Gliotoxin effects on fungal growth: Mechanisms and exploitation
- 作者：Stephen Carberry ; Emer Molloy ; Stephen Hammel ; Grainne O’ ; Keeffe ; Gary W. Jones ; Kevin Kavanagh ; Sean Doyle ; sean.doyle@nuim.ie ;
- 关键词：Aspergillus fumigatus ; Proteomics ; Natural products ; Aspergillus ; Yeast ; NRPS
- 刊名：Fungal Genetics and Biology
- 出版年：2012
- 期刊代码：116_10871845
- 类别：abs
- 出版时间：April, 2012
- 卷：49
- 期：4
- 页码：302-312
- 文件大小：1052 K
摘要
Although initially investigated for its antifungal properties, little is actually known about the effect of gliotoxin on Aspergillus fumigatus and other fungi. We have observed that exposure of A. fumigatus to exogenous gliotoxin (14 渭g/ml), under gliotoxin-limited growth conditions, results in significant alteration of the expression of 27 proteins (up- and down-regulated >1.9-fold; p < 0.05) including de novo expression of Cu, Zn superoxide dismutase, up-regulated allergen Asp f3 expression and down-regulated catalase and a peroxiredoxin levels. Significantly elevated glutathione GSH levels (p < 0.05), along with concomitant resistance to diamide, were evident in A. fumigatus 螖gliT, lacking gliotoxin oxidoreductase, a gliotoxin self-protection gene. Saccharomyces cerevisiae deletents (螖sod1 and 螖yap1) were hypersensitive to exogenous gliotoxin, while 螖gsh1 was resistant. Significant gliotoxin-mediated (5 渭g/ml) growth inhibition (p < 0.001) of Aspergillus nidulans, Aspergillus terreus, Aspergillus niger, Cochliobolus heterostrophus and Neurospora crassa was also observed. Growth of Aspergillus flavus, Fusarium graminearum and Aspergillus oryzae was significantly inhibited (p < 0.001) at gliotoxin (10 渭g/ml), indicating differential gliotoxin sensitivity amongst fungi. Re-introduction of gliT into A. fumigatus 螖gliT, at a different locus (ctsD; AFUA_4G07040, an aspartic protease), with selection on gliotoxin, facilitated deletion of ctsD without use of additional antibiotic selection markers. Absence of ctsD expression was accompanied by restoration of gliT expression, and resistance to gliotoxin. Thus, we propose gliT/gliotoxin as a useful selection marker system for fungal transformation. Finally, we suggest incorporation of gliotoxin sensitivity assays into all future fungal functional genomic studies.