关键词: 蜜蜂球囊菌, PacBio测序, RNA编辑, 转录因子, 融合基因

Abstract: 【Aim】 This study aims to identify and analyze transcription factors (TFs), fusion genes and RNA editing events in Ascosphaera apis mycelium (AaM) and spore (AaS) based on previously obtained PacBio single molecule real-time (SMRT) sequencing data, so as to further enrich the relevant information of A. apis and to offer theoretical basis for further investigation of their function. 【Methods】 Full-length transcripts in AaM and AaS were respectively aligned against Nr, Swiss-Prot and KEGG databases using BLASTx tool to gain protein sequences with the highest identity, which were then aligned to Plant TFdb database with hmmscan software to obtain the information of classification and annotation of TFs. Additionally, fusion_finder.py program contained in TOFU software was used for prediction of fusion genes, followed by analysis of their sequence and location information. RNA editing events in AaM and AaS were predicted using SAMtools, and then annotation of RNA editing events was performed with ANNOVAR software. Further, GO function and KEGG pathway annotation of genes located at the RNA editing sites was conducted using related bioinformatics software. 【Results】 A total of 213 TFs from 17 TF families were identified in AaS, and the C2H2 family was the largest. In AaM and AaS, 921 and 510 fusion genes were respectively identified. Additionally, in AaM and AaS, there were 510 shared fusion genes, while the numbers of specific ones were 411 and zero, respectively. In total, 547 and 191 RNA editing events were respectively identified in AaM and AaS, among them synonymous single nucleotide mutation was the most abundant type in AaM, while nonsynonymous single nucleotide mutation was the most abundant type in AaS. Moreover, 12 types of base substitution were identified in AaM, and the number of RNA editing events with C->T was the highest (158), while nine types of base substitution were identified in AaS, and the numbers of RNA editing events with C->T and G->T were the highest (both 42). In AaM and AaS, genes located at the RNA editing sites were involved in 19 and 24 GO functional terms as well as 11 and 20 KEGG pathways, respectively. 【Conclusion】 There are abundant TFs, fusion genes and RNA editing sites in mycelium and spore of A. apis. C2H2 family of TF has potential relationship with growth, development and cellular activity of mycelium and spore of A. apis. The base substitution types of RNA editing events in A. apis and other species are species-specific. RNA editing may play a role in growth and metabolism of mycelium and spore of A. apis.

Key words: Ascosphaera apis, PacBio sequencing, RNA editing, transcription factor, fusion gene