scholarly journals The Colletotrichum lagenarium MAP Kinase Gene CMK1 Regulates Diverse Aspects of Fungal Pathogenesis

2000 ◽  
Vol 13 (4) ◽  
pp. 374-383 ◽  
Author(s):  
Yoshitaka Takano ◽  
Taisei Kikuchi ◽  
Yasuyuki Kubo ◽  
John E. Hamer ◽  
Kazuyuki Mise ◽  
...  
Keyword(s):  
Map Kinase ◽  
Host Plant ◽  
Magnaporthe Grisea ◽  
Phytopathogenic Fungi ◽  
Infection Process ◽  
Conidial Germination ◽  
Gene Encoding ◽  
Kinase Gene ◽  
Colletotrichum Lagenarium ◽  
Mitogen Activated Protein

The infection process of Colletotrichum lagenarium, the causal agent of cucumber anthracnose disease, involves several key steps: germination; formation of melanized appressoria; appressorial penetration; and subsequent invasive growth in host plants. Here we report that the C. lagenarium CMK1 gene encoding a mitogen-activated protein (MAP) kinase plays a central role in these infection steps. CMK1 can complement appressorium formation of the Pmk1 MAP kinase mutant of Magnaporthe grisea. Deletion of CMK1 causes reduction of conidiation and complete lack of pathogenicity to the host plant. Surprisingly, in contrast to M. grisea pmk1 mutants, conidia of cmk1 mutants fail to germinate on both host plant and glass surfaces, demonstrating that the CMK1 MAP kinase regulates conidial germination. However, addition of yeast extract rescues germination, indicating the presence of a CMK1-independent pathway for regulation of conidial germination. Germinating conidia of cmk1 mutants fail to form appressoria and the mutants are unable to grow invasively in the host plant. This strongly suggests that MAP kinase signaling pathways have general significance for infection structure formation and pathogenic growth in phytopathogenic fungi. Furthermore, three melanin genes show no or slight expression in the cmk1 mutant when conidia fail to germinate, suggesting that CMK1 plays a role in gene expression required for appressorial melanization.

scholarly journals The Biotrophic, Non-Appressorium-Forming Grass Pathogen Claviceps purpurea Needs a Fus3/Pmk1 Homologous Mitogen-Activated Protein Kinase for Colonization of Rye Ovarian Tissue

2002 ◽  
Vol 15 (4) ◽  
pp. 303-312 ◽  
Author(s):  
G. Mey ◽  
B. Oeser ◽  
M. H. Lebrun ◽  
P. Tudzynski
Keyword(s):  
Map Kinase ◽  
Magnaporthe Grisea ◽  
Ovarian Tissue ◽  
Gene Replacement ◽  
Mitogen Activated Protein Kinase ◽  
Claviceps Purpurea ◽  
Obvious Effect ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Detail Loss

Claviceps purpurea is a common pathogen of a wide range of grasses and cereals that is able to establish a stable, balanced interaction with its host plant and is considered a biotroph. It does not form special penetration structures such as appressoria. To study the signaling processes involved in this special host-pathogen interaction, we have cloned a gene, cpmk1, encoding a mitogen-activated protein (MAP) kinase that shows significant homology to Fus3 of Saccharomyces cerevisiae and to pmk1 of Magnaporthe grisea. Using a gene-replacement approach, we isolated a Δcpmk1 mutant and characterized it in detail. Loss of CPMK1 has no obvious effect on vegetative properties (such as growth rate, morphology, and conidia formation); however, infection tests on rye show that the mutant is unable to colonize rye tissue, i.e., it appears to be completely nonpathogenic. Complementation of the mutant with a wild-type copy of cpmk1 fully restores its pathogenicity, confirming that this MAP kinase is essential for infection of rye by C. purpurea. Transformation of the Δpmk1 mutant of M. grisea with a complete copy of cpmk1 (including the C. purpurea promoter) fully restored its ability to form appressoria and its pathogenicity on barley. Although both fungi drastically differ in their pathogenic strategies, this result indicates that the signal pathway involving CPMK1 is highly conserved.

scholarly journals BWMK1, a Novel MAP Kinase Induced by Fungal Infection and Mechanical Wounding in Rice

1999 ◽  
Vol 12 (12) ◽  
pp. 1064-1073 ◽  
Author(s):  
Chaozu He ◽  
Steven Haw Tien Fong ◽  
Daichang Yang ◽  
Guo-Liang Wang
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Magnaporthe Grisea ◽  
Mechanical Wounding ◽  
C Terminus ◽  
Acid Protein ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Rice Leaves ◽  
Activation Motif

The activation of the mitogen-activated protein (MAP) kinases by different environmental stresses has been previously observed in several dicot plant species. Here, we report the isolation of a novel MAP kinase in rice that is induced during infection by the blast fungus Magnaporthe grisea or upon mechanical wounding. The gene is designated as BWMK1 for blast- and wound-induced MAP kinase. The cDNA of BWMK1 was isolated from rice leaves challenged by the blast pathogen. Transcripts of the corresponding gene accumulated in rice leaves 4 h after blast inoculation and 30 min after mechanical wounding. This gene encodes a 506 amino acid protein that contains a new dual-phosphorylation activation motif TDY and about 150 unique amino acids on its C terminus. In-gel kinase activity and immunoprecipitation assays confirmed that BWMK1 is a functional MAP kinase. These results show that BWMK1 is a new member of the plant MAP kinase family and may mediate both defense and wound signaling in rice.

scholarly journals The BMP1 Gene Is Essential for Pathogenicity in the Gray Mold Fungus Botrytis cinerea

2000 ◽  
Vol 13 (7) ◽  
pp. 724-732 ◽  
Author(s):  
Li Zheng ◽  
Mathew Campbell ◽  
Jennifer Murphy ◽  
Stephen Lam ◽  
Jin-Rong Xu
Keyword(s):  
Growth Rate ◽  
Map Kinase ◽  
Botrytis Cinerea ◽  
Magnaporthe Grisea ◽  
Pathogenic Fungi ◽  
Gray Mold ◽  
Necrotrophic Pathogen ◽  
Kinase Gene ◽  
Plant Infection ◽  
Mold Fungus

In Magnaporthe grisea, a well-conserved mitogen-activated protein (MAP) kinase gene, PMK1, is essential for fungal pathogenesis. In this study, we tested whether the same MAP kinase is essential for plant infection in the gray mold fungus Botrytis cinerea, a necrotrophic pathogen that employs infection mechanisms different from those of M. grisea. We used a polymerase chain reaction-based approach to isolate MAP kinase homologues from B. cinerea. The Botrytis MAP kinase required for pathogenesis (BMP) MAP kinase gene is highly homologous to the M. grisea PMK1. BMP1 is a single-copy gene. bmp1 gene replacement mutants produced normal conidia and mycelia but were reduced in growth rate on nutrient-rich medium. bmp1 mutants were nonpathogenic on carnation flowers and tomato leaves. Re-introduction of the wild-type BMP1 allele into the bmp1 mutant restored both normal growth rate and pathogenicity. Further studies indicated that conidia from bmp1 mutants germinated on plant surfaces but failed to penetrate and macerate plant tissues. bmp1 mutants also appeared to be defective in infecting through wounds. These results indicated that BMP1 is essential for plant infection in B. cinerea, and this MAP kinase pathway may be widely conserved in pathogenic fungi for regulating infection processes.

scholarly journals Functional characterization of the MKC1 gene of Candida albicans, which encodes a mitogen-activated protein kinase homolog related to cell integrity.

1995 ◽  
Vol 15 (4) ◽  
pp. 2197-2206 ◽  
Author(s):  
F Navarro-García ◽  
M Sánchez ◽  
J Pla ◽  
C Nombela
Keyword(s):  
Candida Albicans ◽  
Map Kinase ◽  
Map Kinases ◽  
Functional Characterization ◽  
Mitogen Activated Protein Kinase ◽  
Lytic Enzyme ◽  
Phenotypic Traits ◽  
Kinase Gene ◽  
Enzyme Preparations ◽  
Mitogen Activated Protein

Mitogen-activated protein (MAP) kinases represent a group of serine/threonine protein kinases playing a central role in signal transduction processes in eukaryotic cells. Using a strategy based on the complementation of the thermosensitive autolytic phenotype of slt2 null mutants, we have isolated a Candida albicans homolog of Saccharomyces cerevisiae MAP kinase gene SLT2 (MPK1), which is involved in the recently outlined PKC1-controlled signalling pathway. The isolated gene, named MKC1 (MAP kinase from C. albicans), coded for a putative protein, Mkc1p, of 58,320 Da that displayed all the characteristic domains of MAP kinases and was 55% identical to S. cerevisiae Slt2p (Mpk1p). The MKC1 gene was deleted in a diploid Candida strain, and heterozygous and homozygous strains, in both Ura+ and Ura- backgrounds, were obtained to facilitate the analysis of the function of the gene. Deletion of the two alleles of the MKC1 gene gave rise to viable cells that grew at 28 and 37 degrees C but, nevertheless, displayed a variety of phenotypic traits under more stringent conditions. These included a low growth yield and a loss of viability in cultures grown at 42 degrees C, a high sensitivity to thermal shocks at 55 degrees C, an enhanced susceptibility to caffeine that was osmotically remediable, and the formation of a weak cell wall with a very low resistance to complex lytic enzyme preparations. The analysis of the functions downstream of the MKC1 gene should contribute to understanding of the connection of growth and morphogenesis in pathogenic fungi.

scholarly journals Involvement of a Magnaporthe grisea Serine/Threonine Kinase Gene, MgATG1, in Appressorium Turgor and Pathogenesis

2007 ◽  
Vol 6 (6) ◽  
pp. 997-1005 ◽  
Author(s):  
Xiao-Hong Liu ◽  
Jian-Ping Lu ◽  
Lei Zhang ◽  
Bo Dong ◽  
Hang Min ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Magnaporthe Grisea ◽  
Normal Development ◽  
Normal Values ◽  
Turgor Pressure ◽  
Serine Threonine Kinase ◽  
Gene Encoding ◽  
Kinase Gene ◽  
Threonine Kinase ◽  
Delayed Initiation

ABSTRACT We isolated an MgATG1 gene encoding a serine/threonine protein kinase from the rice blast fungus Magnaporthe grisea. In the ΔMgatg1 mutant, in which the MgATG1 gene had been deleted, autophagy was blocked; the mutant also showed fewer lipid droplets in its conidia, lower turgor pressure of the appressorium, and such defects in morphogenesis as delayed initiation and slower germination of conidia. As a result of lower turgor pressure of the appressorium, the ΔMgatg1 mutant lost its ability to penetrate and infect the two host plants, namely, rice and barley. However, normal values of the parameters and infective abilities were restored on reintroducing an intact copy of the MgATG1 gene into the mutant. Autophagy is thus necessary for turnover of organic matter during the formation of conidia and appressoria and for normal development and pathogenicity in M. grisea.

scholarly journals MgSlt2, a Cellular Integrity MAP Kinase Gene of the Fungal Wheat Pathogen Mycosphaerella graminicola, Is Dispensable for Penetration but Essential for Invasive Growth

2006 ◽  
Vol 19 (4) ◽  
pp. 389-398 ◽  
Author(s):  
Rahim Mehrabi ◽  
Theo van der Lee ◽  
Cees Waalwijk ◽  
Gert H. J. Kema
Keyword(s):  
Map Kinase ◽  
Expressed Sequence Tag ◽  
Mycosphaerella Graminicola ◽  
Invasive Growth ◽  
In Planta ◽  
Kinase Gene ◽  
Reading Frame ◽  
Mitogen Activated Protein ◽  
Increased Sensitivity

Among expressed sequence tag libraries of Mycosphaerella graminicola isolate IPO323, we identified a full-length cDNA clone with high homology to the mitogen-activated protein (MAP) kinase Slt2 in Saccharomyces cerevisiae. This MAP kinase consists of a 1,242-bp open reading frame, and encodes a 414-amino-acid protein. We designated this homolog MgSlt2, generated MgSlt2 knockout strains in M. graminicola isolate IPO323, and found several altered phenotypes in vitro as well as in planta. In yeast glucose broth, MgSlt2 disruptants showed a defective polarized growth in the tip cells upon aging, causing substantial local enlargements culminating in large swollen cells containing two to four nuclei. The MgSlt2 disruptants showed a significantly increased sensitivity to several fungicides, including miconazole (2×), bifonazole (>4×), imazalil (5×), and cyproconazole (10×), and were hypersensitive to glucanase. Unlike the wild type, MgSlt2 disruptants did not produce aerial mycelia and did not melanize on potato dextrose agar. Although cytological analysis in planta showed normal penetration of wheat stomata by the germ tubes of the MgSlt2 disruptants, subsequently formed hyphal filaments frequently were unable to branch out and establish invasive growth resulting in highly reduced virulence, and prevented pycnidia formation. Therefore, we conclude that MgSlt2 is a new pathogenicity factor in M. graminicola.

scholarly journals Production of Antimicrobial Defensin in Nicotiana benthamiana with a Potato Virus X Vector

2001 ◽  
Vol 14 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Hiromasa Saitoh ◽  
Akinori Kiba ◽  
Masahiro Nishihara ◽  
Saburo Yamamura ◽  
Kazumi Suzuki ◽  
...  
Keyword(s):  
Potato Virus ◽  
Nicotiana Benthamiana ◽  
Magnaporthe Grisea ◽  
Expression System ◽  
Potato Virus X ◽  
Phytopathogenic Fungi ◽  
Gene Encoding ◽  
Phytopathogenic Bacterium ◽  
Pseudomonas Cichorii ◽  
Wasabia Japonica

A recombinant plasmid, pTXS.TH, was constructed to express the gene-encoding wasabi (Wasabia japonica) defensin with the potato virus X (PVX) vector. pTXS.TH allows the expression of defensin in the host Nicotiana benthamiana, and the defensin protein WT1 can be purified from virus-infected leaves by heat treatment and affinity chromatography. WT1 exhibits strong antifungal activity toward the phytopathogenic fungi Magnaporthe grisea(50% inhibitory concentration [IC50] = 5 μg/ml) and Botrytis cinerea (IC50 = 20 μg/ml) but is weakly active against the phytopathogenic bacterium Pseudomonas cichorii. This virus-mediated expression system is a rapid and efficient method to produce and characterize antimicrobial proteins in plants. It is particularly useful for the study of proteins that are difficult to produce with other expression systems.

scholarly journals Suppression subtractive hybridization (SSH) identifies prolactin stimulation of p38 MAP kinase gene expression in Nb2 T lymphoma cells: molecular cloning of rat p38 MAP kinase

1998 ◽  
Vol 20 (1) ◽  
pp. 151-156 ◽  
Author(s):  
E Nemeth ◽  
C Bole-Feysot ◽  
LS Tashima
Keyword(s):  
Map Kinase ◽  
Suppression Subtractive Hybridization ◽  
Subtractive Hybridization ◽  
P38 Map Kinase ◽  
Kinase Gene ◽  
Nb2 Cells ◽  
Protein Map ◽  
T Lymphoma Cells ◽  
Mitogen Activated Protein ◽  
T Lymphoma

Suppression Subtractive Hybridization (SSH) has been used to compare rat Nb2 cells treated with prolactin for 1 hour with untreated cells. This new method for identifying differentially expressed genes showed that the mRNAs for at least three genes were elevated by such treatment, including a p38 mitogen activated protein (MAP) kinase. The p38 MAP kinase was cloned and the full length cDNA sequence was determined.

scholarly journals The Colletotrichum lagenarium Ste12-Like Gene CST1 Is Essential for Appressorium Penetration

2003 ◽  
Vol 16 (4) ◽  
pp. 315-325 ◽  
Author(s):  
Gento Tsuji ◽  
Satoshi Fujii ◽  
Seiji Tsuge ◽  
Tomonori Shiraishi ◽  
Yasuyuki Kubo
Keyword(s):  
Map Kinase ◽  
Lipid Droplets ◽  
Map Kinases ◽  
Cellulose Membrane ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Kinase Pathway

Colletotrichum lagenarium is the causal agent of anthracnose of cucumber. This fungus produces a darkly melanized infection structure, appressoria, to penetrate the host leaves. The C. lagenarium CMK1 gene, a homologue of the Saccharomyces cerevisiae FUS3/KSS1 mitogen-activated protein (MAP) kinase genes, was shown to regulate conidial germination, appressorium formation, and invasive growth. In S. cerevisiae, Ste12p is known to be a transcriptional factor downstream of Fus3p/Kss1p MAP kinases. To evaluate the CMK1 MAP kinase pathway, we isolated the Ste12 homologue CST1 gene from C. lagenarium and characterized. The cst1Δ strains were nonpathogenic on intact host leaves, but could form lesions when inoculated on wounded leaves. Conidia of the cst1Δ strains could germinate and form melanized appressoria on both host leaf surface and artificial cellulose membrane, but could not produce infectious hyphae from appressoria, suggesting that CST1 is essential for appressorium penetration in C. lagenarium. In addition, matured appressoria of the cst1Δ strains contained an extremely low level of lipid droplets compared with that of the wild-type strain. Lipid droplets were abundant in conidia of the cst1Δ strains, but rapidly disappeared during appressorium formation. This misscheduled lipid degradation might be related to the failure of appressorium penetration in the cst1Δ strain.

scholarly journals ras2 Controls Morphogenesis, Pheromone Response, and Pathogenicity in the Fungal Pathogen Ustilago maydis

2002 ◽  
Vol 1 (6) ◽  
pp. 954-966 ◽  
Author(s):  
Nancy Lee ◽  
James W. Kronstad
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Ustilago Maydis ◽  
Mitogen Activated Protein Kinase ◽  
Gene Encoding ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Map Kinase Pathway ◽  
Altered Cell ◽  
Kinase Pathway

ABSTRACT Ustilago maydis, a pathogen of maize, is a useful model for the analysis of mating, pathogenicity, and the morphological transition between budding and filamentous growth in fungi. As in other fungi, these processes are regulated by conserved signaling mechanisms, including the cyclic AMP (cAMP)/protein kinase A (PKA) pathway and at least one mitogen-activated protein kinase (MAP kinase) pathway. A current challenge is to identify additional factors that lie downstream of the cAMP pathway and that influence morphogenesis in U. maydis. In this study, we identified suppressor mutations that restored budding growth to a constitutively filamentous mutant with a defect in the gene encoding a catalytic subunit of PKA. Complementation of one suppressor mutation unexpectedly identified the ras2 gene, which is predicted to encode a member of the well-conserved ras family of small GTP-binding proteins. Deletion of the ras2 gene in haploid cells altered cell morphology, eliminated pathogenicity on maize seedlings, and revealed a role in the production of aerial hyphae during mating. We also used an activated ras2 allele to demonstrate that Ras2 promotes pseudohyphal growth via a MAP kinase cascade involving the MAP kinase kinase Fuz7 and the MAP kinase Ubc3. Overall, our results reveal an additional level of crosstalk between the cAMP signaling pathway and a MAP kinase pathway influenced by Ras2.

Sign in / Sign up

Export Citation Format

Share Document