热带海洋学报 ›› 2022, Vol. 41 ›› Issue (2): 159-169.doi: 10.11978/2021040

• 海洋生物学 • 上一篇    下一篇

盐度对广盐型聚球藻K1生长及转录组的影响*

廖莹1,2(), 夏晓敏1,2()   

  1. 1. 热带海洋生物资源与生态重点实验室(中国科学院南海海洋研究所), 广东 广州 510301
    2. 中国科学院大学, 北京 100049
  • 收稿日期:2021-04-06 修回日期:2021-05-01 出版日期:2022-03-10 发布日期:2021-05-03
  • 通讯作者: 夏晓敏
  • 作者简介:廖莹(1994—), 女, 河北省衡水市人, 硕士研究生, 从事海洋生态学研究。email: liaoying18@mails.ucas.ac.cn
  • 基金资助:
    国家自然科学基金(41906131);中国科学院海洋大科学研究中心重点部署项目(COMS2020Q09);广东省自然科学基金面上项目(2019A1515011340)

Effects of salinity on the growth and transcriptome of euryhaline Synechococcus sp. K1*

LIAO Ying1,2(), XIA Xiaomin1,2()   

  1. 1. Key Laboratory of Tropical Marine Bio-resources and Ecology (South China Sea Institute of Oceanology, Chinese Academy of Sciences), Guangzhou 510301, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-04-06 Revised:2021-05-01 Online:2022-03-10 Published:2021-05-03
  • Contact: XIA Xiaomin
  • Supported by:
    Nature Science Foundation of China(41906131);Key Deployment Program of Center for Ocean Mega-Science, Chinese Academy of Sciences(COMS2020Q09);Guangdong Basic and Applied Basic Research Foundation(2019A1515011340)

摘要:

聚球藻是一类分布广泛、数量巨大的微微型浮游植物, 作为蓝藻的代表类群之一, 广泛分布于海洋以及河口区域, 并且具有丰富的色素多样性和遗传多样性。聚球藻根据盐度适应能力可划分为严格海洋型聚球藻和广盐型聚球藻。文章对分离自珠江口的聚球藻K1和南海寡营养海域的聚球藻YX02-1在不同盐度条件下的生长状况进行对比, 并根据ropC1标记基因分析K1和YX02-1的分类地位, 发现K1为广盐型聚球藻, 其在不同盐度下(10‰、13‰、18‰、25‰、33‰)均能生长; 而YX02-1为严格海洋型聚球藻, 在低于13‰的盐度下无法存活, 与其在河口的分布特征相一致。转录组分析显示, 低盐条件下广盐型聚球藻中合成渗透压调节分子的基因(ggpS、SPSstpA)表达量明显下调, 而膜通道蛋白glzT基因的表达显著上调, 说明广盐型聚球藻耐低盐机制主要是通过减少细胞内渗透压相关小分子合成和增加膜通道蛋白, 提高小分子物质外排来达到细胞内外渗透压平衡。此外, 盐度也会影响广盐型聚球藻的光合作用和代谢水平, 其中参与光合作用的产能基因(ATPF0BATPF0AATPF1DATPF1A)和色素蛋白基因(cpcA、cpcB)表达量在低盐条件下均显著下降, 同时无机氮利用相关基因表达上调。低盐条件下, 渗透压相关小分子的需求减少, 可以使更多的碳源用于支持生长, 同时无机氮的吸收增强, 这两者可能是低盐条件下广盐型聚球藻具有较高生长的原因。

关键词: 广盐型聚球藻, 转录组分析, 盐度

Abstract:

Synechococcus, which is one of the representative groups of picocyanobacteria, is widely distributed in global oceans and estuaries. It has high phenotypic (pigment) and genetic diversity. According to the level of ability to deal with variation in salinity, Synechococcus can be divided into the strictly marine type and euryhaline type. In this study, we compared the growth of Synechococcus sp. K1 (isolated from the Pearl River estuary) and Synechococcus sp. YX02-1 (isolated from the South China Sea oligotrophic water) under a series of salinity gradient conditions. We also conducted phylogenetic analysis of K1 and YX02-1 based on rpoC1 gene sequences. We found that euryhaline Synechococcus sp. K1 could grow in all salinity levels, while strictly marine Synechococcus sp. YX02-1 was unable to survive below 13‰, which is consistent with the distribution characteristics in the estuary. Transcriptome analysis showed that the expression of genes (ggpS, SPS, stpA) that synthesize osmotic pressure regulator molecules in euryhaline Synechococcus were significantly down-regulated, while the gene expression of the membrane channel protein glzT was significantly up-regulated under low-salinity condition. This suggests that the low-salt tolerance mechanism of euryhaline Synechococcus mainly includes reducing the synthesis of small molecules related to intracellular osmotic pressure and increasing membrane channel proteins to improve the efflux of small molecules. In addition, salinity affected the photosynthesis and metabolism levels of euryhaline Synechococcus. The expression of photosynthesis energy-saving genes (ATPF0B, ATPF0A, ATPF1D, ATPF1A) and pigment protein genes (cpcA, cpcB) were significantly down-regulated under low-salinity condition, and the expression of inorganic nitrogen utilization-related genes were up-regulated. Under low-salinity condition, the demand for small molecules related to osmotic pressure is reduced, which can make more carbon sources to support growth. Meanwhile, the absorption of inorganic nitrogen is enhanced. These two reasons may be responsible for the higher growth of Synechococcus under low-salinity condition.

Key words: Euryhaline Synechococcus, transcriptome analysis, salinity

中图分类号: 

  • P735.121