Systematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae

Abstract

Fungal pathogens have evolved antioxidant defense against reactive oxygen species produced as a part of host innate immunity. Recent studies proposed peroxidases as components of antioxidant defense system. However, the role of fungal peroxidases during interaction with host plants has not been explored at the genomic level. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction placed 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. We identified significant and positive correlations among sensitivity to H2O2, peroxidase activity and fungal pathogenicity. In-depth analysis of MoPRX1 demonstrated that it is a functional ortholog of thioredoxin peroxidase in Saccharomyces cerevisiae and is required for detoxification of the oxidative burst within host cells. Transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of the peroxidase-mediated antioxidant defense system. The results from this study provide insight into the infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus.

The caterpillar fungus, Ophiocordyceps sinensis, genome provides insights into highland adaptation of fungal pathogenicity

“…A comparative analysis revealed that the retained gene in O . sinensis belongs to the Prx1 type, which was reported to be functionally conserved 27 and expressed only when the cells are exposed to high levels of H 2 O 2 generated exogenously 26 .

Figure 3Analysis of peroxidase genes and positive selection. ( A ) Comparisons of the percent and number (parentheses) of peroxidase genes among the five entomopathogenic fungi and yeast ( S .

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Reactive oxygen species metabolism and plant-fungal interactions

“…However, DAB is a slow-acting stain (8-12 h) (Thordal-Christensen et al, 1997). Another method used for H 2 O 2 detection during plant-pathogen interactions is the fluorescent dye 2,7-dichlorodihydrofluorescein diacetate (H 2 DCDA) (Huang et al, 2011;Mir et al, 2015). H 2 DCDA is membrane permeable and fluoresces when oxidized but can leak over time or be easily saturated, thus skewing results (Tarpey, 2004).…”

Influence of maternal obesity, diet and exercise on epigenetic regulation of adipocytes

“…Few studies have demonstrated that bioactive nutrients regulate adipocyte metabolism and differentiation. Fisetin, a flavonoid found in many fruits and vegetables, inhibits PPARγ acetylation in vitro (in 3T3-L1 cells) via Sirt1, while inhibition of Sirt1 activity induces PPARγ acetylation and thus contributes to increased lipid accumulation and adipocyte differentiation (Mir et al, 2015). Another phenolic compound (including chlorogenic acid, phloridzin, quercetin, catechin, epicatechin, procyanidin, and rutin), found at high concentrations in fruits such as apples, regulates adipogenesis by differentially regulating DNA methylation.…”