###### Abstract  
Recent transcriptomic profiling has revealed importance membrane transporters such as ATP-binding cassette (ABC) transporters in fungal heterotrophic mycoparsisites. In this study, RNA-Seq allowed rapid detection of ABC transcripts involved in biotrophic mycoparsitism of _Sphaerodes mycoparsistica_ against the phytopathogenic and mycotoxigenic _Fusarium graminarum_ host, the causal agent of Fusarium head blight (FHB). Transcriptomic analyses of highly expressed _S. mycoparsistica_ genes, and their phylogenetic relationships with other eukaryotic fungi, portrayed the ABC transporters' evolutionary paths towards biotrophic mycoparsatism. Prior to the in silico phylogenetic analyses, transmission electron microscopy (TEM) was used to confirm the formation of approsarium/haustorium infection structures in _S. mycoparsistica_ during early (1.5 d and 3.5 d) stages of mycoparsitism. Transcripts encoding biotherophy-associated secreted proteins did uncover the enrolment of ABC transporter genes in this specific biocontrol mode of action, while tandem ABC and BUB2 (non-ABC) transcripts seemed to be proper for approsserium development. The next-generation HiSeq transcriptomic profiling of the mycoparsistic hypha samples, revealed 81 transcripts annotated to ABC transporters consisting of a variety of ABC-B (14%), ABC-C (22%), and ABC-G (23%), and to ABC-A, ABC-F, aliphatic sulfonates importer (TC 3.A.1.17.2), BtuF, ribose importer (TC 3.A.1.2.1), and unknown families. The most abundant transcripts belonged to the multidrug resistance reporter (TC 3.A.1.201) subfamily of the ABC-B family, the conjugate transporter (TC 3.A.1.208) subfamily of the ABC-C family, and the pleiotropic drug resistance (PDR) (TC 3.A.1.205) subfamily of the ABC-G family. These findings highlight the significance of ABC transporter genes that control cellular detoxification against toxic substances (e.g., chemical pesticides and mycotoxins) in sustaining a virulence of _S. mycoparsistica_ for effective biotrophic mycoparsitism on the _F. graminarum_ host. The findings of this study provide clues to better understand the biotrophic mycoparsitism of _S. mycoparsistica_ interacting with the _Fusarium_ host, which implies that the ABC transporter group of key proteins is involved in the mycoparsite's virulence and multidrug resistance to toxic substances including cellular detoxification. R +
Footnote †: journal: Applied Sciences  
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depends on the parasite's mode of action and its effect on a host as well as its host compatibility and specificity. Necrotrophic mycopparasitism is an aggressive mode of action where a mycopparasite kills or destroys a fungal prey and acquires or absorbs nutrients from the killed host cells, while biotrophic mycopparasitism is a more sophisticated mode of action combining a destructive and balanced strategy in which a mycopparasite lets nutrients of host cells flow out through intimate relationships between a parasite and a host. Necrotrophic mycopparasites are also known as generalists and include several _Trichoderma_ species such as _T. harzianum, T. viride, T. virens, T. atroviride, T. koningii, T. gamsii_, and _Clonostachys rosea_, whereas biotrophic mycopparasites are known as specialists and include _Ampelomyces quisqualis_ and _Sphaerodes_ species such as _S. mycopparasitica, S. quadrangularis_, and _S. retispora_ var. _retispora_[7]. Recently, biocontrol science has shifted from these non-specific to specific biocontrol fungal agents such as mycopparasitic _Ampelomyces_ against powdery mildew (Erysiphales), _Sphaerodes_ against _Fusaria_ pathogens, and mycotoxins in cereal grains. _Sphaerodes mycopparasitica_ is a biotrophic polyphagous mycopparasite of plant pathogenic and mycotoxigenic _Fusarium_ species [2]. _S. mycopparasitica_ produces hook-shaped contact structures [8] that eventually penetrate the host hyphae of the FHB _Fusarium_ species through presumptive appressorium/haustorium-like structures during mycopparasitism.