Mini-Review : Population Structure and Race Variation of the Rice Blast Fungus

Seogchan Kang,Yong-Hwan Lee 한국식물병리학회 2000 Plant Pathology Journal Vol.16 No.1

Expression Patterns of Transposable Elements in Magnaporthe oryzae under Diverse Developmental and Environmental Conditions

Hyunjung Chung,Seogchan Kang,Yong-Hwan Lee,Sook-Young Park 한국식물병리학회 2020 식물병연구 Vol.26 No.1

The genome of the rice blast fungus Magnaporthe oryzae contains several types of transposable elements (TEs), and some TEs cause genetic variation that allows M. oryzae to evade host detection. We studied how five abundant TEs in rice pathogens, Pot3, Pot2, MAGGY, Line-like element (MGL) and Mg-SINE, are expressed under diverse conditions related to growth, development, and stress. Expression of Pot3 and Pot2 was ac- tivated in germinated conidia and mycelia treated with tricyclazole. Retrotransposon MAGGY was highly expressed in appressoria and tricyclazole-treated mycelia. MAGGY and Pot2 were also activated during the early and late stages of perithecia development. MGL was up-regulated in conidia and during conidial ger- mination but not during appressorium formation. No noticeable expression of Mg-SINE was observed under most conditions. Our results should help investigate if and how condition-specific expressions of some TEs contribute to the biology and evolution of M. oryzae.

Optimization of Agrobacterium tumefaciens-Mediated Transformation of Xylaria grammica EL000614, an Endolichenic Fungus Producing Grammicin

( Min-hye Jeong ),( Jung A. Kim ),( Seogchan Kang ),( Eu Ddeum Choi ),( Youngmin Kim ),( Yerim Lee ),( Mi Jin Jeon ),( Nan Hee Yu ),( Ae Ran Park ),( Jin-cheol Kim ),( Soonok Kim ),( Sook-young Park ) 한국균학회 2021 Mycobiology Vol.49 No.5

An endolichenic fungus Xylaria grammica EL000614 produces grammicin, a potent nematicidal pyrone derivative that can serve as a new control option for root-knot nematodes. We optimized an Agrobacterium tumefaciens-mediated transformation (ATMT) protocol for X. grammica to support genetic studies. Transformants were successfully generated after co-cultivation of homogenized young mycelia of X. grammica with A. tumefaciens strain AGL-1 carrying a binary vector that contains the bacterial hygromycin B phosphotransferase (hph) gene and the eGFP gene in T-DNA. The resulting transformants were mitotically stable, and PCR analysis showed the integratin of both genes in the genome of transformants. Expression of eGFP was confirmed via fluorescence microscopy. Southern analysis showed that 131 (78.9%) out of 166 transformants contained a single T-DNA insertion. Crucial factors for producing predominantly single T-DNA transformants include 48 h of co-cultivation, pretreatment of A. tumefaciens cells with acetosyringone before co-cultivation, and using freshly prepared mycelia. The established ATMT protocol offers an efficient tool for random insertional mutagenesis and gene transfer in studying the biology and ecology of X. grammica.

Roles of Forkhead-box Transcription Factors in Controlling Development, Pathogenicity, and Stress Response in Magnaporthe oryzae

Park, Jaejin,Kong, Sunghyung,Kim, Seryun,Kang, Seogchan,Lee, Yong-Hwan The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.2

Although multiple transcription factors (TFs) have been characterized via mutagenesis to understand their roles in controlling pathogenicity and infection-related development in Magnaporthe oryzae, the causal agent of rice blast, if and how forkhead-box (FOX) TFs contribute to these processes remain to be characterized. Four putative FOX TF genes were identified in the genome of M. oryzae, and phylogenetic analysis suggested that two of them (MoFKH1 and MoHCM1) correspond to Ascomycota-specific members of the FOX TF family while the others (MoFOX1 and MoFOX2) are Pezizomycotina-specific members. Deletion of MoFKH1 (${\Delta}Mofkh1$) resulted in reduced mycelial growth and conidial germination, abnormal septation and stress response, and reduced virulence. Similarly, ${\Delta}Mohcm1$ exhibited reduced mycelial growth and conidial germination. Conidia of ${\Delta}Mofkh1$ and ${\Delta}Mohcm1$ were more sensitive to one or both of the cell cycle inhibitors hydroxyurea and benomyl, suggesting their role in cell cycle control. On the other hand, loss of MoFOX1 (${\Delta}Mofox1$) did not show any noticeable changes in development, pathogenicity, and stress response. Deletion of MoFOX2 was not successful even after repeated attempts. Taken together, these results suggested that MoFKH1 and MoHCM1 are important in fungal development and that MoFKH1 is further implicated in pathogenicity and stress response in M. oryzae.

The ER chaperone LHS1 is involved in asexual development and rice infection by the blast fungus Magnaporthe oryzae.

Yi, Mihwa,Chi, Myoung-Hwan,Khang, Chang Hyun,Park, Sook-Young,Kang, Seogchan,Valent, Barbara,Lee, Yong-Hwan American Society of Plant Physiologists 2009 The Plant cell Vol.21 No.2

<P>In planta secretion of fungal pathogen proteins, including effectors destined for the plant cell cytoplasm, is critical for disease progression. However, little is known about the endoplasmic reticulum (ER) secretion mechanisms used by these pathogens. To determine if normal ER function is crucial for fungal pathogenicity, Magnaporthe oryzae genes encoding proteins homologous to yeast Lhs1p and Kar2p, members of the heat shock protein 70 family in Saccharomyces cerevisiae, were cloned and characterized. Like their yeast counterparts, both LHS1 and KAR2 proteins localized in the ER and functioned in an unfolded protein response (UPR) similar to the yeast UPR. Mutants produced by disruption of LHS1 were viable but showed a defect in the translocation of proteins across the ER membrane and reduced activities of extracellular enzymes. The Deltalhs1 mutant was severely impaired not only in conidiation, but also in both penetration and biotrophic invasion in susceptible rice (Oryza sativa) plants. This mutant also had defects in the induction of the Pi-ta resistance gene-mediated hypersensitive response and in the accumulation of fluorescently-labeled secreted effector proteins in biotrophic interfacial complexes. Our results suggest that proper processing of secreted proteins, including effectors, by chaperones in the ER is requisite for successful disease development and for determining host-pathogen compatibility via the gene-for-gene interaction.</P>

CFGP 2.0: a versatile web-based platform for supporting comparative and evolutionary genomics of fungi and Oomycetes

Choi, Jaeyoung,Cheong, Kyeongchae,Jung, Kyongyong,Jeon, Jongbum,Lee, Gir-Won,Kang, Seogchan,Kim, Sangsoo,Lee, Yin-Won,Lee, Yong-Hwan Oxford University Press 2013 Nucleic acids research Vol.41 No.d1

<P>In 2007, Comparative Fungal Genomics Platform (CFGP; http://cfgp.snu.ac.kr/) was publicly open with 65 genomes corresponding to 58 fungal and Oomycete species. The CFGP provided six bioinformatics tools, including a novel tool entitled BLASTMatrix that enables search homologous genes to queries in multiple species simultaneously. CFGP also introduced Favorite, a personalized virtual space for data storage and analysis with these six tools. Since 2007, CFGP has grown to archive 283 genomes corresponding to 152 fungal and Oomycete species as well as 201 genomes that correspond to seven bacteria, 39 plants and 105 animals. In addition, the number of tools in Favorite increased to 27. The Taxonomy Browser of CFGP 2.0 allows users to interactively navigate through a large number of genomes according to their taxonomic positions. The user interface of BLASTMatrix was also improved to facilitate subsequent analyses of retrieved data. A newly developed genome browser, Seoul National University Genome Browser (SNUGB), was integrated into CFGP 2.0 to support graphical presentation of diverse genomic contexts. Based on the standardized genome warehouse of CFGP 2.0, several systematic platforms designed to support studies on selected gene families have been developed. Most of them are connected through Favorite to allow of sharing data across the platforms.</P>

Rice blast fungus (Magnaporthe oryzae) infects Arabidopsis via a mechanism distinct from that required for the infection of rice.

Park, Ju-Young,Jin, Jianming,Lee, Yin-Won,Kang, Seogchan,Lee, Yong-Hwan American Society of Plant Physiologists 2009 Plant Physiology Vol.149 No.1

<P>Magnaporthe oryzae is a hemibiotrophic fungal pathogen that causes rice (Oryza sativa) blast. Although M. oryzae as a whole infects a wide variety of monocotyledonous hosts, no dicotyledonous plant has been reported as a host. We found that two rice pathogenic strains of M. oryzae, KJ201 and 70-15, interacted differentially with 16 ecotypes of Arabidopsis (Arabidopsis thaliana). Strain KJ201 infected all ecotypes with varying degrees of virulence, whereas strain 70-15 caused no symptoms in certain ecotypes. In highly susceptible ecotypes, small chlorotic lesions appeared on infected leaves within 3 d after inoculation and subsequently expanded across the affected leaves. The fungus produced spores in susceptible ecotypes but not in resistant ecotypes. Fungal cultures recovered from necrotic lesions caused the same symptoms in healthy plants, satisfying Koch's postulates. Histochemical analyses showed that infection by the fungus caused an accumulation of reactive oxygen species and eventual cell death. Similar to the infection process in rice, the fungus differentiated to form appressorium and directly penetrated the leaf surface in Arabidopsis. However, the pathogenic mechanism in Arabidopsis appears distinct from that in rice; three fungal genes essential for pathogenicity in rice played only limited roles in causing disease symptoms in Arabidopsis, and the fungus seems to colonize Arabidopsis as a necrotroph through the secretion of phytotoxic compounds, including 9,12-octadecadienoic acid. Expression of PR-1 and PDF1.2 was induced in response to infection by the fungus, suggesting the activation of salicylic acid- and jasmonic acid/ethylene-dependent signaling pathways. However, the roles of these signaling pathways in defense against M. oryzae remain unclear. In combination with the wealth of genetic and genomic resources available for M. oryzae, this newly established pathosystem allows comparison of the molecular and cellular mechanisms underlying pathogenesis and host defense in two well-studied model plants.</P>

Functional characterization and manipulation of the apicidin biosynthetic pathway in <i>Fusarium semitectum</i>

Jin, Jian-Ming,Lee, Seunghoon,Lee, Jungkwan,Baek, Seung-Ryul,Kim, Jin-Cheol,Yun, Sung-Hwan,Park, Sook-Young,Kang, Seogchan,Lee, Yin-Won Blackwell Publishing Ltd 2010 Molecular microbiology Vol.76 No.2

<P>Summary</P><P>Apicidin is a cyclic tetrapeptide produced by certain isolates of <I>Fusarium semitectum</I> and has been shown to inhibit Apicomplexan histone deacetylase. An apicidin-producing strain (KCTC16676) of the filamentous fungus was mutated using an <I>Agrobacterium tumefaciens</I>-mediated transformation, resulting in 24 apicidin-deficient mutants. Three of the mutants had a T-DNA insertion in a gene that encodes a non-ribosomal peptide synthetase (NRPS). Results of sequence, expression, and gene deletion analyses defined an apicidin biosynthetic gene cluster, and the NRPS gene was named as apicidin synthetase gene 1 (<I>APS1</I>). A 63 kb region surrounding <I>APS1</I> was sequenced and analysis revealed the presence of 19 genes. All of the genes including <I>APS1</I> were individually deleted to determine their roles in apicidin biosynthesis. Chemical analyses of the mutant strains showed that eight genes are required for apicidin production and were used to propose an apicidin biosynthetic pathway. The apicidin analogues apicidin E, apicidin D<SUB>2</SUB> and apicidin B were identified from chemical analysis of the mutants. The cluster gene <I>APS2</I>, a putative transcription factor, was shown to regulate expression of the genes in the cluster and overexpression of <I>APS2</I> increased apicidin production. This study establishes the apicidin biosynthetic pathway and provides new opportunities to improve the production of apicidin and produce new analogues.</P>

FTFD: an informatics pipeline supporting phylogenomic analysis of fungal transcription factors.

Park, Jongsun,Park, Jaejin,Jang, Suwang,Kim, Seryun,Kong, Sunghyung,Choi, Jaeyoung,Ahn, Kyohun,Kim, Juhyeon,Lee, Seungmin,Kim, Sunggon,Park, Bongsoo,Jung, Kyongyong,Kim, Soonok,Kang, Seogchan,Lee, Yon Oxford University Press 2008 Bioinformatics Vol.24 No.7

<P>Genomes of more than 60 fungal species have been sequenced to date, yet there has been no systematic approach to analyze fungal transcription factors (TFs) kingdom widely. We developed a standardized pipeline for annotating TFs in fungal genomes. Resulting data have been archived in a new database termed the Fungal Transcription Factor Database (FTFD). In FTFD, 31,832 putative fungal TFs, identified from 62 fungal and 3 Oomycete species, were classified into 61 families and phylogenetically analyzed. The FTFD will serve as a community resource supporting comparative analyses of the distribution and domain structure of TFs within and across species.</P>

Cyber infrastructure for <i>Fusarium</i> : three integrated platforms supporting strain identification, phylogenetics, comparative genomics and knowledge sharing

Park, Bongsoo,Park, Jongsun,Cheong, Kyeong-Chae,Choi, Jaeyoung,Jung, Kyongyong,Kim, Donghan,Lee, Yong-Hwan,Ward, Todd J.,O'Donnell, Kerry,Geiser, David M.,Kang, Seogchan Oxford University Press 2011 Nucleic acids research Vol.39 No.1

<P>The fungal genus <I>Fusarium</I> includes many plant and/or animal pathogenic species and produces diverse toxins. Although accurate species identification is critical for managing such threats, it is difficult to identify <I>Fusarium</I> morphologically. Fortunately, extensive molecular phylogenetic studies, founded on well-preserved culture collections, have established a robust foundation for <I>Fusarium</I> classification. Genomes of four <I>Fusarium</I> species have been published with more being currently sequenced. The Cyber infrastructure for <I>Fusarium</I> (CiF; http://www.fusariumdb.org/) was built to support archiving and utilization of rapidly increasing data and knowledge and consists of Fusarium-ID, Fusarium Comparative Genomics Platform (FCGP) and Fusarium Community Platform (FCP). The Fusarium-ID archives phylogenetic marker sequences from most known species along with information associated with characterized isolates and supports strain identification and phylogenetic analyses. The FCGP currently archives five genomes from four species. Besides supporting genome browsing and analysis, the FCGP presents computed characteristics of multiple gene families and functional groups. The Cart/Favorite function allows users to collect sequences from Fusarium-ID and the FCGP and analyze them later using multiple tools without requiring repeated copying-and-pasting of sequences. The FCP is designed to serve as an online community forum for sharing and preserving accumulated experience and knowledge to support future research and education.</P>