation condition was detected applying LC-MS/MS. At the transcriptional level, smkA, a YERK1 class member, was significantly induced in response to hyphal parasitism compared to parasitized sclerotia at 3, 4, and 5 days of interaction. However, under starvation condition, smkA levels were significantly induced after 7 days of growth. Southern blot analysis revealed that smkA is member of a small gene family. Collectively, these results suggest that smkA could be implicated in the mycoparasitic process in S. elegans as well as in stress-activated pathways. These results may be of wider significance in other fungus-fungus interactions.
authors.affiliation: Department of Plant Science, Macdonald Campus of McGill University, 21,111 Lakeshore Rd., Sainte-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
authors.forename: Rony
authors.initials: R
authors.lastname: Chamoun
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Aliferis
authors.forename: Suha H
authors.initials: SH
authors.lastname: Jabaji
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002853:Chromatography, Liquid; D015966:Gene Expression Regulation, Fungal; D013058:Mass Spectrometry; D056265:Microbial Interactions / Q000235:genetics*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D012232:Rhizoctonia / Q000502:physiology*; D016415:Sequence Alignment; D013191:Stachybotrys / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D020928:Mitogen-Activated Protein Kinases