Identification of yeast genes that confer resistance to chitosan oligosaccharide (COS) using chemogenomics

BMC Genomics

Research Article

Ana Conesa¹  J Timothy Westwood²  Maria DLA Jaime²  Anna Y Lee³  Guri Giaever⁴  Corey Nislow⁵  Marinella Gebbia⁶  Lawrence E Heisler⁶  Luis Vicente Lopez-Llorca⁷  Michael Proctor⁸ 

[1] Bioinformatics and Genomics Department, Prince Felipe Research Centre, Valencia, Spain;Department of Cell and Systems Biology, University of Toronto, Mississauga, Ontario, Canada;Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada;Terrence Donnelly Centre for Cellular and Biomedical Research, University of Toronto, Toronto, Ontario, Canada;Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada;Terrence Donnelly Centre for Cellular and Biomedical Research, University of Toronto, Toronto, Ontario, Canada;Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada;Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada;Terrence Donnelly Centre for Cellular and Biomedical Research, University of Toronto, Toronto, Ontario, Canada;Laboratory of Plant Pathology, Multidisciplinary Institute for Environmental Studies (MIES) Ramon Margalef, Department of Marine Sciences and Applied Biology, University of Alicante, Alicante, Spain;Stanford Genome Technology Center, Palo Alto, California, USA;

关键词: Saccharomyces cerevisiae;    Chitosan oligosaccharide;    Antifungal resistance;    ARL1;    Chemogenomics;    Haploinsufficiency profiling (HIP);    Homozygous profiling (HOP);    Multi-copy suppression profiling (MSP);    Transcriptional analysis;    Stress response;   

DOI  :  10.1186/1471-2164-13-267

 received in 2012-01-04, accepted in 2012-04-25,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundChitosan oligosaccharide (COS), a deacetylated derivative of chitin, is an abundant, and renewable natural polymer. COS has higher antimicrobial properties than chitosan and is presumed to act by disrupting/permeabilizing the cell membranes of bacteria, yeast and fungi. COS is relatively non-toxic to mammals. By identifying the molecular and genetic targets of COS, we hope to gain a better understanding of the antifungal mode of action of COS.ResultsThree different chemogenomic fitness assays, haploinsufficiency (HIP), homozygous deletion (HOP), and multicopy suppression (MSP) profiling were combined with a transcriptomic analysis to gain insight in to the mode of action and mechanisms of resistance to chitosan oligosaccharides. The fitness assays identified 39 yeast deletion strains sensitive to COS and 21 suppressors of COS sensitivity. The genes identified are involved in processes such as RNA biology (transcription, translation and regulatory mechanisms), membrane functions (e.g. signalling, transport and targeting), membrane structural components, cell division, and proteasome processes. The transcriptomes of control wild type and 5 suppressor strains overexpressing ARL1, BCK2, ERG24, MSG5, or RBA50, were analyzed in the presence and absence of COS. Some of the up-regulated transcripts in the suppressor overexpressing strains exposed to COS included genes involved in transcription, cell cycle, stress response and the Ras signal transduction pathway. Down-regulated transcripts included those encoding protein folding components and respiratory chain proteins. The COS-induced transcriptional response is distinct from previously described environmental stress responses (i.e. thermal, salt, osmotic and oxidative stress) and pre-treatment with these well characterized environmental stressors provided little or any resistance to COS.ConclusionsOverexpression of the ARL1 gene, a member of the Ras superfamily that regulates membrane trafficking, provides protection against COS-induced cell membrane permeability and damage. We found that the ARL1 COS-resistant over-expression strain was as sensitive to Amphotericin B, Fluconazole and Terbinafine as the wild type cells and that when COS and Fluconazole are used in combination they act in a synergistic fashion. The gene targets of COS identified in this study indicate that COS’s mechanism of action is different from other commonly studied fungicides that target membranes, suggesting that COS may be an effective fungicide for drug-resistant fungal pathogens.

【 授权许可】

Unknown   
© Jaime et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.