Please use this identifier to cite or link to this item: https://doi.org/10.1371/journal.ppat.1000897
Title: PdeH, a high-affinity camp phosphodiesterase, is a key regulator of asexual and pathogenic differentiation in magnaporthe oryzae
Authors: Ramanujam R.
Naqvi N.I. 
Keywords: cyclic AMP
cyclic AMP phosphodiesterase
protein PdeH
protein PdeL
unclassified drug
8 bromo cyclic AMP
cyclic AMP
exonuclease
fungal protein
phosphodiesterase I
spleen exonuclease
article
conidium
controlled study
deletion mutant
developmental stage
enzyme activity
enzyme localization
fungal colonization
fungal plant disease
fungal virulence
fungus growth
Magnaporthe
Magnaporthe oryzae
nonhuman
nucleotide sequence
protein function
rice
signal transduction
vegetative growth
wild type
amino acid sequence
cell membrane
cell nucleus
cytoplasm
drug effect
enzymology
fungus hyphae
fungus spore
gene expression regulation
genetics
growth, development and aging
metabolism
microbiology
molecular genetics
mutagenesis
physiology
plant disease
rice
Magnaporthe grisea
Magnaporthe oryzae
8-Bromo Cyclic Adenosine Monophosphate
Amino Acid Sequence
Cell Membrane
Cell Nucleus
Cyclic AMP
Cytoplasm
Exonucleases
Fungal Proteins
Gene Expression Regulation, Enzymologic
Gene Expression Regulation, Fungal
Hyphae
Magnaporthe
Molecular Sequence Data
Mutagenesis
Oryza sativa
Phosphodiesterase I
Plant Diseases
Signal Transduction
Spores, Fungal
Issue Date: 2010
Citation: Ramanujam R., Naqvi N.I. (2010). PdeH, a high-affinity camp phosphodiesterase, is a key regulator of asexual and pathogenic differentiation in magnaporthe oryzae. PLoS Pathogens 6 (5) : Jan-23. ScholarBank@NUS Repository. https://doi.org/10.1371/journal.ppat.1000897
Rights: Attribution 4.0 International
Abstract: Cyclic AMP-dependent pathways mediate the communication between external stimuli and the intracellular signaling machinery, thereby influencing important aspects of cellular growth, morphogenesis and differentiation. Crucial to proper function and robustness of these signaling cascades is the strict regulation and maintenance of intracellular levels of cAMP through a fine balance between biosynthesis (by adenylate cyclases) and hydrolysis (by cAMP phosphodiesterases). We functionally characterized gene-deletion mutants of a high-affinity (PdeH) and a low-affinity (PdeL) cAMP phosphodiesterase in order to gain insights into the spatial and temporal regulation of cAMP signaling in the rice-blast fungus Magnaporthe oryzae. In contrast to the expendable PdeL function, the PdeH activity was found to be a key regulator of asexual and pathogenic development in M. oryzae. Loss of PdeH led to increased accumulation of intracellular cAMP during vegetative and infectious growth. Furthermore, the pdeHD showed enhanced conidiation (2-3 fold), precocious appressorial development, loss of surface dependency during pathogenesis, and highly reduced in planta growth and host colonization. A pdeHD pdeLD mutant showed reduced conidiation, exhibited dramatically increased (,10 fold) cAMP levels relative to the wild type, and was completely defective in virulence. Exogenous addition of 8-Br-cAMP to the wild type simulated the pdeHD defects in conidiation as well as in planta growth and development. While a fully functional GFP-PdeH was cytosolic but associated dynamically with the plasma membrane and vesicular compartments, the GFP-PdeL localized predominantly to the nucleus. Based on data from cAMP measurements and Real-Time RTPCR, we uncover a PdeH-dependent biphasic regulation of cAMP levels during early and late stages of appressorial development in M. oryzae. We propose that PdeHmediated sustenance and dynamic regulation of cAMP signaling during M. oryzae development is crucial for successful establishment and spread of the blast disease in rice. © 2010 Ramanujam, Naqvi.
Source Title: PLoS Pathogens
URI: https://scholarbank.nus.edu.sg/handle/10635/161664
ISSN: 15537366
DOI: 10.1371/journal.ppat.1000897
Rights: Attribution 4.0 International
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