[Sequence characterization and differential expression of a glutathione S-transferase gene vv-gto1 from Volvariella volvacea].

OBJECTIVE: Based on the analysis of omics data of Volvariella volvacea, a gene encoding glutathione S- transferase (GSTs) named vv-gtol was obtained. To reveal the role of GSTs in the growth and development in edible fungi, the structure, the sequence characters and the expression profile of a GST gene vv-gto1 of Volvariella volvacea were analyzed.

METHODS: ZOOM software was used to map sequencing read (reads) from genome and transcriptome against the splicing sequence of genome, to confirm the complete length and the accuracy of the gene sequence, and to visualize gene structure. The MEGA 5.1 was used to do the multiple sequence alignment and phylogenetic tree analysis. Real time fluorescent quantitative PCR was used to determine the expression levels of vv-gtol at different growth periods of Volvariella volvacea.

RESULTS: The full sequence of vv-gtol covered 2083 bp, containing 11 exons and 10 introns, and encoded a protein with 356 amino acids. 5'UTR was 305 bp which contains one intron region, and 3'UTR was 86bp. Two intron retentions could be recognized during RNA processing, and the transcripts formed by the intron retention could not translate the correct conservative functional domains. The full-length of vv-gtol had more than 50 accurate positioning genome sequencing reads, suggesting that genome sequencing and assembly results are accurate and reliable. The phylogenetic tree showed that GTO1 of Volvariella volvacea belonged to the subclass I of the Omega class of glutathione S-transferase superfamily, and had the closest relationship with GTO1 and GTO2 in Phanerochaete chrysosporium. The analysis of digital gene expression profiling, fluorescence quantitative PCR and proteomics showed that vv-gtol had the highest expression level in the heterokaryotic hyphae.

CONCLUSIONS: This is the first time to obtain a gene encoding glutathione S-transferase from Volvariella volvacea which belongs to Omega class. Our study showed that the gene may play an important role during the special biological functions of heterokaryotic hyphae. This study also suggested that Volvariella volvacea heterokaryotic hyphae in H1521 had stronger resistance ability than other samples. In addition, vv-gto1 could form different alternative splicesome to regulate gene transcription and translation, and ultimately affect the function of the protein.