title: Mannitol induces the conversion of conidia to chlamydospore-like structures that confer enhanced tolerance to heat, drought, and UV in Gibberella zeae.
abstract: Fungi use mannitol to store carbon, balance redox, and mannitol serves as an antioxidant. Several fungi also increase stress tolerance by accumulating mannitol. The results of this study showed that conidia of the cereal head blight fungus Gibberella zeae were readily changed to chlamydospore-like structures (CLS) in cultures supplemented with high amounts of mannitol. CLS cellular features were atypical of chlamydospores, but accumulated high levels of glycogen, lipids, and chitin in the cytoplasm. In addition, CLS exhibited increased tolerance to environmental stresses, including UV, heat, and drought compared to normal conidia. Molecular approaches revealed that several genes associated with lipid metabolism, signal transduction, acetyl-CoA production, and chitin synthesis were involved in CLS formation. This is the first report to characterize conidia modifications similar to chlamydospores in G. zeae applying histological and molecular approaches. The results suggest CLS serve a role in G. zeae survival strategies under hot and dry field conditions.
authors.affiliation: Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Hokyoung
authors.initials: H
authors.lastname: Son
authors.forename: Jungkwan
authors.initials: J
authors.lastname: Lee
authors.forename: Yin-Won
authors.initials: YW
authors.lastname: Lee
mesh_terms: D000105:Acetyl Coenzyme A / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D002686:Chitin / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D055864:Droughts; D005874:Gibberella / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006003:Glycogen / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D050356:Lipid Metabolism; D008055:Lipids / Q000235:genetics; D008353:Mannitol / Q000378:metabolism*; D015398:Signal Transduction; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D014466:Ultraviolet Rays
chemical_list: D008055:Lipids; D002686:Chitin; D008353:Mannitol; D000105:Acetyl Coenzyme A; D006003:Glycogen