1.Nuclear Effectors in Plant Pathogenic Fungi
Surajit De MANDAL ; Junhyun JEON
Mycobiology 2022;50(5):259-268
The nuclear import of proteins is a fundamental process in the eukaryotes including plant. It has become evident that such basic process is exploited by nuclear effectors that contain nuclear localization signal (NLS) and are secreted into host cells by fungal pathogens of plants. However, only a handful of nuclear effectors have been known and characterized to date. Here, we first summarize the types of NLSs and prediction tools available, and then delineate examples of fungal nuclear effectors and their roles in pathogenesis. Based on the knowledge on NLSs and what has been gleaned from the known nuclear effectors, we point out the gaps in our understanding of fungal nuclear effectors that need to be filled in the future researches.
2.Genomic Insights into the Rice Blast Fungus through Estimation of Gene Emergence Time in Phylogenetic Context.
Jaeyoung CHOI ; Jong Joon LEE ; Junhyun JEON
Mycobiology 2018;46(4):361-369
The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.
Base Composition
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Bias (Epidemiology)
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Child
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Child, Orphaned
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Codon
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Fungi*
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Genome
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Humans
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Magnaporthe
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Methods
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Oryza
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Reproduction, Asexual
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Virulence
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Virulence Factors
3.A Nucleolar Protein, MoRRP8 Is Required for Development and Pathogenicity in the Rice Blast Fungus
Minji KIM ; Song Hee LEE ; Junhyun JEON
Mycobiology 2023;51(5):273-280
The nucleolus is the largest, membrane-less organelle within the nucleus of eukaryotic cell that plays a critical role in rRNA transcription and assembly of ribosomes. Recently, the nucle olus has been shown to be implicated in an array of processes including the formation of sig nal recognition particles and response to cellular stress. Such diverse functions of nucleolus are mediated by nucleolar proteins. In this study, we characterized a gene coding a putative protein containing a nucleolar localization sequence (NoLS) in the rice blast fungus, Magnaporthe oryzae. Phylogenetic and domain analysis suggested that the protein is ortholo gous to Rrp8 in Saccharomyces cerevisiae. MoRRP8-GFP (translational fusion of MoRRP8 with green fluorescence protein) co-localizes with a nucleolar marker protein, MoNOP1 fused to red fluorescence protein (RFP), indicating that MoRRP8 is a nucleolar protein. Deletion of the MoRRP8 gene caused a reduction in vegetative growth and impinged largely on asexual sporulation. Although the asexual spores of ΔMorrp8 were morphologically indistinguishable from those of wild-type, they showed delay in germination and reduction in appressorium formation. Our pathogenicity assay revealed that the MoRRP8 is required for full virulence and growth within host plants. Taken together, these results suggest that nucleolar processes mediated by MoRRP8 is pivotal for fungal development and pathogenesis.
4.Functional genomics in the rice blast fungus to unravel the fungal pathogenicity.
Junhyun JEON ; Jaehyuk CHOI ; Jongsun PARK ; Yong-Hwan LEE
Journal of Zhejiang University. Science. B 2008;9(10):747-752
A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.
Agrobacterium tumefaciens
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genetics
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Databases, Genetic
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Genome, Fungal
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Genomics
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Magnaporthe
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genetics
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pathogenicity
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Mutagenesis, Insertional
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Oryza
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microbiology
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Phenotype
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Plant Diseases
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microbiology
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Transformation, Genetic
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Virulence
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genetics
5.Meteorological Conditions Related to the Onset of Idiopathic Sudden Sensorineural Hearing Loss.
Jae Hyun SEO ; Eun Ju JEON ; Yong Soo PARK ; Junhyun KIM ; Ki Hong CHANG ; Sang Won YEO
Yonsei Medical Journal 2014;55(6):1678-1682
PURPOSE: The objective of this study was to evaluate the effect of meteorological factors on the onset of idiopathic sudden sensorineural hearing loss (ISSHL). MATERIALS AND METHODS: Meteorological data from 2005 to 2011 were obtained from the web-based "Monthly Weather Reports of the Meteorological Administration" database. Patients with ISSHL who visited our hospital during this same period and presented the precise day on which hearing loss developed were included in this retrospective study. Twelve meteorological factors were analyzed between the days when ISSHL onset was observed as well as the days when ISSHL did not occur. The weather conditions occurring 1-7 days before ISSHL onset were also analyzed to assess any possible delayed effects of meteorological factors on the onset of ISSHL. RESULTS: During the study period, 607 patients were included for the study. Although mean and maximal wind velocities were higher for the days when ISSHL occurred than the days without ISSHL onset, after adjusting the value for multiple comparisons, we cannot find any significant relationship between any of meteorological factors and the onset of ISSHL. However, in analysis of time lag effect of the weather conditions, we found that there was still a significant difference in maximum wind speed on 5 days before ISSHL onset even after applying Bonferroni correction. CONCLUSION: The result of this study suggests that stronger wind speed may be related to the occurrence of ISSHL.
Adult
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Female
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Hearing Loss, Sensorineural/diagnosis/*etiology
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Hearing Loss, Sudden/diagnosis/*etiology
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Humans
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Male
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*Meteorological Concepts
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Middle Aged
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Retrospective Studies
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*Wind