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Eukaryotic Cell, January 2009, p. 116-127, Vol. 8, No. 1
1535-9778/09/$08.00+0 doi:10.1128/EC.00176-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
GzSNF1 Is Required for Normal Sexual and Asexual Development in the Ascomycete Gibberella zeae
,
Seung-Ho Lee,1
Jungkwan Lee,1
Seunghoon Lee,1
Eun-Hee Park,2
Ki-Woo Kim,3
Myoung-Dong Kim,2
Sung-Hwan Yun,4* and
Yin-Won Lee1*
Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, South Korea,1 School of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701, South Korea,2 National Instrumentation Center for Environmental Management, Seoul National University, Seoul 151-921, South Korea,3 Department of Medical Biotechnology, Soonchunhyang University, Asan 336-745, South Korea4
Received 29 May 2008/ Accepted 14 November 2008
The sucrose nonfermenting 1 (SNF1) protein kinase of yeast plays a central role in the transcription of glucose-repressible genes in response to glucose starvation. In this study, we deleted an ortholog of SNF1 from Gibberella zeae to characterize its functions by using a gene replacement strategy. The mycelial growth of deletion mutants (
GzSNF1) was reduced by 21 to 74% on diverse carbon sources. The virulence of GzSNF1 mutants on barley decreased, and the expression of genes encoding cell-wall-degrading enzymes was reduced. The most distinct phenotypic changes were in sexual and asexual development. GzSNF1 mutants produced 30% fewer perithecia, which matured more slowly, and asci that contained one to eight abnormally shaped ascospores. Mutants in which only the GzSNF1 catalytic domain was deleted had the same phenotype changes as the GzSNF1 strains, but the phenotype was less extreme in the mutants with the regulatory domain deleted. In outcrosses between the GzSNF1 mutants, each perithecium contained 
70% of the abnormal ascospores, and 50% of the asci showed unexpected segregation patterns in a single locus tested. The asexual spores of the GzSNF1 mutants were shorter and had fewer septa than those of the wild-type strain. The germination and nucleation of both ascospores and conidia were delayed in GzSNF1 mutants in comparison with those of the wild-type strain. GzSNF1 expression and localization depended on the developmental stage of the fungus. These results suggest that GzSNF1 is critical for normal sexual and asexual development in addition to virulence and the utilization of alternative carbon sources.
* Corresponding author. Mailing address for Yin-Won Lee: Department of Agricultural Biotechnology and Center for Agricultural Bio-materials, Seoul National University, Seoul 151-921, South Korea. Phone: (82) 2 880 4671. Fax: (82) 2 873 2317. E-mail: lee2443{at}snu.ac.kr. Mailing address for Sung-Hwan Yun: Department of Medical Biotechnology, Soonchunhyang University, Asan 336-745, South Korea. Phone: (82) 41 530 1288. Fax: (82) 41 544 1289. E-mail: sy14{at}sch.ac.kr
Published ahead of print on 21 November 2008.
Supplemental material for this article may be found at http://ec.asm.org/.
Eukaryotic Cell, January 2009, p. 116-127, Vol. 8, No. 1
1535-9778/09/$08.00+0 doi:10.1128/EC.00176-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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