Home ＞GCOE Researchers ＞Takashi TSUGE

GCOE Researchers

Takashi TSUGE

Affiliation
/Position		 Graduate School of Bioagricultural Sciences, Department of Bioengineering Sciences, Professor
Doctorate Doctor of Agriculture
Research interests Plant pathology, pathogenicity and spore formation in plant pathogenic fungi
address ttsuge＠nuagr1.agr.nagoya-u.ac.jp
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+81-52-789-4030
  Laboratory

Outline of research

Even with today’s advanced agricultural techniques, about 10% of food worldwide is lost to crop diseases every year. About 80% of crop diseases threatening a stable supply of food are due to infection by filamentous fungi (mold). By elucidating the mechanism of fungal infection in plants, our research group hopes to develop new techniques to protect plants from diseases. In particular, we are working on two types of plant pathogenic fungi, Alternaria alternata and Fusarium oxysporum.

There are seven variants in A. alternate, which cause necrotic diseases in different plants. The host range of these pathogens is determined by a secondary metabolite (host-specific toxin) that exhibits toxicity only against host plants. Our research group isolated toxin synthesis gene clusters from pathogens infecting Japanese pear, apple, citrus, and tomato. Furthermore, we demonstrated that these gene clusters are encoded by a conditionally dispensable (CD) chromosome, an extra chromosome that is not necessary for vegetative growth or spore formation. Currently, we are conducting comparative genomics on the structure and function of CD chromosomes of these pathogens.

F. oxysporum has intraspecific variants, which causes vascular wilts in about 80 different crops by directly penetrating roots and colonizing the vascular tissue. Using a gene-tagging method in a pathogen that infects melon, we identified five novel pathogenicity genes. Two of these, FOW2 and FOW3, encode transcription factors that are specifically involved in infecting host plants. Therefore, we are working to identify genes directly involving in plant infection controlled by these two factors.

F. oxysporum forms three types of asexual spores: microconidia, macroconidia, and chlamydospores; each spore type plays an important role in disease onset, either as a source of infection or as a mechanism for persistence. We are currently characterizing two transcription factors, Ren1 and FoStuA, that play central roles in spore formation; we are also studying the genes controlled by both factors, and elucidating the gene expression network involved in spore formation.

References

  1. Miyamoto Y. et al. (2008) Functional analysis of a multi-copy host-selective ACT-toxin biosynthesis gene in the tangerine pathotype of Alternaria alternate using RNA silencing. Mol. Plant-Microbe Interact., 21: 1511-1599.
  2. Iida Y. et al. (2008) Nitrite reductase gene upregulated during conidiation is involved in macroconidium formation in Fusarium oxysporum. Phytopathology, 98: 1099-1106.
  3. Harimoto Y. et al. (2007) Expression profiles of genes encoded by the supernumerary chromosome controlling AM-toxin biosynthesis and pathogenicity in Alternaria alternata. Mol. Plant-Microbe Interact., 20: 1463-1476.
  4. Imazaki I. et al. (2007) Fow2, a Zn(II)2Cys6-type transcription regulator, controls plant infection of the vascular wilt fungus Fusarium oxysporum. Mol. Microbiol., 63: 737-753.
  5. Iida Y. et al. (2006) Identification of genes up-regulated during conidiation of Fusarium oxysporum through expressed sequence tag analysis. Fungal Genet. Biol., 43: 179-189.
  6. Ito K. et al. (2004) Dissection of the host range of the fungal plant pathogen Alternaria alternata by modification of secondary metabolism. Mol. Microbiol., 52: 399-411.
  7. Ohara T. & Tsuge T. (2004) FoSTUA, encoding a basic helix-loop-helix protein, differentially regulates development of three kinds of asexual spores, macroconidia, microconidia, and chlamydospores, in the fungal plant pathogen Fusarium oxysporum. Eukaryot. Cell, 3: 1412-1422.
  8. Ohara T. et al. (2004) REN1 is required for development of microconidia and macroconidia, but not of chlamydospores, in the plant pathogenic fungus Fusarium oxysporum. Genetics, 166: 113-124.
  9. Hatta R. et al. (2002) A conditionally dispensable chromosome controls host-specific pathogenicity in the fungal plant pathogen Alternaria alternata. Genetics, 161: 59-70.
  10. Inoue I. et al. (2002) Plant colonization by the vascular wilt fungus Fusarium oxysporum requires FOW1, a gene encoding a mitochondrial protein. Plant Cell 14: 1869-1883.

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