Gibberella zeae chitin synthase genes, GzCHS5 and GzCHS7, are required for hyphal growth, perithecia formation, and pathogenicity.
Gibberella zeae causes Fusarium head blight of cereal crops, and sexual spores of the fungus play an important role as primary inocula. We isolated a restriction enzyme-mediated integration (REMI) transformant, ZH431, of G. zeae with defects in perithecia formation and virulence. Integration of the REMI vector resulted in disruption of GzCHS7 gene, which encodes a putative class VII chitin synthase with high similarity to Fusarium oxysporum ChsVb. A second chitin synthase, GzCHS5, is adjacently located in a head-to-head configuration with GzCHS7, and its deduced protein sequence showed similarity with a class V chitin synthase in F. oxysporum. Neither DeltaGzChs5 nor DeltaGzChs7 mutants produced perithecia or caused disease on barley heads. Microscopic observation revealed that both mutants formed balloon-shaped hyphae and intrahyphal hyphae and that cell wall rigidity of the mutants was weaker than that of the wild-type strain. Transcription profiles of GzCHS5 and GzCHS7 were not altered in DeltaGzChs7 and DeltaGzChs5, respectively, suggesting that transcription regulations of the genes are independent of each other. Our results demonstrate that GzCHS5 and GzCHS7 are indispensable for perithecia formation and pathogenicity as well as normal septa formation and hyphal growth in G. zeae.
Kim
Jung-Eun
JE
Department of Agricultural Biotechnology, Centers for Fungal Pathogenesis and for Agricultural Biomaterials, Seoul National University, Seoul, 151-921, Korea.
Lee
Hyo-Jin
HJ
Lee
Jungkwan
J
Kim
Ki Woo
KW
Yun
Sung-Hwan
SH
Shim
Won-Bo
WB
Lee
Yin-Won
YW
D002687:Chitin Synthase / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005874:Gibberella / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D025301:Hyphae / Q000235:genetics / Q000378:metabolism*
D002687:Chitin Synthase