scholarly journals TmkA, a Mitogen-Activated Protein Kinase of Trichoderma virens, Is Involved in Biocontrol Properties and Repression of Conidiation in the Dark

2003 ◽  
Vol 2 (3) ◽  
pp. 446-455 ◽  
Author(s):  
Prasun K. Mukherjee ◽  
Jagannathan Latha ◽  
Ruthi Hadar ◽  
Benjamin A. Horwitz
Keyword(s):  
Protein Kinase ◽  
Plant Pathogens ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Trichoderma Virens ◽  
Loss Of Function ◽  
Wild Type ◽  
Mapk Cascades ◽  
Mitogen Activated Protein

ABSTRACT Trichoderma virens is a mycoparasitic fungus used in biocontrol of soilborne plant pathogens. It inhibits or kills plant-pathogenic fungi through production of antifungal antibiotics and parasitism of hyphae and sclerotia. Conidiation, or the production of asexual spores, an inducible process triggered by light or nutrient stress, is an important trait in survival and also development of formulation products. In many fungi, signaling pathways, including mitogen-activated protein kinase (MAPK) cascades, have been implicated in parasitism of host plants as well as in the production of asexual spores. Here, we have studied the role of a MAPK gene, that for TmkA, in conidiation and antagonistic properties of a biocontrol strain of T. virens. Through single- and double-crossover recombination, we obtained three tmkA loss-of-function mutants. The TmkA transcript was not detectable in these mutants. The mutants conidiated in the dark, although photoinduction was normal and the light sensitivities of the wild type and the mutant were the same. The mutants had, overall, normal colony morphology, but their radial growth rate was reduced by about 16%, with no decrease in biomass production. Against Rhizoctonia solani hyphae, the knockout mutants exhibited mycoparasitic coiling and lysis of host hyphae similar to that of the wild type. The mutants, however, were less effective in colonizing the sclerotia of R. solani. On Sclerotium rolfsii, the MAPK loss-of-function mutants had reduced antagonistic properties in confrontation assays and failed to parasitize the sclerotia. TmkA-dependent and -independent pathways are thus involved in antagonism against different hosts. Finally, in contrast to the case for other filamentous fungi studied so far, signaling through a MAPK represses, rather than induces, asexual sporulation.

scholarly journals The pmk1-like mitogen-activated protein kinase from Lecanicillium (Verticillium) fungicola is not required for virulence on Agaricus bisporus

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1439-1447 ◽  
Author(s):  
Patrick D. Collopy ◽  
Richard C. Amey ◽  
Martin J. Sergeant ◽  
Michael P. Challen ◽  
Peter R. Mills ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Agaricus Bisporus ◽  
Plant Pathogens ◽  
Mapk Pathway ◽  
Pathogenic Fungi ◽  
Single Copy ◽  
Mitogen Activated Protein Kinase ◽  
Verticillium Fungicola ◽  
Fungal Plant Pathogens ◽  
Mitogen Activated Protein

In plant-pathogenic fungi, the pmk1 mitogen-activated protein kinase (MAPK) signalling pathway plays an essential role in regulating the development of penetration structures and the sensing of host-derived cues, but its role in other pathosystems such as fungal–fungal interactions is less clear. We report the use of a gene disruption strategy to investigate the pmk1-like MAPK, Lf pmk1 in the development of Lecanicillium fungicola (formerly Verticillium fungicola) infection on the cultivated mushroom Agaricus bisporus. Lf pmk1 was isolated using a degenerate PCR-based approach and was shown to be present in a single copy by Southern blot analysis. Quantitative RT-PCR showed the transcript to be fivefold upregulated in cap lesions compared with pure culture. Agrobacterium-mediated targeted disruption was used to delete a central portion of the Lf pmk1 gene. The resulting mutants showed normal symptom development as assessed by A. bisporus mushroom cap assays, sporulation patterns were normal and there were no apparent changes in overall growth rates. Our results indicate that, unlike the situation in fungal–plant pathogens, the pmk1-like MAPK pathway is not required for virulence in the fungal–fungal interaction between the L. fungicola pathogen and A. bisporus host. This observation may be of wider significance in other fungal–fungal and/or fungal–invertebrate interactions.

scholarly journals Role of Two G-Protein Alpha Subunits, TgaA and TgaB, in the Antagonism of Plant Pathogens by Trichoderma virens

2004 ◽  
Vol 70 (1) ◽  
pp. 542-549 ◽  
Author(s):  
Prasun K. Mukherjee ◽  
Jagannathan Latha ◽  
Ruthi Hadar ◽  
Benjamin A. Horwitz
Keyword(s):  
G Protein ◽  
Plant Pathogens ◽  
Sclerotium Rolfsii ◽  
Trichoderma Virens ◽  
Loss Of Function ◽  
Wild Type ◽  
Protein Subunit ◽  
Α Subunit ◽  
Germ Tubes

ABSTRACT G-protein α subunits are involved in transmission of signals for development, pathogenicity, and secondary metabolism in plant pathogenic and saprophytic fungi. We cloned two G-protein α subunit genes, tgaA and tgaB, from the biocontrol fungus Trichoderma virens. tgaA belongs to the fungal Gαi class, while tgaB belongs to the class defined by gna-2 of Neurospora crassa. We compared loss-of-function mutants of tgaA and tgaB with the wild type for radial growth, conidiation, germination of conidia, the ability to overgrow colonies of Rhizoctonia solani and Sclerotium rolfsii in confrontation assays, and the ability to colonize the sclerotia of these pathogens in soil. Both mutants grew as well as the wild type, sporulated normally, did not sporulate in the dark, and responded to blue light by forming a conidial ring. The tgaA mutants germinated by straight unbranched germ tubes, while tgaB mutants, like the wild type, germinated by wavy and highly branched germ tubes. In confrontation assays, both tgaA and tgaB mutants and the wild type overgrew, coiled, and lysed the mycelia of R. solani, but tgaA mutants had reduced ability to colonize S. rolfsii colonies. In the soil plate assay, both mutants parasitized the sclerotia of R. solani, but tgaA mutants were unable to parasitize the sclerotia of S. rolfsii. Thus, tgaA is involved in antagonism against S. rolfsii, but neither G protein subunit is involved in antagonism against R. solani. T. virens, which has a wide host range, thus employs a G-protein pathway in a host-specific manner.

scholarly journals Trichoderma Mitogen-Activated Protein Kinase Signaling Is Involved in Induction of Plant Systemic Resistance

2005 ◽  
Vol 71 (10) ◽  
pp. 6241-6246 ◽  
Author(s):  
Ada Viterbo ◽  
Michal Harel ◽  
Benjamin A. Horwitz ◽  
Ilan Chet ◽  
Prasun K. Mukherjee
Keyword(s):  
Protein Kinase ◽  
Pseudomonas Syringae ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Plant Roots ◽  
Systemic Resistance ◽  
Loss Of Function ◽  
Mitogen Activated Protein

ABSTRACT The role of a mitogen-activated protein kinase (MAPK) TmkA in inducing systemic resistance in cucumber against the bacterial pathogen Pseudomonas syringae pv. lacrymans was investigated by using tmkA loss-of-function mutants of Trichoderma virens. In an assay where Trichoderma spores were germinated in proximity to cucumber roots, the mutants were able to colonize the plant roots as effectively as the wild-type strain but failed to induce full systemic resistance against the leaf pathogen. Interactions with the plant roots enhanced the level of tmkA transcript in T. virens and its homologue in Trichoderma asperellum. At the protein level, we could detect the activation of two forms reacting to the phospho-p44/42 MAPK antibody. Biocontrol experiments demonstrated that the tmkA mutants retain their biocontrol potential against Rhizoctonia solani in soil but are not effective against Sclerotium rolfsii in reducing disease incidence. Our results show that, unlike in many plant-pathogen interactions, Trichoderma TmkA MAPK is not involved in limited root colonization. Trichoderma, however, needs MAPK signaling in order to induce full systemic resistance in the plant.

scholarly journals Exercise-induced mitogen-activated protein kinase signalling in skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Yun Chau Long ◽  
Ulrika Widegren ◽  
Juleen R. Zierath
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Cascades ◽  
Extracellular Signal ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Exercise Induced ◽  
Response To Exercise

Exercise training improves glucose homeostasis through enhanced insulin sensitivity in skeletal muscle. Muscle contraction through physical exercise is a physiological stimulus that elicits multiple biochemical and biophysical responses and therefore requires an appropriate control network. Mitogen-activated protein kinase (MAPK) signalling pathways constitute a network of phosphorylation cascades that link cellular stress to changes in transcriptional activity. MAPK cascades are divided into four major subfamilies, including extracellular signal-regulated kinases 1 and 2, p38 MAPK, c-Jun NH2-terminal kinase and extracellular signal-regulated kinase 5. The present review will present the current understanding of parallel MAPK signalling in human skeletal muscle in response to exercise and muscle contraction, with an emphasis on identifying potential signalling mechanisms responsible for changes in gene expression.

scholarly journals TRAF6-Dependent Mitogen-Activated Protein Kinase Activation Differentially Regulates the Production of Interleukin-12 by Macrophages in Response to Toxoplasma gondii

2004 ◽  
Vol 72 (10) ◽  
pp. 5662-5667 ◽  
Author(s):  
Nicola J. Mason ◽  
Jim Fiore ◽  
Takashi Kobayashi ◽  
Katherine S. Masek ◽  
Yongwon Choi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Toxoplasma Gondii ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Interleukin 12 ◽  
Wild Type ◽  
Kinase Activation ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

ABSTRACT The production of interleukin-12 (IL-12) is critical to the development of innate and adaptive immune responses required for the control of intracellular pathogens. Many microbial products signal through Toll-like receptors (TLR) and activate NF-κB family members that are required for the production of IL-12. Recent studies suggest that components of the TLR pathway are required for the production of IL-12 in response to the parasite Toxoplasma gondii; however, the production of IL-12 in response to this parasite is independent of NF-κB activation. The adaptor molecule TRAF6 is involved in TLR signaling pathways and associates with serine/threonine kinases involved in the activation of both NF-κB and mitogen-activated protein kinase (MAPK). To elucidate the intracellular signaling pathways involved in the production of IL-12 in response to soluble toxoplasma antigen (STAg), wild-type and TRAF6−/− mice were inoculated with STAg, and the production of IL-12(p40) was determined. TRAF6−/− mice failed to produce IL-12(p40) in response to STAg, and TRAF6−/− macrophages stimulated with STAg also failed to produce IL-12(p40). Studies using Western blot analysis of wild-type and TRAF6−/− macrophages revealed that stimulation with STAg resulted in the rapid TRAF6-dependent phosphorylation of p38 and extracellular signal-related kinase, which differentially regulated the production of IL-12(p40). The studies presented here demonstrate for the first time that the production of IL-12(p40) in response to toxoplasma is dependent upon TRAF6 and p38 MAPK.

scholarly journals Protein Kinase A Operates a Molecular Switch That Governs Yeast Pseudohyphal Differentiation

2002 ◽  
Vol 22 (12) ◽  
pp. 3981-3993 ◽  
Author(s):  
Xuewen Pan ◽  
Joseph Heitman
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Cascades ◽  
Mitogen Activated Protein ◽  
Eukaryotic Organisms ◽  
Pseudohyphal Differentiation ◽  
Developmental Switch ◽  
Kinase A

ABSTRACT The yeast Saccharomyces cerevisiae undergoes a dimorphic filamentous transition in response to nutrient cues that is affected by both mitogen-activated protein kinase and cyclic AMP-protein kinase A signaling cascades. Here two transcriptional regulators, Flo8 and Sfl1, are shown to be the direct molecular targets of protein kinase A. Flo8 and Sfl1 antagonistically control expression of the cell adhesin Flo11 via a common promoter element. Phosphorylation by the protein kinase A catalytic subunit Tpk2 promotes Flo8 binding and activation of the Flo11 promoter and relieves repression by prohibiting dimerization and DNA binding by Sfl1. Our studies illustrate in molecular detail how protein kinase A combinatorially effects a key developmental switch. Similar mechanisms may operate in pathogenic fungi and more complex multicellular eukaryotic organisms.

scholarly journals A single amino acid substitution (N297A) in the conserved NPXXY sequence of the human N-formyl peptide receptor results in inhibition of desensitization and endocytosis, and a dose-dependent shift in p42/44 mitogen-activated protein kinase activation and chemotaxis

2000 ◽  
Vol 352 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Jeannie M. GRIPENTROG ◽  
Algirdas J. JESAITIS ◽  
Heini M. MIETTINEN
Keyword(s):  
Protein Kinase ◽  
Transmembrane Domain ◽  
Mitogen Activated Protein Kinase ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Mitogen Activated Protein ◽  
Dose Dependent Increase ◽  
Dose Dependent

The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis and stimulates the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase pathway. We have examined the functional effects of substitutions of a conserved aspartic acid residue in the second transmembrane domain (D71A) and of residues in the conserved NPXXY motif in the seventh transmembrane domain (N297A and Y301A). These mutated receptors, expressed in Chinese hamster ovary (CHO) cells, bind ligand with affinities similar to wild-type FPR, but the D71A mutant is uncoupled from G-protein [Miettinen, Mills, Gripentrog, Dratz, Granger and Jesaitis (1997) J. Immunol 159, 4045–4054]. In the present study, we show that both the D71A and N297A mutations resulted in defective endocytosis. The N297A substitution also prevented desensitization, as determined by intracellular calcium mobilization by sequential stimulation with ligand. In chemotaxis assays, the N297A mutation resulted in cell migration towards gradients of up to 100nM N-formyl-methionyl-leucyl-phenylalanine (fMLF), whereas cells expressing the wild-type FPR and the Y301A mutant were no longer chemotactically responsive at 10–100nM fMLF. Maximal activation of p42/44 MAPK occurred in CHO cells expressing wild-type FPR at 10nM–100nM fMLF, whereas cells expressing the N297A mutant showed a dose-dependent increase in the amount of phosphorylated p42/44 MAPK up to 1–10µM fMLF. Since the MAPK kinase inhibitor PD98059 blocked fMLF-induced chemotaxis, our results suggest that the dose-dependent increase in p42/44 MAPK activation may correlate with the increased chemotactic migration of N297A transfectants at 10nM–100nM fMLF.

scholarly journals Genome-wide identification of MAPKKK genes and their response to phytoplasma stress in Chinese jujube (Ziziphus jujuba Mill.)

2019 ◽  
Author(s):  
ZhiGuo Liu ◽  
Lixin Wang ◽  
Chaoling Xue ◽  
Yuetong Chu ◽  
Weilin Gao ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Expression Profiles ◽  
Duplication Event ◽  
Kinase Domain ◽  
Mitogen Activated Protein Kinase ◽  
Chinese Jujube ◽  
Mapk Cascades ◽  
Mitogen Activated Protein ◽  
Phytoplasma Infection ◽  
Gene Structures

Abstract Backgrounds Mitogen activated protein kinase (MAPK) cascades play vital roles in signal transduction in response to various biotic and abiotic stresses. In the previous study we have identified 10 ZjMAPKs and 5 ZjMAPKKs in Chinese jujube genome and found some crucial members of ZjMAPKs and ZjMAPKKs might function importantly in the process of phytoplasma infection. But how these ZjMAPKKs were modulated by ZjMAPKKKs during this process is still elusive and little information is known about the MAPKKKs in Chinese jujube. Results In the current study, 56 ZjMAPKKKs were identified in the jujube genome and all of them contain the key S-TKc (serine/threonine protein kinase) domain which distributed in all 12 chromosomes. Phylogenetic analysis showed that these ZjMAPKKKs could be classified into two subfamilies, of which 41 belonged to Raf, and 15 to MEKK subfamily. In addition, the ZjMAPKKKs in each subfamily share the same conserved motifs and gene structures, one pair of ZjMAPKKKs (15/16) was the only tandem duplication event on Chromosome 5. Furthermore, the expression profiles of these MAPKKKs in response to phytoplasma disease were investigated by qPCR. In the three main infected tissues (witches’ broom leaves, phyllody leaves, apparent normal leaves), the ZjMAPKKK26 and 45 were significantly up regulated and the ZjMAPKKK3, 43 and 50 were down regulated. While the ZjMAPKKK4, 10, 25 and 44 were significant highly induced in the sterile cultivated tissues infected by phytoplasma, and the ZjMAPKKK7, 30, 35, 37, 40, 41, 43 and 46 were significantly down regulated. Conclusions The identification and classification analysis of ZjMAPKKKs was firstly reported and some key individual ZjMAPKKKs genes might play essential roles in response to phytoplasma infection. This could provide initial understanding for the mechanism that how the ZjMAPKKKs were involved in jujube - phytoplasma infection.

scholarly journals RICK Promotes Inflammation and Lethality after Gram-Negative Bacterial Infection in Mice Stimulated with Lipopolysaccharide

2009 ◽  
Vol 77 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Jong-Hwan Park ◽  
Yun-Gi Kim ◽  
Gabriel Núñez
Keyword(s):  
Protein Kinase ◽  
Regulatory Protein ◽  
Mitogen Activated Protein Kinase ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Proinflammatory Response ◽  
Interacting Protein ◽  
Gram Negative ◽  
Mitogen Activated Protein

ABSTRACT RICK (receptor-interacting protein-like interacting caspase-like apoptosis regulatory protein kinase), a serine-threonine kinase, functions downstream of the pattern recognition receptors Nod1 and Nod2 to mediate NF-κB and mitogen-activated protein kinase (MAPK) activation in response to specific microbial stimuli. However, the function of RICK in the recognition and host defense of gram-negative bacteria remains poorly understood. We report here that infection of wild-type and RICK-deficient macrophages with Pseudomonas aeruginosa and Escherichia coli elicited comparable activation of NF-κB and MAPKs as well as secretion of proinflammatory cytokines. However, production of interleukin 6 (IL-6) and IL-1β induced by these gram-negative bacteria was impaired in RICK-deficient macrophages when the cells had previously been stimulated with lipopolysaccharide (LPS) or E. coli. The diminished proinflammatory response of RICK-deficient macrophages to bacteria was associated with reduced activation of NF-κB and MAPKs. Importantly, mutant mice deficient in RICK were less susceptible than wild-type mice to P. aeruginosa infection when the animals had previously been stimulated with LPS. The reduced lethality of RICK-deficient mice infected with P. aeruginosa was independent of pathogen clearance but was associated with diminished production of proinflammatory molecules in vivo. These results demonstrate that RICK contributes to the induction of proinflammatory responses and susceptibility to gram-negative bacteria after exposure to LPS, a condition that is associated with reduced Toll-like receptor signaling.

Sign in / Sign up

Export Citation Format

Share Document