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Mitogen-activated protein kinases are associated with the regulation of physiological traits and virulence in Fusarium oxysporum f. sp. cubense.

Ding Z, Li M, Sun F, Xi P, Sun L, Zhang L, Jiang Z - PLoS ONE (2015)

Bottom Line: Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid.Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2.Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China; Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China.

ABSTRACT
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing devastating vascular wilt disease of banana plants and has become a great concern threatening banana production worldwide. However, little information is known about the molecular mechanisms that govern the expression of virulence determinants of this important fungal pathogen. In this study, we showed that mutation of three mitogen-activated protein (MAP) kinase genes, designated as FoSlt2, FoMkk2 and FoBck1, respectively, led to substantial attenuation in fungal virulence on banana plants. Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid. Biochemical analysis further confirmed the essential role of MAP kinases in modulating the production of fusaric acid, which was a crucial phytotoxin in accelerating development of Fusarium wilt symptoms in banana plants. Additionally, we found that the MAP kinase FoSlt2 was required for siderophore biosynthesis under iron-depletion conditions. Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2. Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.

No MeSH data available.


Related in: MedlinePlus

Determination of siderophore biosynthesis in mutant ΔFoSlt2 during iron-poor conditions.(A) The siderophore biosynthetic gene sidA was upregulated in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT using quantitative real-time PCR. (B) CAS assay showed increased level of secreted siderophores in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT. The indicated strains were incubated for 5 days and the supernatants were analyzed for siderophore content. Error bars indicate the standard error from three replicates.
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pone.0122634.g005: Determination of siderophore biosynthesis in mutant ΔFoSlt2 during iron-poor conditions.(A) The siderophore biosynthetic gene sidA was upregulated in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT using quantitative real-time PCR. (B) CAS assay showed increased level of secreted siderophores in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT. The indicated strains were incubated for 5 days and the supernatants were analyzed for siderophore content. Error bars indicate the standard error from three replicates.

Mentions: FOIG_11772 encodes a predicted orthologue of the L-ornithine N (5)- monooxygenase encoded by the sidA gene of Aspergillus nidulans [19]. To test whether the expression of this siderophore biosynthetic gene is influenced by disruption of the MAP kinase genes, we grew WT and three MAP kinases mutants in iron-poor and-replete conditions. Quantitative real-time PCR analysis showed that the siderophore biosynthetic gene sidA was sharply upregulated in mutant ΔFoSlt2 (2-fold) but not in ΔFoMkk2 and ΔFoBck1 during iron-poor conditions (Fig 5A). In line with quantitative real-time PCR data, a chrome azurol S (CAS) assay detected about a 1.4-fold increase in siderophore level in mutant ΔFoSlt2 in comparison with the WT (Fig 5B). These results demonstrate that FoSlt2 is involved in the regulation of siderophore biosynthesis in FOC during iron-poor conditions.


Mitogen-activated protein kinases are associated with the regulation of physiological traits and virulence in Fusarium oxysporum f. sp. cubense.

Ding Z, Li M, Sun F, Xi P, Sun L, Zhang L, Jiang Z - PLoS ONE (2015)

Determination of siderophore biosynthesis in mutant ΔFoSlt2 during iron-poor conditions.(A) The siderophore biosynthetic gene sidA was upregulated in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT using quantitative real-time PCR. (B) CAS assay showed increased level of secreted siderophores in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT. The indicated strains were incubated for 5 days and the supernatants were analyzed for siderophore content. Error bars indicate the standard error from three replicates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4388850&req=5

pone.0122634.g005: Determination of siderophore biosynthesis in mutant ΔFoSlt2 during iron-poor conditions.(A) The siderophore biosynthetic gene sidA was upregulated in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT using quantitative real-time PCR. (B) CAS assay showed increased level of secreted siderophores in mutant ΔFoSlt2 during iron-poor conditions, normalized to WT. The indicated strains were incubated for 5 days and the supernatants were analyzed for siderophore content. Error bars indicate the standard error from three replicates.
Mentions: FOIG_11772 encodes a predicted orthologue of the L-ornithine N (5)- monooxygenase encoded by the sidA gene of Aspergillus nidulans [19]. To test whether the expression of this siderophore biosynthetic gene is influenced by disruption of the MAP kinase genes, we grew WT and three MAP kinases mutants in iron-poor and-replete conditions. Quantitative real-time PCR analysis showed that the siderophore biosynthetic gene sidA was sharply upregulated in mutant ΔFoSlt2 (2-fold) but not in ΔFoMkk2 and ΔFoBck1 during iron-poor conditions (Fig 5A). In line with quantitative real-time PCR data, a chrome azurol S (CAS) assay detected about a 1.4-fold increase in siderophore level in mutant ΔFoSlt2 in comparison with the WT (Fig 5B). These results demonstrate that FoSlt2 is involved in the regulation of siderophore biosynthesis in FOC during iron-poor conditions.

Bottom Line: Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid.Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2.Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China; Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China.

ABSTRACT
Fusarium oxysporum f. sp. cubense (FOC) is an important soil-borne fungal pathogen causing devastating vascular wilt disease of banana plants and has become a great concern threatening banana production worldwide. However, little information is known about the molecular mechanisms that govern the expression of virulence determinants of this important fungal pathogen. In this study, we showed that mutation of three mitogen-activated protein (MAP) kinase genes, designated as FoSlt2, FoMkk2 and FoBck1, respectively, led to substantial attenuation in fungal virulence on banana plants. Transcriptional analysis revealed that the MAP kinase signaling pathway plays a key role in regulation of the genes encoding production of chitin, peroxidase, beauvericin and fusaric acid. Biochemical analysis further confirmed the essential role of MAP kinases in modulating the production of fusaric acid, which was a crucial phytotoxin in accelerating development of Fusarium wilt symptoms in banana plants. Additionally, we found that the MAP kinase FoSlt2 was required for siderophore biosynthesis under iron-depletion conditions. Moreover, disruption of the MAP kinase genes resulted in abnormal hypha and increased sensitivity to Congo Red, Calcofluor White and H2O2. Taken together, these results depict the critical roles of MAP kinases in regulation of FOC physiology and virulence.

No MeSH data available.


Related in: MedlinePlus