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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

The deletion mutants were sensitive to H2O2.(A) Middle panels of figures show colony morphology of the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1, complemented strains ΔFoSlt2-c and ΔFoMkk2-c were incubated on MM plates supplemented with 4 mM H2O2 at 28°C for 3.5 days. Right panels of figures show inhibition of the radiated growth of the indicated strains grown on the MM plates with the same order as the middle figures. (B) Quantitative real-time PCR analysis of peroxidase synthase genes in the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1. The four peroxidase synthase genes are FOIG_08821, FOIG_07465, FOIG_04532 and FOIG_09161. Error bars indicate the standard error from three replicates.
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pone.0122634.g004: The deletion mutants were sensitive to H2O2.(A) Middle panels of figures show colony morphology of the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1, complemented strains ΔFoSlt2-c and ΔFoMkk2-c were incubated on MM plates supplemented with 4 mM H2O2 at 28°C for 3.5 days. Right panels of figures show inhibition of the radiated growth of the indicated strains grown on the MM plates with the same order as the middle figures. (B) Quantitative real-time PCR analysis of peroxidase synthase genes in the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1. The four peroxidase synthase genes are FOIG_08821, FOIG_07465, FOIG_04532 and FOIG_09161. Error bars indicate the standard error from three replicates.

Mentions: The sensitivities of WT, three MAP kinase mutants and the complemented strains ΔFoSlt2-c and ΔFoMkk2-c to oxidative stress were tested. The results showed that three mutants were more sensitive to 4 mM H2O2 than WT and the corresponding complemented strains (Fig 4A). Moreover, quantitative real-time PCR analysis showed that except for FOIG_09161 in mutant ΔFoBck1, the four peroxidase synthase genes were down-regulated in the three mutants compared with WT (Fig 4B). Collectively, these findings indicate that the MAP kinases may play a vital role in regulation of the degradation of extracellular reactive oxygen species (ROS). Generation of ROS is a well-known hallmark event in host plant defense mechanisms [18].


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)

The deletion mutants were sensitive to H2O2.(A) Middle panels of figures show colony morphology of the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1, complemented strains ΔFoSlt2-c and ΔFoMkk2-c were incubated on MM plates supplemented with 4 mM H2O2 at 28°C for 3.5 days. Right panels of figures show inhibition of the radiated growth of the indicated strains grown on the MM plates with the same order as the middle figures. (B) Quantitative real-time PCR analysis of peroxidase synthase genes in the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1. The four peroxidase synthase genes are FOIG_08821, FOIG_07465, FOIG_04532 and FOIG_09161. 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.g004: The deletion mutants were sensitive to H2O2.(A) Middle panels of figures show colony morphology of the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1, complemented strains ΔFoSlt2-c and ΔFoMkk2-c were incubated on MM plates supplemented with 4 mM H2O2 at 28°C for 3.5 days. Right panels of figures show inhibition of the radiated growth of the indicated strains grown on the MM plates with the same order as the middle figures. (B) Quantitative real-time PCR analysis of peroxidase synthase genes in the WT, mutants ΔFoSlt2, ΔFoMkk2 and ΔFoBck1. The four peroxidase synthase genes are FOIG_08821, FOIG_07465, FOIG_04532 and FOIG_09161. Error bars indicate the standard error from three replicates.
Mentions: The sensitivities of WT, three MAP kinase mutants and the complemented strains ΔFoSlt2-c and ΔFoMkk2-c to oxidative stress were tested. The results showed that three mutants were more sensitive to 4 mM H2O2 than WT and the corresponding complemented strains (Fig 4A). Moreover, quantitative real-time PCR analysis showed that except for FOIG_09161 in mutant ΔFoBck1, the four peroxidase synthase genes were down-regulated in the three mutants compared with WT (Fig 4B). Collectively, these findings indicate that the MAP kinases may play a vital role in regulation of the degradation of extracellular reactive oxygen species (ROS). Generation of ROS is a well-known hallmark event in host plant defense mechanisms [18].

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