基于转录组测序技术挖掘长吻鮠生长关键基因

Mining of key genes related to growth of Chinese longsnout catfish (Leiocassis longirostris) based on transcriptome analysis

关键词:  长吻鮠  鱼类生长  转录组测序  神经内分泌因子

Key words:  Leiocassis longirostris  Fish growth  Transcriptome sequencing  Neuroendocrine factors

摘要:

为挖掘我国名优鱼类长吻鮠 (Leiocassis longirostris)生长相关基因，本研究运用Illumina高通量测序技术比较分析了快速生长组[平均体质量为(534.02±53.68) g]和缓慢生长组[平均体质量为(108.41±4.96) g]各9尾长吻鮠的脑组织基因表达谱。测序共获得267 404 674个高质量测序片段(clean reads)，通过2种不同生长速率长吻鮠脑组织转录组比较筛选出518个差异表达基因，其中，412 个基因表达量上调，106个基因表达量下调。对12个差异表达基因进行实时荧光定量PCR验证的结果与转录组测序结果一致。GO功能分类显示，大量差异表达基因富集到生长(growth)、生长因子活性(growth factor activity)和激素介导的信号通路(hormone-mediated signaling pathway) GO条目中。KEGG富集分析显示，一些差异表达基因在MAPK信号通路(MAPK signaling pathway)、转化生长因子β信号通路(TGF-beta signaling pathway)、钙离子信号通路(calcium signaling pathway)和神经活性配体–受体相互作用(neuroactive ligand-receptor interaction)等途径中富集。根据GO功能注释和KEGG富集分析，筛选出gnrh、thr、egr1、fgf18、sst、gipr、cart和crf等基因是调控长吻鮠生长发育的关键候选基因。本研究结果为后续深入研究长吻鮠生长调控机制提供了重要的参考资料。

Abstract:

The Chinese longsnout catfish (Leiocassis longirostris) is a rare and valuable freshwater fish wildly distributed throughout China. Fish growth is one of the most economically important traits in fish farming. Cultured fish with high growth performance can often bring direct economic benefits while meeting human food demand. The hypothalamus is an important regulatory organ in fish metabolic processes and endocrine activities, directly or indirectly regulating fish growth. Although significant research on L. longirostris has been reported, the molecular mechanisms and key genes involved in its growth are still unclear. Therefore, we performed comparative transcriptomics analysis using Illumina high throughput sequencing technology and analyzed transcript profiles of the brains from fast-growth (FG) with average body mass of (534.02±53.68) g, and slow-growth (SG) with average body mass og (108.41±4.96) g L. longirostris individuals. A total of 267 404 674 clean reads were generated, and 518 differentially expressed genes were identified, of which 412 genes were up-regulated and 106 genes were down-regulated in fast-growth fishes. Then, we subjected all these differentially expressed genes to GO term enrichment and KEGG pathway analysis to find the underlying function annotation. Based on Gene Ontology analysis, plenty of differentially expressed genes were enriched in growth, growth factor activity, and hormone-mediated signaling pathway. KEGG enrichment analysis indicated that some differentially expressed genes involved in MAPK signaling pathway, TGF-beta signaling pathway, calcium signaling pathway, and neuroactive ligand-receptor interaction were enriched. With the differentially expressed genes identified from GO and KEGG enrichment analysis, several key genes related to the growth of L. longirostris were screened, such as gnrh, thr, egr1, fgf18, sst, gipr, cart, and crf. The results of this study enriched the gene resources and provided valuable references for further study on the regulation mechanism of growth of L. longirostris.