Abstract: 【Aim】To establish the transcriptome databases of three species of the genus Sclomina, analyze the expression differences of transcriptomes among related species, and investigate the interspecific divergence at the transcriptome level.【Methods】The Illumina HiSeq^TM4000 high-throughput sequencing platform was used for transcriptome sequencing in the three Sclomina species, S. erinacea, S. xingrensis and S. guangxiensis. The gene function annotation was conducted by using Nr, Swiss-Prot, COG/KOG and KEGG databases. The GO functional annotation and KEGG pathway enrichment analysis were performed for the interspecific differentially expressed genes (DEGs).【Results】A total of 42 215 unigenes were obtained by transcriptome sequencing of S. erinacea, S. xingrensis and S. guangxiensis. A total of 21 117 genes were annotated in the above four databases (number of genes: Nr, 20 522; Swiss-Prot, 15 550; COG/KOG, 13 969, KEGG, 10 850). There were 3 390 DEGs (803 up-regulated, 2 587 down-regulated) in the S. xingrensis vs S. erinacea transcriptomes, 12 543 DEGs (6 639 up-regulated, 5 904 down-regulated) in the S. xingrensis vs S. guangxiensis transcriptomes, and 3 580 DEGs (2 485 up-regulated, 1 095 down-regulated) in the S. erinacea vs S. guangxiensis transcriptomes. GO functional annotation result showed that all of the above DEGs were annotated into three functional classes including biological process, cellular component and molecular function, and some functional subclasses. The DEGs in the S. xingrensis vs S. erinacea transcriptomes were annotated into 50 functional subclasses, such as metabolic process, cell and cell part, and more genes were down-regulated, and a few genes were up-regulated. The DEGs in the S. xingrensis vs S. guangxiensis transcriptomes were annotated into 54 functional subclasses, such as biological process, cell part and cell. The DEGs in the S. erinacea vs S. guangxiensis transcriptomes were annotated into 46 functional subclasses, such as cell part and metabolic process. A total of 6 254 DEGs were annotated to KEGG metabolic pathways involving several different metabolic pathways, including metabolic pathway, drug metabolism-cytochrome P450, ribosome, etc. A total of 702 DEGs in the S. xingrensis vs S. erinacea transcriptomes were enriched in 164 KEGG pathways. A total of 2 091 DEGs in the S. xingrensis vs S. guangxiensis transcriptomes were enriched to 201 KEGG pathways. A total of 865 DEGs in the S. erinacea vs S. guangxiensis transcriptomes were enriched to 129 KEGG pathways. The number of DEGs enriched in metabolic pathway, drug metabolism-cytochrome P450 and ribosome in the S. xingrensis vs S. guangxiensis transcriptomes was the highest.【Conclusion】This study results enrich the molecular biological data of the genus Sclomina. At the level of transcriptome, the interspecies difference in S. erinacea, S. xingrensis and S. guangxiensis, and the actual situation of species divergence in this genus Sclomina are explored.

Key words: Sclomina, high-throughput sequencing, transcriptome, differentially expressed genes