Abstract
Role of efflux-mediated toxin resistance to trichothecenes is known in trichothecene-producing species. However, the role of trichothecene efflux pump homologues in non-producing fusaria such as F. oxysporum and F. proliferatum was not investigated in detail. Analysis of the homologues of trichothecene efflux pump from multiple fungal species allowed us to uncover and catalogue functional gene copies of conserved structure. Putative Tri12 candidates in Fusarium oxysporum and F. proliferatum were characterised via expression profiling in response to different trigger compounds, providing supporting evidence for role of Tri12 homologues in the resistance to trichothecenes. Our analysis of Tri12 phylogeny also suggests that efflux-mediated trichothecene resistance is likely to predate the divergence of Trichoderma and Fusarium species. On the regulatory level, we posit that the increased tolerance of trichothecenes by F. oxysporum is possibly related to the decoupling of Tri12 homologue expression from pH, due to the deletion of PACC/RIM101 transcription factor binding site in its promoter region.
Highlights
Mycotoxins are bioactive fungal secondary metabolites which are typically viewed mainly through the lens of their harmful properties to humans and livestock
We posit that the increased tolerance of trichothecenes by F. oxysporum is possibly related to the decoupling of Tri12 homologue expression from pH, due to the deletion of PACC/RIM101 transcription factor binding site in its promoter region
In order to obtain supporting evidence for functionality of divergent Tri12 homologues in fujikuroi and oxysporum complex, we investigated the expression of F. proliferatum and F. oxysporum homologues in response to varying stimuli
Summary
Mycotoxins are bioactive fungal secondary metabolites which are typically viewed mainly through the lens of their harmful properties to humans and livestock. In this context, there is evidence demonstrating that trichothecene biosynthesis has impact on fungus-fungus competition. Ramakrishna et al (1996) found that during competition between F. sporotrichioides (producer of T-2 toxin) and two other fungi: A. flavus and Penicillium verrucosum the growth of F. sporotrichioides was negatively affected but paradoxically the production of T-2 mycotoxin was stimulated. The results illustrated that mycotoxins can inhibit the mitochondrial membrane potential, translation and levels of reactive oxygen species in fungi, in a dose-dependent manner
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
