Changes in transcriptome expression profiles and functional analysis of differentially expressed genes during mycelium-to-yeast transformation of Sporothrix schenckii

Abstract

Objective To compare and analyze the differences in the transcriptomics between mycelium and early yeast phases of Sporothrix schenckii (S. schenckii) , and to realize the changes in transcriptome expression profiles during mycelium-to-yeast transformation. Methods A standard strain of S. schenckii (ATCC 10268) was subjected to 96-hour culture with Sabouraud medium at 25 ℃ or 36-hour culture with brain-heart infusion medium at 37 ℃ to obtain the mycelium and yeast form of S. schenckii, and then, their transcriptomes were sequenced. Functional annotation was performed for screened unigenes by comparison using several databases (such as NR, Swiss-Prot, KEGG, COG, KOG, GO and Pfam) , coding sequence prediction, and gene expression analysis in each sample. Finally, the differentially expressed genes were subjected to pattern clustering, functional annotation and enrichment analysis. Results A total of 14.76 Gb valid data (clean data) were obtained, and functional annotation results were acquired in 28 094 of 43 863 assembled unigene clusters. Compared with S. schenckii in mycelium phase, there were 10 969 up-regulated genes and 199 down-regulated genes in S. schenckii in yeast phase. These differentially expressed genes were involved in protein phosphorylation, intracellular protein transport, cellular protein modification, small guanosine triphosphate-mediated signal transduction, vesicle-mediated transport, translation, intracellular signal transduction, microtubule formation, adenosine triphosphate synthesis, coupled proton transport and so on. Sixteen genes in the mitogen-activated protein kinase (MAPK) pathway and two-component signaling pathway, which were two important signal transduction pathways involved in fungal morphogenesis, and 16 genes involved in chitin synthesis and metabolism were all confirmed to be up-regulated in S. schenckii in yeast phase. Conclusions Compared with S. schenckii in mycelium phase, great changes in gene expression profiles were observed in S. schenckii in yeast phase. These differentially expressed genes are involved in many functions, suggesting that the dimorphic transition of S. schenckii is regulated by a multi-gene network system. Key words: Sporothrix; Hyphae; Transcriptome; Gene expression profiling; Differential gene expression analysis; Yeast phase