Limits...
Two phosphodiesterase genes, PDEL and PDEH, regulate development and pathogenicity by modulating intracellular cyclic AMP levels in Magnaporthe oryzae.

Zhang H, Liu K, Zhang X, Tang W, Wang J, Guo M, Zhao Q, Zheng X, Wang P, Zhang Z - PLoS ONE (2011)

Bottom Line: As a second messenger, cAMP is important in the activation of downstream effector molecules.This is in contrast to PdeH whose mutation resulted in major defects in conidial morphology, cell wall integrity, and surface hydrophobicity, as well as a significant reduction in pathogenicity.Moreover, microarray data revealed new insights into the underlying cAMP regulatory mechanisms that may help to identify potential pathogenicity factors for the development of new disease management strategies.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China.

ABSTRACT
Cyclic AMP (cAMP) signaling plays an important role in regulating multiple cellular responses, such as growth, morphogenesis, and/or pathogenicity of eukaryotic organisms such as fungi. As a second messenger, cAMP is important in the activation of downstream effector molecules. The balance of intracellular cAMP levels depends on biosynthesis by adenylyl cyclases (ACs) and hydrolysis by cAMP phosphodiesterases (PDEases). The rice blast fungus Magnaporthe oryzae contains a high-affinity (PdeH/Pde2) and a low-affinity (PdeL/Pde1) PDEases, and a previous study showed that PdeH has a major role in asexual differentiation and pathogenicity. Here, we show that PdeL is required for asexual development and conidial morphology, and it also plays a minor role in regulating cAMP signaling. This is in contrast to PdeH whose mutation resulted in major defects in conidial morphology, cell wall integrity, and surface hydrophobicity, as well as a significant reduction in pathogenicity. Consistent with both PdeH and PdeL functioning in cAMP signaling, disruption of PDEH only partially rescued the mutant phenotype of ΔmagB and Δpka1. Further studies suggest that PdeH might function through a feedback mechanism to regulate the expression of pathogenicity factor Mpg1 during surface hydrophobicity and pathogenic development. Moreover, microarray data revealed new insights into the underlying cAMP regulatory mechanisms that may help to identify potential pathogenicity factors for the development of new disease management strategies.

Show MeSH

Related in: MedlinePlus

The ΔpdeL and ΔpdeH mutants have defects in conidial morphology and hyphal branching.(A) Conidia of the wild type and mutants were observed under an epi-fluorescence microscope. Conidia were stained with 1 µg/ml Calcofluor white (CFW) for 5 min in dark. (B) Conidial size of the wild type and mutants. Values are the mean ±SD from 100 conidia for each strain, which were measured using a microscope ruler. Length is the distance from the base to apex of conidia. And width is the size of the longest septum. (C) Branching patterns of mycelia on complete media slides at day 2 after incubation. Frequent branching occurs at the terminal mycelia of ΔpdeH and ΔpdeHΔpdeL double mutants. Calcofluor staining of mycelia is used to show the distance of septa.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3046207&req=5

pone-0017241-g001: The ΔpdeL and ΔpdeH mutants have defects in conidial morphology and hyphal branching.(A) Conidia of the wild type and mutants were observed under an epi-fluorescence microscope. Conidia were stained with 1 µg/ml Calcofluor white (CFW) for 5 min in dark. (B) Conidial size of the wild type and mutants. Values are the mean ±SD from 100 conidia for each strain, which were measured using a microscope ruler. Length is the distance from the base to apex of conidia. And width is the size of the longest septum. (C) Branching patterns of mycelia on complete media slides at day 2 after incubation. Frequent branching occurs at the terminal mycelia of ΔpdeH and ΔpdeHΔpdeL double mutants. Calcofluor staining of mycelia is used to show the distance of septa.

Mentions: To further explore the role of PdeL in conidiation, conidia of the ΔpdeL mutant was examined, along with and the ΔpdeH mutant and other control strains. Surprisingly, both ΔpdeL and pdeH mutants produced elongated and thinner conidia, which were uniform and readily detected under the microscope (Figure 1A). The conidia of the mutants were, on average, longer by ∼7 µm and thinner by ∼4 µm than those of the controls (Figure 1B). Frequent branching and curly tips were also observed at the terminal hyphae of the ΔpdeH deletion mutant. However, Calcofluor white (CFW) staining of mycelial cell walls showed that the septa were normal except for shorter intervals (Figure 1C). To determine whether PdeL and PdeH are involved in vegetative growth, the mutant and control strains were cultured on a variety of media including CM, OMA, SDC, or V8 juice agar media. No significant difference in colony morphology or growth rate was observed (Table 2). Combined, these findings suggested that PdeL and PdeH are indispensable for conidium morphology and but dispensable for mycelial growth.


Two phosphodiesterase genes, PDEL and PDEH, regulate development and pathogenicity by modulating intracellular cyclic AMP levels in Magnaporthe oryzae.

Zhang H, Liu K, Zhang X, Tang W, Wang J, Guo M, Zhao Q, Zheng X, Wang P, Zhang Z - PLoS ONE (2011)

The ΔpdeL and ΔpdeH mutants have defects in conidial morphology and hyphal branching.(A) Conidia of the wild type and mutants were observed under an epi-fluorescence microscope. Conidia were stained with 1 µg/ml Calcofluor white (CFW) for 5 min in dark. (B) Conidial size of the wild type and mutants. Values are the mean ±SD from 100 conidia for each strain, which were measured using a microscope ruler. Length is the distance from the base to apex of conidia. And width is the size of the longest septum. (C) Branching patterns of mycelia on complete media slides at day 2 after incubation. Frequent branching occurs at the terminal mycelia of ΔpdeH and ΔpdeHΔpdeL double mutants. Calcofluor staining of mycelia is used to show the distance of septa.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046207&req=5

pone-0017241-g001: The ΔpdeL and ΔpdeH mutants have defects in conidial morphology and hyphal branching.(A) Conidia of the wild type and mutants were observed under an epi-fluorescence microscope. Conidia were stained with 1 µg/ml Calcofluor white (CFW) for 5 min in dark. (B) Conidial size of the wild type and mutants. Values are the mean ±SD from 100 conidia for each strain, which were measured using a microscope ruler. Length is the distance from the base to apex of conidia. And width is the size of the longest septum. (C) Branching patterns of mycelia on complete media slides at day 2 after incubation. Frequent branching occurs at the terminal mycelia of ΔpdeH and ΔpdeHΔpdeL double mutants. Calcofluor staining of mycelia is used to show the distance of septa.
Mentions: To further explore the role of PdeL in conidiation, conidia of the ΔpdeL mutant was examined, along with and the ΔpdeH mutant and other control strains. Surprisingly, both ΔpdeL and pdeH mutants produced elongated and thinner conidia, which were uniform and readily detected under the microscope (Figure 1A). The conidia of the mutants were, on average, longer by ∼7 µm and thinner by ∼4 µm than those of the controls (Figure 1B). Frequent branching and curly tips were also observed at the terminal hyphae of the ΔpdeH deletion mutant. However, Calcofluor white (CFW) staining of mycelial cell walls showed that the septa were normal except for shorter intervals (Figure 1C). To determine whether PdeL and PdeH are involved in vegetative growth, the mutant and control strains were cultured on a variety of media including CM, OMA, SDC, or V8 juice agar media. No significant difference in colony morphology or growth rate was observed (Table 2). Combined, these findings suggested that PdeL and PdeH are indispensable for conidium morphology and but dispensable for mycelial growth.

Bottom Line: As a second messenger, cAMP is important in the activation of downstream effector molecules.This is in contrast to PdeH whose mutation resulted in major defects in conidial morphology, cell wall integrity, and surface hydrophobicity, as well as a significant reduction in pathogenicity.Moreover, microarray data revealed new insights into the underlying cAMP regulatory mechanisms that may help to identify potential pathogenicity factors for the development of new disease management strategies.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China.

ABSTRACT
Cyclic AMP (cAMP) signaling plays an important role in regulating multiple cellular responses, such as growth, morphogenesis, and/or pathogenicity of eukaryotic organisms such as fungi. As a second messenger, cAMP is important in the activation of downstream effector molecules. The balance of intracellular cAMP levels depends on biosynthesis by adenylyl cyclases (ACs) and hydrolysis by cAMP phosphodiesterases (PDEases). The rice blast fungus Magnaporthe oryzae contains a high-affinity (PdeH/Pde2) and a low-affinity (PdeL/Pde1) PDEases, and a previous study showed that PdeH has a major role in asexual differentiation and pathogenicity. Here, we show that PdeL is required for asexual development and conidial morphology, and it also plays a minor role in regulating cAMP signaling. This is in contrast to PdeH whose mutation resulted in major defects in conidial morphology, cell wall integrity, and surface hydrophobicity, as well as a significant reduction in pathogenicity. Consistent with both PdeH and PdeL functioning in cAMP signaling, disruption of PDEH only partially rescued the mutant phenotype of ΔmagB and Δpka1. Further studies suggest that PdeH might function through a feedback mechanism to regulate the expression of pathogenicity factor Mpg1 during surface hydrophobicity and pathogenic development. Moreover, microarray data revealed new insights into the underlying cAMP regulatory mechanisms that may help to identify potential pathogenicity factors for the development of new disease management strategies.

Show MeSH
Related in: MedlinePlus