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

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dc.contributor.advisor이용환-
dc.contributor.author알베리-
dc.date.accessioned2017-07-13T08:23:39Z-
dc.date.available2017-07-13T08:23:39Z-
dc.date.issued2015-08-
dc.identifier.other000000067157-
dc.identifier.urihttps://hdl.handle.net/10371/119506-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 농생명공학부(식물미생물학전공), 2015. 8. 이용환.-
dc.description.abstractPlants respond to microbial attack by the rapid generation of reactive oxygen species (ROS) as part of innate immunity. Fungal pathogens have evolved effective anti-oxidant defense system as countermeasure. Recent studies proposed peroxidases as components of antioxidant defense system. However, significance of role of fungal peroxidases during interaction with host plants has not been addressed at genomic level to date. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction among 6 fungal species placed Magnaporthe oryzae 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2 where 23 genes were up-regulated during plant infection, and 15 genes were responsive to in vitro H2O2. Among them, seven genes (MoAPX1, MoAPX2, MoCCP1, MoHPX1, MoLDS1, TPX1, and MoPRX1) were selected from clades that do not contain previously characterized genes for functional analysis except TPX1. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. Importantly, we found significant positive correlation 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 required for detoxification of oxidative burst within host cells. Furthermore, transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of peroxidase-mediated anti-oxidation defense system. Taken together, this work provides overview and insights into infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus.-
dc.description.tableofcontentsINTRODUCTION 1
MATERIALS AND METHODS 5
I. Identification of peroxidase genes 5
II. Fungal strains and culture conditions 5
III. Analysis of transcript levels 6
IV. Targeted deletion of seven peroxidase genes and ΔMopxr1 complementation in M. oryzae 7
V. Nucleic acid manipulation and Southern blotting 9
VI. In vitro growth assays, infectious growth monitoring, and pathogenicity assays 9
VII. Staining of H2O2 accumulation in host cells 11
VIII. Yeast strain and complementation assays 12
IX. Measurement of extracellular peroxidase and laccase activity 13
X. Cellular localization of MoPRX1::GFP 13
XI. Computational analysis 14
RESULTS 26
I. Phylogenetic analysis of peroxidase genes in M. oryzae 26
II. Expression profiling of 27 M. oryzae peroxidase genes during fungal development and under oxidative stress 41
III. Genetic analysis of peroxidase genes and fungal pathogenicity 43
IV. Peroxidase activity, sensitivity to H2O2, and pathogenicity 46
V. MoPRX1 as a conserved peroxidase 51
VI. Roles of MoPRX1 during early phase of host infection 54
VII. Extracellular enzyme activity and transcription of other peroxidase genes can be perturbed by deletion of MoPRX1 61
DISCUSSION 65
LITERATURE CITED 72
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dc.formatapplication/pdf-
dc.format.extent3527202 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectMagnaporthe oryzae-
dc.subjectperoxidase-
dc.subjectPeroxiredoxins-
dc.subjectevolutionary conserved gene-
dc.subjectROS detoxification-
dc.subjectfungal development and pathogenicity-
dc.subjectplant-microbe interaction-
dc.subject.ddc630-
dc.titleSystematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pagesvi, 84-
dc.contributor.affiliation농업생명과학대학 농생명공학부-
dc.date.awarded2015-08-
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