Baker Lydia J, Kemp Paul F
Microbiology, Cornell University, Ithaca, NY, United States of America.
Oceanography Department, University of Hawai'i Mānoa, Honolulu, HI, United States of America.
PeerJ. 2020 Jan 27;8:e8352. doi: 10.7717/peerj.8352. eCollection 2020.
Inoculation of axenic diatom monocultures with individual bacterial strains has been used effectively to examine the relationship between bacteria and a diatom host. Both beneficial and harmful effects on diatom fitness have been observed. Yet, diatoms commonly host a consortium of bacteria that could influence their response to perturbation by bacterial inoculations. In this study, diatom cultures with an existing microbiome were inoculated with individual bacterial strains. Strains of two genera of bacteria commonly found associated with diatoms ( and ) were isolated from a culture of the diatom s sp. KBDT20. To evaluate whether bacterial inoculations can impact the growth, peak abundance, or decline of diatoms with an intact microbiome, individual bacterial strains were inoculated into batch cultures of the original host as well as two non-origin diatom hosts ( sp. KBDT32 and sp. KBDT35). Inoculations were repeated under vitamin-replete and vitamin-deficient conditions to assess whether vitamin concentration modulates the impact of bacterial inoculations on the host. The origin culture was largely unperturbed by bacterial inoculations. In contrast, non-origin hosts experienced long-term impacts on their growth trajectory, and those impacts were found to be dependent on the concentration of vitamins in the growth medium. For the non-origin , all positive impacts were observed in vitamin-replete conditions and all negative impacts were observed in vitamin-deficient conditions. was only impacted by inoculation with strains in vitamin-deficient conditions, and the effect was negative. Neither individual bacterial strains nor genera resulted in exclusively beneficial nor detrimental impacts, and the magnitude of effect varied among bacterial strains. This study demonstrates that bacterial inoculations can have long-lasting impacts on the growth trajectory of diatoms with an existing microbiome, that this impact can differ even between congeneric diatoms, and that the impact can be significantly modulated by vitamin concentration.
用单个细菌菌株接种无菌硅藻单培养物已被有效地用于研究细菌与硅藻宿主之间的关系。已观察到对硅藻适应性既有有益影响也有有害影响。然而，硅藻通常携带一群细菌，这些细菌可能会影响它们对细菌接种干扰的反应。在本研究中，用单个细菌菌株接种具有现有微生物群的硅藻培养物。从硅藻sp. KBDT20的培养物中分离出通常与硅藻相关的两个细菌属（和）的菌株。为了评估细菌接种是否会影响具有完整微生物群的硅藻的生长、峰值丰度或衰退，将单个细菌菌株接种到原始宿主以及两个非原始硅藻宿主（sp. KBDT32和sp. KBDT35）的分批培养物中。在维生素充足和维生素缺乏的条件下重复接种，以评估维生素浓度是否调节细菌接种对宿主的影响。原始培养物在很大程度上未受到细菌接种的干扰。相比之下，非原始宿主的生长轨迹受到长期影响，并且发现这些影响取决于生长培养基中维生素的浓度。对于非原始的，在维生素充足的条件下观察到所有积极影响，在维生素缺乏的条件下观察到所有消极影响。仅在维生素缺乏的条件下接种菌株时受到影响，且影响是负面的。单个细菌菌株或属都不会只产生有益或有害影响，并且影响的程度在不同细菌菌株之间有所不同。本研究表明，细菌接种可对具有现有微生物群的硅藻的生长轨迹产生持久影响，这种影响甚至在同属硅藻之间也可能不同，并且这种影响可受到维生素浓度的显著调节。
