Transcriptomic profiling to identify genes involved in Fusarium mycotoxin Deoxynivalenol and Zearalenone tolerance in the mycoparasitic fungus Clonostachys rosea

Abstract

BackgroundClonostachys rosea strain IK726 is a mycoparasitic fungus capable of controlling mycotoxin-producing Fusarium species, including F. graminearum and F. culmorum, known to produce Zearalenone (ZEA) and Deoxynivalenol (DON). DON is a type B trichothecene known to interfere with protein synthesis in eukaryotes. ZEA is a estrogenic-mimicing mycotoxin that exhibits antifungal growth. C. rosea produces the enzyme zearalenone hydrolase (ZHD101), which degrades ZEA. However, the molecular basis of resistance to DON in C. rosea is not understood. We have exploited a genome-wide transcriptomic approach to identify genes induced by DON and ZEA in order to investigate the molecular basis of mycotoxin resistance C. rosea.ResultsWe generated DON- and ZEA-induced cDNA libraries based on suppression subtractive hybridization. A total of 443 and 446 sequenced clones (corresponding to 58 and 65 genes) from the DON- and ZEA-induced library, respectively, were analysed. DON-induced transcripts represented genes encoding metabolic enzymes such as cytochrome P450, cytochrome c oxidase and stress response proteins. In contrast, transcripts encoding the ZEA-detoxifying enzyme ZHD101 and those encoding a number of ATP-Binding Cassette (ABC) transporter transcripts were highly frequent in the ZEA-induced library. Subsequent bioinformatics analysis predicted that all transcripts with similarity to ABC transporters could be ascribed to only 2 ABC transporters genes, and phylogenetic analysis of the predicted ABC transporters suggested that they belong to group G (pleiotropic drug transporters) of the fungal ABC transporter gene family. This is the first report suggesting involvement of ABC transporters in ZEA tolerance. Expression patterns of a selected set of DON- and ZEA-induced genes were validated by the use of quantitative RT-PCR after exposure to the toxins. The qRT-PCR results obtained confirm the expression patterns suggested from the EST redundancy data.ConclusionThe present study identifies a number of transcripts encoding proteins that are potentially involved in conferring resistance to DON and ZEA in the mycoparasitic fungus C. rosea. Whilst metabolic readjustment is potentially the key to withstanding DON, the fungus produces ZHD101 to detoxify ZEA and ABC transporters to transport ZEA or its degradation products out from the fungal cell.

The complete mitochondrial genome of the important mycoparasiteClonostachys rosea(Hypocreales, Ascomycota)

“…(Kosawang et al 2014). Its nuclear genome and transcriptome analyses have been reported (Kosawang et al 2014;Karlsson et al 2015). The fungus is economically important and widely distributed in tropical and temperate zones.…”

Analysis of a suppressive subtractive hybridization library of Alternaria alternata resistant to 2-propenyl isothiocyanate

“…Another transcript induced by 2p-ITC codes for the regulatory protein CHK1, which is also involved in responses to DNA damage and cell survival [42]. In Clonostachys rosea, the CHK1 protein was induced in response to oxidative stress by toxins [43]. Because 2p-ITC is a compound causing oxidative stress, it is feasible that CHK1 was induced in A. alternata after the 2p-ITC treatment.…”

“…Therefore, it should be emphasized that even natural compounds could induce tolerance/resistance mechanisms in organisms in the same manner as synthetic chemical products if they were not used properly. In a study with fungal toxins Kosawang et al [43] using a SSH experimental approach reported 443 and 446 differentially expressed clones induced in Clonostachys rosea by deoxynivalenol (DON) and zearalenone (ZEA) toxins, respectively. DON induced proteins involved in the stress response as well as metabolic enzymes (cytochromes c oxidase and P450) while ZEA induced the detoxifying enzyme HD101 and ABC pleiotropic drug transporters.…”

Biological Control of Patulin by Antagonistic Yeast: A case study and possible model

“…According to Kosawang et al (2014), Zearalenone (ZEA) is an estrogenic-mimicing mycotoxin that exhibits antifungal growth. It is a common contaminant in cereal products particularly grains that are frequently infested by Fusarium spp (Brodehl et al, 2014).…”