微泡菌属菌株YPW1和YPW16多糖降解特性分析

Characterization of genes involved in polysaccharide degradation by Microbulbifer sp. YPW1 and YPW16

摘要:

【背景】海洋环境中分离到的微泡菌属菌株具有多糖降解能力，在环境中可以作为糖类代谢的重要执行者参与海洋碳循环过程。【目的】测定2株微泡菌属菌株的多糖降解活性，通过与微泡菌属其他菌株基因组比较分析2株菌的多糖降解基因特征。【方法】通过3,5-dinitrosalicylic acid (DNS)定糖法测定多糖降解活性，同时利用高通量测序技术对菌株基因组序列进行测定与组装，并与其他基因组注释结果进行比较分析。【结果】分离得到2株微泡菌属菌株YPW1和YPW16，二者均为潜在新种。结果表明，菌株YPW1能够降解琼胶、褐藻胶、果胶、几丁质、木聚糖、淀粉、普鲁兰等7种多糖，而菌株YPW16仅可降解淀粉和普鲁兰。基因组分析表明，YPW1具有上述7种多糖的降解酶基因，但菌株YPW16只具有淀粉酶与普鲁兰酶降解基因。相较于其他微泡菌属菌株，菌株YPW1多糖降解范围、多糖降解酶基因种类与丰度较高，但菌株YPW16多糖降解范围却较为狭窄。由此可知，多糖降解酶基因在微泡菌属基因组中的分布差异性较大。【结论】本研究为微泡菌属提供了2株潜在的新型菌株资源，为生物多糖降解提供了生化工具，也为研究微泡菌属菌株中多糖降解基因分布与相关菌属的生态功能奠定基础。

Abstract:

[Background] Microbulbifer species isolated from the marine environments have the ability to degrade polysaccharides. They participate in the marine carbon cycle as an important player of carbohydrate metabolism in the environment. [Objective] To analyze the polysaccharide-degrading activities and genomics information of two Microbulbifer strains. [Methods] The 3,5-dinitrosalicylic acid colorimetry (DNS method) was employed to determine the polysaccharide-degrading activity. High-throughput sequencing was performed to sequence and assemble the genome sequence of the strains. [Results] Two strains of Microbulbifer species, namely YPW1 and YPW16, were isolated in this work, both of which were potential new species. YPW1 degraded 7 polysaccharides (agar, alginate, pectin, chitin, xylan, starch, and pullulan), while YPW16 only degraded starch and pullulan, with the activity lower than YPW1 under the experimental conditions. The genome comparison with other Microbulbifer strains showed that YPW1 had a wider polysaccharide degradation range due to its abundant genes for polysaccharide degradation. However, the polysaccharide degradation range of YPW16 was narrower. Moreover, the genes involved in polysaccharide degradation presented uneven distribution in the genomes of Microbulbifer species. [Conclusion] This study provided two potential new strain resources of Microbulbifer and a biological tool for polysaccharide degradation, laying a foundation for studying the distribution of polysaccharide degradation genes and the ecological functions of Microbulbifer.