fumigatus protein expression following exposure to gliotoxin, Schrettl et al. (2010) identified a threefold upregulation of GliT, a gliotoxin oxidoreductase and a component of the gliotoxin biosynthetic cluster. Subsequent targeted deletion of this gene confirmed its key role in self-protection against gliotoxin toxicity in A. fumigatus and also established a role for gliT in gliotoxin biosynthesis (Scharf et al., 2010; Schrettl et al., 2010). Interestingly, two isoforms of GliT were detected in A. fumigatus; however, the biological significance of this observation BMS 354825 remains to be established. In a comprehensive analysis of altered protein expression during A. fumigatus biofilm formation, Bruns et al. (2010) found that at 48 h in mature

biofilms, the expression of genes and proteins involved in secondary metabolite biosynthesis in general, and gliotoxin biosynthesis in particular (e.g. GliT), is upregulated. This suggests a protective role for GliT, as gliotoxin was also detected in A. fumigatus biofilms. The expression of GliG, a glutathione s-transferase (GST), was also elevated; however, the recent demonstration that this gene is only involved in gliotoxin biosynthesis, and not self-protection (Davis et al., 2011), underlines the key role of GliT in fungal self-protection against gliotoxin. Metarhizium spp. are important entomopathogenic fungi that have significant potential for use as alternatives to chemical insecticides for agricultural pest control

(Pedrini et al., 2007); however, while genome and EST sequence analyses have been published (Wang ABT-199 et al., 2009; Gao et al., 2011), few proteomic studies had been undertaken. However, recent studies are beginning to reveal the proteome of this fungus, which may have a significant impact on the future use of Metarhizium spp. Barros et

al. (2010) have used 2D-PAGE to detect 1130 ± 102 and 1200 ± 97 protein spots for Metarhizium acridum conidia and mycelia, respectively. Approximately 35% of protein spots were common to both developmental stages, with the remainder equally occurring only in either conidia or mycelia. Of 94 proteins identified by MALDI-ToF/ToF MS, heat shock proteins and an allergen (Alt a 7) were uniquely NADPH-cytochrome-c2 reductase identified in conidia, while metabolic proteins (e.g. transaldolase, protein disulphide isomerase and phosphoglycerate kinase) were primarily identified in mycelia. Barros et al. (2010) noted the differences in the extent of expression of identical proteins, and isoform occurrence, between conidia and mycelia. Although not discussed in detail, this observation highlights the requirement for future quantitative proteomic studies to reveal the biological significance of altered protein expression. Interestingly, most protein identifications were achieved by comparison against homologues or orthologues in related fungal species, because few Metarhizium sequence entries were present in the NCBInr data database when this study was undertaken; however, genome availability (Gao et al.