scholarly journals Cpk2, a catalytic subunit of cyclic AMP-PKA, regulates growth and pathogenesis in rice blast

2017 ◽  
Author(s):  
Poonguzhali Selvaraj ◽  
Qing Shen ◽  
Fan Yang ◽  
Naweed I. Naqvi
Keyword(s):  
Rice Blast ◽  
Catalytic Subunit ◽  
In Planta ◽  
Gene Encoding ◽  
Double Deletion ◽  
Surface Sensing ◽  
Host Penetration ◽  
Single Deletion ◽  
Complete Failure ◽  
Germ Tubes

SummaryThe cAMP-Protein Kinase A signalling, anchored on CpkA, is necessary for appressorium development and host penetration, but indispensable for infectious growth in Magnaporthe oryzae. In this study, we identified and characterized the gene encoding the second catalytic subunit, CPK2, whose expression was found to be lower compared to CPKA at various stages of pathogenic growth in M. oryzae. Deletion of CPK2 caused no alterations in vegetative growth, conidiation, appressorium formation, or pathogenicity. Surprisingly, the cpkAΔcpk2Δ double deletion strain displayed significant reduction in growth rate and conidiation compared to the single deletion mutants. Interestingly, loss of CPKA and CPK2 resulted in morphogenetic defects in germ tubes (with curled/wavy and serpentine growth pattern) on hydrophobic surfaces, and a complete failure to produce appressoria therein, thus suggesting an important role for CPK2-mediated cAMP-PKA in surface sensing and response pathway. CPKA promoter-driven CPK2 expression partially suppressed the defects in host penetration and pathogenicity in the cpkAΔ. Such ectopic CPK2 expressing strain successfully penetrated the rice leaves, but was unable to produce proper secondary invasive hyphae, thus underscoring the importance of CpkA in growth and differentiation in planta. The Cpk2-GFP localized to the nucleus and cytoplasmic vesicles in conidia and the germ tubes. The Cpk2-GFP colocalized with CpkA-mCherry on vesicles in the cytosol, but such overlap was not evident in the nucleus. Our studies indicate that CpkA and Cpk2 share overlapping functions, but also play distinct roles during pathogenesis-associated signalling and morphogenesis in the rice blast fungus.

scholarly journals Defects in Mitochondrial and Peroxisomal β-Oxidation Influence Virulence in the Maize Pathogen Ustilago maydis

2012 ◽  
Vol 11 (8) ◽  
pp. 1055-1066 ◽  
Author(s):  
Matthias Kretschmer ◽  
Jana Klose ◽  
James W. Kronstad
Keyword(s):  
Ustilago Maydis ◽  
Short Chain Fatty Acids ◽  
Phytopathogenic Fungi ◽  
Metabolic Adaptation ◽  
In Planta ◽  
Gene Encoding ◽  
Disease Symptoms ◽  
Content Type ◽  
C Terminus ◽  
Fungal Phytopathogens

ABSTRACTAn understanding of metabolic adaptation during the colonization of plants by phytopathogenic fungi is critical for developing strategies to protect crops. Lipids are abundant in plant tissues, and fungal phytopathogens in the phylum basidiomycota possess both peroxisomal and mitochondrial β-oxidation pathways to utilize this potential carbon source. Previously, we demonstrated a role for the peroxisomal β-oxidation enzyme Mfe2 in the filamentous growth, virulence, and sporulation of the maize pathogenUstilago maydis. However,mfe2mutants still caused disease symptoms, thus prompting a more detailed investigation of β-oxidation. We now demonstrate that a defect in thehad1gene encoding hydroxyacyl coenzyme A dehydrogenase for mitochondrial β-oxidation also influences virulence, although its paralog,had2, makes only a minor contribution. Additionally, we identified a gene encoding a polypeptide with similarity to the C terminus of Mfe2 and designated it Mfe2b; this gene makes a contribution to virulence only in the background of anmfe2Δ mutant. We also show that short-chain fatty acids induce cell death inU. maydisand that a block in β-oxidation leads to toxicity, likely because of the accumulation of toxic intermediates. Overall, this study reveals that β-oxidation has a complex influence on the formation of disease symptoms byU. maydisthat includes potential metabolic contributions to proliferationin plantaand an effect on virulence-related morphogenesis.

scholarly journals Transcriptomic and Phenotypic Analyses of the Sigma B-Dependent Characteristics and the Synergism between Sigma B and Sigma L in Listeria monocytogenes EGD-e

2020 ◽  
Vol 8 (11) ◽  
pp. 1644
Author(s):  
Mirjami Mattila ◽  
Panu Somervuo ◽  
Hannu Korkeala ◽  
Roger Stephan ◽  
Taurai Tasara
Keyword(s):  
Cold Stress ◽  
Acid Stress ◽  
Cellular Functions ◽  
Phenotypic Analysis ◽  
Double Deletion ◽  
New Genes ◽  
Genome Wide ◽  
Sigma B ◽  
Single Deletion ◽  
Increased Sensitivity

Numerous gene expression and stress adaptation responses in L. monocytogenes are regulated through alternative sigma factors σB and σL. Stress response phenotypes and transcriptomes were compared between L. monocytogenes EGD-e and its ΔsigB and ΔsigBL mutants. Targeted growth phenotypic analysis revealed that the ΔsigB and ΔsigBL mutants are impaired during growth under cold and organic-acid stress conditions. Phenotypic microarrays revealed increased sensitivity in both mutants to various antimicrobial compounds. Genes de-regulated in these two mutants were identified by genome-wide transcriptome analysis during exponential growth in BHI. The ΔsigB and ΔsigBL strains repressed 198 and 254 genes, respectively, compared to the parent EGD-e strain at 3 °C, whereas 86 and 139 genes, respectively, were repressed in these mutants during growth at 37 °C. Genes repressed in these mutants are involved in various cellular functions including transcription regulation, energy metabolism and nutrient transport functions, and viral-associated processes. Exposure to cold stress induced a significant increase in σB and σL co-dependent genes of L. monocytogenes EGD-e since most (62%) of the down-regulated genes uncovered at 3 °C were detected in the ΔsigBL double-deletion mutant but not in ΔsigB or ΔsigL single-deletion mutants. Overall, the current study provides an expanded insight into σB and σL phenotypic roles and functional interactions in L. monocytogenes. Besides previously known σB- and σL-dependent genes, the transcriptomes defined in ΔsigB and ΔsigBL mutants reveal several new genes that are positively regulated by σB alone, as well as those co-regulated through σB- and σL-dependent mechanisms during L. monocytogenes growth under optimal and cold-stress temperature conditions.

scholarly journals Polyamines Are Essential for the Formation of Plague Biofilm

2006 ◽  
Vol 188 (7) ◽  
pp. 2355-2363 ◽  
Author(s):  
Chandra N. Patel ◽  
Brian W. Wortham ◽  
J. Louise Lines ◽  
Jacqueline D. Fetherston ◽  
Robert D. Perry ◽  
...  
Keyword(s):  
High Performance ◽  
Laser Scanning ◽  
Double Mutant ◽  
Arginine Decarboxylase ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Crystal Violet Staining ◽  
Liquid Chromatography Mass Spectrometry ◽  
Double Deletion ◽  
Single Deletion

ABSTRACT We provide the first evidence for a link between polyamines and biofilm levels in Yersinia pestis, the causative agent of plague. Polyamine-deficient mutants of Y. pestis were generated with a single deletion in speA or speC and a double deletion mutant. The genes speA and speC code for the biosynthetic enzymes arginine decarboxylase and ornithine decarboxylase, respectively. The level of the polyamine putrescine compared to the parental speA + speC + strain (KIM6+) was depleted progressively, with the highest levels found in the Y. pestis ΔspeC mutant (55% reduction), followed by the ΔspeA mutant (95% reduction) and the ΔspeA ΔspeC mutant (>99% reduction). Spermidine, on the other hand, remained constant in the single mutants but was undetected in the double mutant. The growth rates of mutants with single deletions were not altered, while the ΔspeA ΔspeC mutant grew at 65% of the exponential growth rate of the speA + speC + strain. Biofilm levels were assayed by three independent measures: Congo red binding, crystal violet staining, and confocal laser scanning microscopy. The level of biofilm correlated to the level of putrescine as measured by high-performance liquid chromatography-mass spectrometry and as observed in a chemical complementation curve. Complementation of the ΔspeA ΔspeC mutant with speA showed nearly full recovery of biofilm to levels observed in the speA + speC + strain. Chemical complementation of the double mutant and recovery of the biofilm defect were only observed with the polyamine putrescine.

scholarly journals Plant immunity triggered by engineered in vivo release of oligogalacturonides, damage-associated molecular patterns

2015 ◽  
Vol 112 (17) ◽  
pp. 5533-5538 ◽  
Author(s):  
Manuel Benedetti ◽  
Daniela Pontiggia ◽  
Sara Raggi ◽  
Zhenyu Cheng ◽  
Flavio Scaloni ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Inducible Promoter ◽  
Spectrometric Analysis ◽  
In Planta ◽  
Gene Encoding ◽  
Polygalacturonase Inhibiting Protein ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Oligogalacturonides (OGs) are fragments of pectin that activate plant innate immunity by functioning as damage-associated molecular patterns (DAMPs). We set out to test the hypothesis that OGs are generated in planta by partial inhibition of pathogen-encoded polygalacturonases (PGs). A gene encoding a fungal PG was fused with a gene encoding a plant polygalacturonase-inhibiting protein (PGIP) and expressed in transgenic Arabidopsis plants. We show that expression of the PGIP–PG chimera results in the in vivo production of OGs that can be detected by mass spectrometric analysis. Transgenic plants expressing the chimera under control of a pathogen-inducible promoter are more resistant to the phytopathogens Botrytis cinerea, Pectobacterium carotovorum, and Pseudomonas syringae. These data provide strong evidence for the hypothesis that OGs released in vivo act as a DAMP signal to trigger plant immunity and suggest that controlled release of these molecules upon infection may be a valuable tool to protect plants against infectious diseases. On the other hand, elevated levels of expression of the chimera cause the accumulation of salicylic acid, reduced growth, and eventually lead to plant death, consistent with the current notion that trade-off occurs between growth and defense.

scholarly journals The Multifunctional β-Oxidation Enzyme Is Required for Full Symptom Development by the Biotrophic Maize Pathogen Ustilago maydis

2006 ◽  
Vol 5 (12) ◽  
pp. 2047-2061 ◽  
Author(s):  
Jana Klose ◽  
James W. Kronstad
Keyword(s):  
Fatty Acids ◽  
Ustilago Maydis ◽  
Long Chain Fatty Acids ◽  
In Planta ◽  
Gene Encoding ◽  
Metabolic Role ◽  
Fungal Phytopathogen ◽  
Long Chain ◽  
Chain Fatty Acids

ABSTRACT The transition from yeast-like to filamentous growth in the biotrophic fungal phytopathogen Ustilago maydis is a crucial event for pathogenesis. Previously, we showed that fatty acids induce filamentation in U. maydis and that the resulting hyphal cells resemble the infectious filaments observed in planta. To explore the potential metabolic role of lipids in the morphological transition and in pathogenic development in host tissue, we deleted the mfe2 gene encoding the multifunctional enzyme that catalyzes the second and third reactions in β-oxidation of fatty acids in peroxisomes. The growth of the strains defective in mfe2 was attenuated on long-chain fatty acids and abolished on very-long-chain fatty acids. The mfe2 gene was not generally required for the production of filaments during mating in vitro, but loss of the gene blocked extensive proliferation of fungal filaments in planta. Consistent with this observation, mfe2 mutants exhibited significantly reduced virulence in that only 27% of infected seedlings produced tumors compared to 88% tumor production upon infection by wild-type strains. Similarly, a defect in virulence was observed in developing ears upon infection of mature maize plants. Specifically, the absence of the mfe2 gene delayed the development of teliospores within mature tumor tissue. Overall, these results indicate that the ability to utilize host lipids contributes to the pathogenic development of U. maydis.

An Anti-hydrotactic Response and Solid Surface Recognition of Germ Tubes of the Rice Blast Fungus,Magnaporthe gvisea

1997 ◽  
Vol 61 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
Jin-zhong Xiao ◽  
Tadakazu Watanabe ◽  
Shigeko Sekido ◽  
Woo-Bong Choi ◽  
Takashi Kamakura ◽  
...  
Keyword(s):  
Solid Surface ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Surface Recognition ◽  
Blast Fungus ◽  
Germ Tubes

scholarly journals Characterization of TUP1, a mediator of glucose repression in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (12) ◽  
pp. 6500-6511 ◽  
Author(s):  
F E Williams ◽  
R J Trumbly
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Insertional Mutagenesis ◽  
Glucose Repression ◽  
Coding Region ◽  
Gene Encoding ◽  
Reading Frame ◽  
C Terminus ◽  
Single Deletion ◽  
Rna Mapping ◽  
Mutant Phenotypes

The TUP1 and CYC8 (= SSN6) genes of Saccharomyces cerevisiae play a major role in glucose repression. Mutations in either TUP1 or CYC8 eliminate or reduce glucose repression of many repressible genes and induce other phenotypes, including flocculence, failure to sporulate, and sterility of MAT alpha cells. The TUP1 gene was isolated in a screen for genes that regulate mating type (V.L. MacKay, Methods Enzymol. 101:325-343, 1983). We found that a 3.5-kb restriction fragment was sufficient for complete complementation of tup1-100. The gene was further localized by insertional mutagenesis and RNA mapping. Sequence analysis of 2.9 kb of DNA including TUP1 revealed only one long open reading frame which predicts a protein of molecular weight 78,221. The predicted protein is rich in serine, threonine, and glutamine. In the carboxyl region there are six repeats of a pattern of about 43 amino acids. This same pattern of conserved residues is seen in the beta subunit of transducin and the yeast CDC4 gene product. Insertion and deletion mutants are viable, with the same range of phenotypes as for point mutants. Deletions of the 3' end of the coding region produced the same mutant phenotypes as did total deletions, suggesting that the C terminus is critical for TUP1 function. Strains with deletions in both the CYC8 and TUP1 genes are viable, with phenotypes similar to those of strains with a single deletion. A deletion mutation of TUP1 was able to suppress the snf1 mutation block on expression of the SUC2 gene encoding invertase.

Sign in / Sign up

Export Citation Format

Share Document