罗氏沼虾育苗期浮游细菌群落演替模式、驱动因素及其生物标志物

THE DYNAMICS OF BACTERIOPLANKTON COMMUNITIES ASSOCIATED WITH MACROBRACHIUM ROSENBERGII ACROSS WHOLE LARVAL DEVELOPMENT: SUCCESSIONAL PROCESSES, ENVIRONMENTAL DRIVERS, AND DEVELOPMENTAL BIOMARKERS

  • 摘要: 为了探究罗氏沼虾(Macrobrachium rosenbergii)育苗期浮游细菌群落的时间动态和组装机制, 对3个苗种厂的全育苗周期进行持续追踪, 利用16S rRNA扩增子测序评估了罗氏沼虾幼苗发育过程中浮游细菌群落的动态演替、环境驱动因素、微生物标志物和共现网络。细菌群落的α-多样性在育苗期呈U型分布规律, 群落相似性遵循时间衰减模式, 群落周转率为0.011。随着虾苗的发育, 微杆菌科(Microbacteriaceae)(放线菌门: Actinobacteria)和冷形菌科(Cryomorphaceae)(拟杆菌门: Bacteroidetes)的相对丰度显著增加(P<0.05), 而拟杆菌门中的黄杆菌科(Flavobacteriaceae)和藏红花黄色线菌科(Crocinitomicaceae)的比重下降。pH是影响浮游细菌群落多样性和组成的最主要的环境驱动因素。利用随机森林分析, 鉴定了12个幼苗发育相关的微生物标志物, 其中伯克氏菌科(Burkholderiaceae)和圆杆菌科(Cyclobacteriaceae)分别是育苗早期(1—2d)和中期(8—10d)的指示性类群, 而腐螺旋菌科(Saprospiraceae)和分枝杆菌科(Mycobacteriaceae)作为标志物类群出现在中后期(16—21d)。育苗系统中菌群以正相关关系为主的共现模式随幼苗发育而减弱, 而负相互作用增加。研究结果揭示了罗氏沼虾育苗期浮游细菌群落的演替动态和群落聚集模式, 将为微生态调节和病害防控提供新见解。

     

    Abstract: A suitable micro-ecological condition is of great significance to the Macrobrachium rosenbergii larval development and health, however, the fine-scale temporal dynamics and assembly mechanisms of bacterioplankton of prawn larval nursery are unexplored. We investigated dynamic succession, environmental drivers, biomarkers and co-occurrence networks of bacterial communities across whole developmental cycle in 3 commercial prawn nurseries, using a high-frequency sampling strategy and bacterial 16S rRNA amplicon sequencing. The bacterial α-diversity showed a U-shaped pattern across the developmental cycle. The bacterial community’s similarity followed a time-decay pattern, with community turnover rate of 0.011. Bacteroidetes, Actinobacteria, Alphaproteobacteria, and Gammaproteobacteria were the dominant phyla, and their relative abundance varied dramatically with prawn larval development. For example, the relative abundance of actinobacterial Microbacteriaceae and Cryomorphaceae (Bacteroidetes) significantly increased with prawn larval development (P<0.05), while that of two members of phyla Bacteroidetes, Flavobacteriaceae and Crocinitomicaceae decreased. pH is the most important environmental driver for the variations of bacterial diversity and composition. By using random forest analysis, we identified 12 biomarker taxa associated with prawn larval development. Specifically, Burkholderiaceae and Cyclobacteriaceae as the indicative taxa were detected in early (1—2d) and median stage (8—10d), respectively. While Saprospiraceae and Mycobacteriaceae accumulated in mid-late stages (16—21d). Bacterial co-occurrence patterns (mostly positive correlations) weakened and negative interactions accumulated with larval development. These findings reveal notable succession patterns and community assembly dynamics of bacterioplankton across whole prawn larval development, and will provide novel insights into microbiome management practices and prevent disease in prawn nursery.

     

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