Deng Yunyan, Li Fengting, Shang Lixia, Hu Zhangxi, Yue Caixia, Tang Ying Zhong
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China.
Front Microbiol. 2024 Jul 22;15:1407459. doi: 10.3389/fmicb.2024.1407459. eCollection 2024.
Variation in the condition of marine sediments provides selective preservation milieus, which act as a key determinant for the abundance and distribution of dinoflagellate resting cysts in natural sediments. Microbial degradation is an understudied biological factor of potential importance in the processes. However, gaps remain in our knowledge about the fundamental information of the bacterial consortia associated with dinoflagellate resting cysts both in laboratory cultures and in the field. Here we used as a representative of cyst-producing dinoflagellates to delineate the diversity and composition of bacterial microbiomes co-existing with the laboratory-cultured resting cysts, and to explore possible impacts of low temperature, darkness, and anoxia (the mock conditions commonly observed in marine sediments) on the associated bacterial consortia. Bacterial microbiome with high diversity were revealed associated with at resting stage. The mock conditions could significantly shift bacterial community structure and exert notably inhibitory effects on growth-promoting bacteria. Resting cysts under conditions typically observed in marine sediments fostered bacterial microbiomes with more diverse trophic strategies, characteristic of prominently enriched anaerobic chemotrophic bacteria generating energy via respiration with several different terminal electron acceptors, which yielded more acidic milieu unfavorable for the preservation of calcareous resting cysts. Our findings suggest that there is complex and dynamic interaction between dinoflagellates resting cysts and the associated bacterial consortia in natural sediments. This intrinsic interaction may influence the maintenance and/or accumulation of dinoflagellate resting cysts with potential of germination and initiation blooms in the field.
海洋沉积物状况的变化提供了选择性保存环境，这是自然沉积物中鞭毛藻休眠孢囊丰度和分布的关键决定因素。微生物降解是该过程中一个潜在重要但研究不足的生物学因素。然而，我们对于实验室培养和野外环境中与鞭毛藻休眠孢囊相关的细菌群落的基本信息仍存在知识空白。在这里，我们以产孢囊鞭毛藻为代表，描绘与实验室培养的休眠孢囊共存的细菌微生物组的多样性和组成，并探讨低温、黑暗和缺氧（海洋沉积物中常见的模拟条件）对相关细菌群落的可能影响。研究发现，处于休眠阶段的鞭毛藻与具有高度多样性的细菌微生物组相关联。模拟条件可显著改变细菌群落结构，并对促生长细菌产生显著抑制作用。在海洋沉积物中通常观察到的条件下，休眠孢囊培育出具有更多样化营养策略的细菌微生物组，其特征是通过几种不同的末端电子受体进行呼吸作用产生能量的厌氧化学营养细菌显著富集，这产生了更酸性的环境，不利于钙质休眠孢囊的保存。我们的研究结果表明，在自然沉积物中，鞭毛藻休眠孢囊与相关细菌群落之间存在复杂而动态的相互作用。这种内在相互作用可能会影响鞭毛藻休眠孢囊的维持和/或积累，使其在野外具有萌发和引发水华的潜力。
