Journal of General Plant Pathology

, Volume 75, Issue 5, pp 353–358 | Cite as

Cytological characteristics of microconidia of Magnaporthe oryzae

  • Izumi Chuma
  • Takeshi Shinogi
  • Naoki Hosogi
  • Ken-ichi Ikeda
  • Hitoshi Nakayashiki
  • Pyoyun Park
  • Yukio Tosa
Fungal Diseases

Abstract

The inner cellular structure of microconidia of Magnaporthe oryzae was examined using fluorescent probes and electron microscopic techniques. The volume of the nucleus relative to the cell was significantly larger in microconidia than in macroconidia or vegetative hyphae, similar to observations for spermatia of other fungi. Selective fluorescent staining revealed that cytosolic RNA was less abundant in microconidia than in macroconidia and germ tubes, suggesting that general metabolic activity in microconidia is low. Consistently, GFP expression driven by the TrpC promoter was highly active during the formation of phialides and microconidia but gradually decreased as the microconidia matured. Such data suggest that microconidia are in a quiescent or dormant state.

Keywords

Magnaporthe oryzae Pyricularia oryzae Microconidia 

Notes

Acknowledgments

We thank Dr. H. Kato, former professor of Kobe University, for valuable suggestions and technical support.

References

  1. Barr ME (1977) Magnaporthe, Telimenella, and Hyponectria (Physosporellaceae). Mycologia 69:952–966CrossRefGoogle Scholar
  2. Couch BC, Kohn LM (2002) A multilocus gene genealogy concordant with host preference indicates segregation of a new species, Magnaporthe oryzae, from M. grisea. Mycologia 94:683–693CrossRefGoogle Scholar
  3. Fukumori Y, Nakajima M, Akutsu K (2004) Microconidia act the role as spermatia in the sexual reproduction of Botrytis cinerea. J Gen Plant Pathol 70:256–260CrossRefGoogle Scholar
  4. Hebert TT (1971) The perfect stage of Pyricularia grisea. Phytopathology 61:83–87CrossRefGoogle Scholar
  5. Kadotani N, Nakayashiki H, Tosa Y, Mayama S (2003) RNA silencing in the phytopathogenic fungus Magnaporthe oryzae. Mol Plant Microbe Interact 16:769–776CrossRefPubMedGoogle Scholar
  6. Kato H, Yamaguchi T, Nishihara N (1976) The perfect state of Pyricularia oryzae Cav. in culture. Ann Phytopathol Soc Jpn 42:507–510Google Scholar
  7. Kato H, Mayama S, Sekine R, Kanazawa E, Izutani Y, Urashima AS, Kunoh H (1994) Microconidium formation in Magnaporthe grisea. Ann Phytopathol Soc Jpn 60:175–185Google Scholar
  8. Kato H, Yamamoto M, Yamaguchi-Ozaki T, Kadouchi H, Iwamoto Y, Nakayashiki H, Tosa Y, Mayama S, Mori N (2000) Pathogenicity, mating ability and DNA restriction fragment length polymorphisms of Pyricularia populations isolated from Gramineae, Bambusideae and Zingiberaceae plants. J Gen Plant Pathol 66:30–47CrossRefGoogle Scholar
  9. Lowry RJ, Durkee TL, Sussman AS (1967) Ultrastructural studies of microconidium formation in Neurospora crassa. J Bacteriol 94:1757–1763PubMedGoogle Scholar
  10. Maheshwari R (1999) Microconidia of Neurospora crassa. Fungal Genet Biol 26:1–18CrossRefPubMedGoogle Scholar
  11. Park P, Unno K, Ishii H, Adachi Y, Kanematsu S, Uehara T (1996) An efficient and confirmative electron microscopy for observing the infection sites of fungi on plant tissues (Abstract in Japanese). Ann Phytopathol Soc Jpn 62:285Google Scholar
  12. Park P, Ishii H, Adachi Y, Kanematsu S, Ieki H, Umemoto S (2000) Infection behavior of Venturia nashicola, the cause of scab on Asian pears. Phytopathology 90:1209–1216CrossRefPubMedGoogle Scholar
  13. Ueyama A, Tsuda M (1975) Formation of the perfect state in culture of Pyricularia sp. from some graminaceous plants (preliminary report). Trans Mycol Soc Jpn 16:420–422Google Scholar
  14. Yaegashi H, Nishihara N (1976) Production of the perfect stage in Pyricularia from cereals and grasses. Ann Phytopathol Soc Jpn 42:511–515Google Scholar
  15. Yaegashi H, Udagawa S (1978) The taxonomical identity of the perfect state of Pyricularia grisea and its allies. Can J Bot 56:180–183CrossRefGoogle Scholar
  16. Zickler D, Arnaise S, Coppin E, Debuchy R, Picard M (1995) Altered mating-type identity in the fungus Podospora anserina leads to selfish nuclei, uniparental progeny, and haploid meiosis. Genetics 140:493–503PubMedGoogle Scholar

Copyright information

© The Phytopathological Society of Japan and Springer 2009

Authors and Affiliations

  • Izumi Chuma
    • 1
  • Takeshi Shinogi
    • 1
  • Naoki Hosogi
    • 1
  • Ken-ichi Ikeda
    • 1
  • Hitoshi Nakayashiki
    • 1
  • Pyoyun Park
    • 1
  • Yukio Tosa
    • 1
  1. 1.Laboratory of Plant Pathology, Graduate School of Agricultural SciencesKobe UniversityKobeJapan

Personalised recommendations