Characterization and complementation of a Fus3/Kss1 type MAPK from Tuber borchii, TBMK

Abstract

Mitogen-activated protein kinases (MAPK) are used by organisms to transduce extra cellular signals from the environment in cellular events such as proliferation and differentiation. In the present study, we have characterized the first MAPK from the ectomycorrhizal fungus Tuber borchii (TBMK) which belongs to the YERK1 (yeast extra cellular regulated kinase) subfamily. TBMK is present as a single copy in the genome and the codified protein was phosphorylated during the interaction with the host plant, Tilia americana. Complementation studies showed that TBMK restores pheromone signaling in Saccharomyces cerevisiae and partially restores invasive growth of Fusarium oxysporum that lack the fmk1 gene. This suggests a protein kinase activity and its involvement in the infection processes. Hence, TBMK could play an important role during the pre-symbiotic phase of T. borchii with its host plant in the modulation of genes necessary for the establishment of symbiosis leading to the synthesis of functional ectomycorrhizae.

Molecular Characterization of a Fus3/Kss1 Type MAPK from Puccinia striiformis f. sp. tritici, PsMAPK1

“…It is likely that PsMAPK1 plays a critical role in the regulation of penetration peg formation by the haustorium mother cell and differentiation of haustoria in plant cells in Pst . In addition, similar to symbiosis of Tuber borchii , Pst may use this MAPK pathway for its biotrophic growth in planta [34] .…”

Mitogen-Activated Protein Kinase Signaling in Plant-Interacting Fungi: Distinct Messages from Conserved Messengers

“…In the ectomycorrhizal fungus Tuber borchii, the Kss1/Fus3-type MAPK TBMK (here renamed Tbo-Kss1 according to our unified nomenclature; see below) becomes phosphorylated during interaction of the fungus with its host tree, Tilia americana (Menotta et al, 2006). Interestingly, ectopic expression of this MAPK in F. oxysporum strains lacking Fmk1 (here renamed Fox-Kss1; see below) partially restores their ability to grow invasively (Menotta et al, 2006). This suggests that MAPK signaling could play an important role during the presymbiotic colonization phase, perhaps by modulating expression of target genes necessary to allow host infection and establishment of functional ectomycorrhizae.…”

Mitogen-Activated Protein Kinase Pathways and Fungal Pathogenesis

“…A FMK1 homolog from Tuber borchii is phosphorylated during plant colonization and partially restores invasive growth of the fmk1 mutant. Therefore, the same MAPK pathway may regulate the establishment of symbiosis and ectomycorrhizae (95).…”