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Crosstalk between SNF1 pathway and the peroxisome-mediated lipid metabolism in Magnaporthe oryzae.

Zeng XQ, Chen GQ, Liu XH, Dong B, Shi HB, Lu JP, Lin F - PLoS ONE (2014)

Bottom Line: And the upstream kinases, MoSak1 and MoTos3, play unequal roles in SNF1 activation with a clear preference to MoSak1 over MoTos3.Meanwhile, the mutant lacking both of them exhibited a severe phenotype comparable to ΔMosnf1, uncovering a cooperative relationship between MoSak1 and MoTos3.Taken together, our data indicate that the SNF1 pathway is required for fungal development and facilitates pathogenicity by its contribution to peroxisomal maintenance and lipid metabolism in M. oryzae.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Rice Biology, Biotechnology Institute, Zhejiang University, Hangzhou, China.

ABSTRACT
The SNF1/AMPK pathway has a central role in response to nutrient stress in yeast and mammals. Previous studies on SNF1 function in phytopathogenic fungi mostly focused on the catalytic subunit Snf1 and its contribution to the derepression of cell wall degrading enzymes (CWDEs). However, the MoSnf1 in Magnaporthe oryzae was reported not to be involved in CWDEs regulation. The mechanism how MoSnf1 functions as a virulence determinant remains unclear. In this report, we demonstrate that MoSnf1 retains the ability to respond to nutrient-free environment via its participation in peroxisomal maintenance and lipid metabolism. Observation of GFP-tagged peroxisomal targeting signal-1 (PTS1) revealed that the peroxisomes of ΔMosnf1 were enlarged in mycelia and tended to be degraded before conidial germination, leading to the sharp decline of peroxisomal amount during appressorial development, which might impart the mutant great retard in lipid droplets mobilization and degradation. Consequently, ΔMosnf1 exhibited inability to maintain normal appressorial cell wall porosity and turgor pressure, which are key players in epidermal infection process. Exogenous glucose could partially restore the appressorial function and virulence of ΔMosnf1. Toward a further understanding of SNF1 pathway, the β-subunit MoSip2, γ-subunit MoSnf4, and two putative Snf1-activating kinases, MoSak1 and MoTos3, were additionally identified and characterized. Here we show the mutants ΔMosip2 and ΔMosnf4 performed multiple disorders as ΔMosnf1 did, suggesting the complex integrity is essential for M. oryzae SNF1 kinase function. And the upstream kinases, MoSak1 and MoTos3, play unequal roles in SNF1 activation with a clear preference to MoSak1 over MoTos3. Meanwhile, the mutant lacking both of them exhibited a severe phenotype comparable to ΔMosnf1, uncovering a cooperative relationship between MoSak1 and MoTos3. Taken together, our data indicate that the SNF1 pathway is required for fungal development and facilitates pathogenicity by its contribution to peroxisomal maintenance and lipid metabolism in M. oryzae.

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Mutations in SNF1 pathway affected the utilization of non-fermentable carbons.Strains were cultured on MM plates supplemented with 1% Glucose, 1% Tween 80, 1% Olive oil, 1% Triolein, or 50 mM Sodium acetate as sole carbon source for 10 d at 25°C.
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pone-0103124-g004: Mutations in SNF1 pathway affected the utilization of non-fermentable carbons.Strains were cultured on MM plates supplemented with 1% Glucose, 1% Tween 80, 1% Olive oil, 1% Triolein, or 50 mM Sodium acetate as sole carbon source for 10 d at 25°C.

Mentions: Growth tests revealed that all the tested mutants, except ΔMotos3, exhibited severe defects in utilization of acetate, Tween 80 (the principal component is oleate), triolein (one of the typical triglycerides), and olive oil (long chain fatty acids) (Figure 4 and Table 1). The growth rate of ΔMotos3 was slightly affected except on Tween 80-contained medium (Figure 4 and Table 1). Among other mutants, the deficiency degree varied upon carbon type. Overall, the defects of ΔMosip2 and ΔMosnf4 were slightly relieved as compared to ΔMosnf1 (Figure 4 and Table 1). The mycelial growth of ΔMosak1ΔMotos3 was comparable to ΔMosak1 except on Tween 80 medium, with 88% and 75% growth reduction, respectively (Figure 4 and Table 1). These data indicate that the SNF1 pathway is of great importance to the efficient utilization of non-fermentable carbon sources in M. oryzae.


Crosstalk between SNF1 pathway and the peroxisome-mediated lipid metabolism in Magnaporthe oryzae.

Zeng XQ, Chen GQ, Liu XH, Dong B, Shi HB, Lu JP, Lin F - PLoS ONE (2014)

Mutations in SNF1 pathway affected the utilization of non-fermentable carbons.Strains were cultured on MM plates supplemented with 1% Glucose, 1% Tween 80, 1% Olive oil, 1% Triolein, or 50 mM Sodium acetate as sole carbon source for 10 d at 25°C.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4121083&req=5

pone-0103124-g004: Mutations in SNF1 pathway affected the utilization of non-fermentable carbons.Strains were cultured on MM plates supplemented with 1% Glucose, 1% Tween 80, 1% Olive oil, 1% Triolein, or 50 mM Sodium acetate as sole carbon source for 10 d at 25°C.
Mentions: Growth tests revealed that all the tested mutants, except ΔMotos3, exhibited severe defects in utilization of acetate, Tween 80 (the principal component is oleate), triolein (one of the typical triglycerides), and olive oil (long chain fatty acids) (Figure 4 and Table 1). The growth rate of ΔMotos3 was slightly affected except on Tween 80-contained medium (Figure 4 and Table 1). Among other mutants, the deficiency degree varied upon carbon type. Overall, the defects of ΔMosip2 and ΔMosnf4 were slightly relieved as compared to ΔMosnf1 (Figure 4 and Table 1). The mycelial growth of ΔMosak1ΔMotos3 was comparable to ΔMosak1 except on Tween 80 medium, with 88% and 75% growth reduction, respectively (Figure 4 and Table 1). These data indicate that the SNF1 pathway is of great importance to the efficient utilization of non-fermentable carbon sources in M. oryzae.

Bottom Line: And the upstream kinases, MoSak1 and MoTos3, play unequal roles in SNF1 activation with a clear preference to MoSak1 over MoTos3.Meanwhile, the mutant lacking both of them exhibited a severe phenotype comparable to ΔMosnf1, uncovering a cooperative relationship between MoSak1 and MoTos3.Taken together, our data indicate that the SNF1 pathway is required for fungal development and facilitates pathogenicity by its contribution to peroxisomal maintenance and lipid metabolism in M. oryzae.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Rice Biology, Biotechnology Institute, Zhejiang University, Hangzhou, China.

ABSTRACT
The SNF1/AMPK pathway has a central role in response to nutrient stress in yeast and mammals. Previous studies on SNF1 function in phytopathogenic fungi mostly focused on the catalytic subunit Snf1 and its contribution to the derepression of cell wall degrading enzymes (CWDEs). However, the MoSnf1 in Magnaporthe oryzae was reported not to be involved in CWDEs regulation. The mechanism how MoSnf1 functions as a virulence determinant remains unclear. In this report, we demonstrate that MoSnf1 retains the ability to respond to nutrient-free environment via its participation in peroxisomal maintenance and lipid metabolism. Observation of GFP-tagged peroxisomal targeting signal-1 (PTS1) revealed that the peroxisomes of ΔMosnf1 were enlarged in mycelia and tended to be degraded before conidial germination, leading to the sharp decline of peroxisomal amount during appressorial development, which might impart the mutant great retard in lipid droplets mobilization and degradation. Consequently, ΔMosnf1 exhibited inability to maintain normal appressorial cell wall porosity and turgor pressure, which are key players in epidermal infection process. Exogenous glucose could partially restore the appressorial function and virulence of ΔMosnf1. Toward a further understanding of SNF1 pathway, the β-subunit MoSip2, γ-subunit MoSnf4, and two putative Snf1-activating kinases, MoSak1 and MoTos3, were additionally identified and characterized. Here we show the mutants ΔMosip2 and ΔMosnf4 performed multiple disorders as ΔMosnf1 did, suggesting the complex integrity is essential for M. oryzae SNF1 kinase function. And the upstream kinases, MoSak1 and MoTos3, play unequal roles in SNF1 activation with a clear preference to MoSak1 over MoTos3. Meanwhile, the mutant lacking both of them exhibited a severe phenotype comparable to ΔMosnf1, uncovering a cooperative relationship between MoSak1 and MoTos3. Taken together, our data indicate that the SNF1 pathway is required for fungal development and facilitates pathogenicity by its contribution to peroxisomal maintenance and lipid metabolism in M. oryzae.

Show MeSH
Related in: MedlinePlus