Overlapping and distinct functions of two Trichoderma virens MAP kinases in cell-wall integrity, antagonistic properties and repression of conidiation

Trichoderma: sensing the environment for survival and dispersal

“…There are three classes of MAPK pathway in filamentous ascomycetes: the pathogenicity MAPK typified by Pmk1 of Magnaporthe oryzae, the Slt2 MAPK pathway involved in maintenance of cell-wall integrity, and the Hog1 pathway involved in stress responses (Kumar et al, 2010). All three pathways are present in Trichoderma spp.…”

“…Mutants in the corresponding MAPK from T. atroviride (Tmk1) produce abundant conidia in a light-independent manner (Reithner et al, 2007). In addition, T. virens tmkB mutants exhibit reduced growth and constitutive conidiation in the dark (Kumar et al, 2010). Thus, the first two classes of MAPK in Trichoderma seem to repress conidiation.…”

Insights into Signaling Pathways of Antagonistic Trichoderma Species

“…Unlike in many plant-pathogen interactions though, Trichoderma TmkA turned out to be not essential for hyphal growth on the root surface and penetration of the epidermal cells (Viterbo et al, 2005). G. BIOCONTROL AND PLANT GROWTH PROMOTION For the T. virens TmkB MAP kinase, a homolog of the yeast cell-wall integrity MAPK Slt2, partially overlapping roles with TmkA have been found (Kumar et al, 2010). ΔtmkB mutants had a reduced ability to overgrow S. rolfsii, while they retained their mycoparasitic activity against R. solani and Pythium spp., a phenotype similar to that of ΔtmkA mutants.…”

“…In addition, tmkB mutants displayed cell-wall integrity defects and autolytic behavior on PDA (potato dextrose agar) but no autolysis was seen on synthetic Vogels minimal medium (Kumar et al, 2010). Both, TmkA and TmkB, thus seem to repress conidiation in T. virens which might be mediated by a joint activation of downstream targets.…”

The Mitogen-Activated Protein Kinase Signal Transduction Pathways in Alternaria Species

“…In A. alternata, spraying inoculation with conidial suspension of the wild type or the A. alternata Slt2 mutant induced different symptoms on tangerine Minneola leaves. The lesions AAM13670 Vegetative growth, female fertility, plant infection, cell wall integrity (Hou et al, 2002 M. grisea Mps1 AAC63682 Pathogenicity, cell wall integrity, pathogen penetration, appressorium formation, conidiation, female fertility, (Xu et al, 1998) M. graminicola MgSlt2 AAY98511 Pathogenicity, fungicide resisitance, pycnidia formation, virulence, melanisation (Mehrabi et al, 2006a) S. cerevisiae Slt2 NP_011895 Cell wall remodeling (Gustin et al, 1998) T. virens TmkB ACD88751 Cell wall integrity, conidiation, vegetative growth, melanin biosynthesis (Kumar et al, 2010) induced by the Slt2 mutant were smaller and progressed more slowly than that induced by the wild type strain, which may be a comprehensive result of reduced production of ACT (Alternaria citri tangerine pathotype) -toxin, growth retardation and deformation of hyphal extension (Yago et al, 2011). Disruption of AbSlt2 gene also reduced the virulence of A. brassicicola.…”