Abstract
Phycospheric bacteria may be the key biological factors affecting the growth of algae. However, the studies about interaction between Isochrysis galbana and its phycospheric bacteria are limited. Here, we show that a marine heterotrophic bacterium, Alteromonas macleodii, enhanced the growth of I. galbana, and inhibited non-photochemical quenching (NPQ) and superoxide dismutase (SOD) activities of this microalgae. Further, we explored this phenomenon via examining how the entire transcriptomes of I. galbana changed when it was co-cultured with A. macleodii. Notable increase was observed in transcripts related to photosynthesis, carbon fixation, oxidative phosphorylation, ribosomal proteins, biosynthetic enzymes, and transport processes of I. galbana in the presence of A. macleodii, suggesting the introduction of the bacterium might have introduced increased production and transport of carbon compounds and other types of biomolecules. Besides, the transcriptome changed largely corresponded to reduced stress conditions for I. galbana, as inferred from the depletion of transcripts encoding DNA repair enzymes, superoxide dismutase (SOD) and other stress-response proteins. Taken together, the presence of A. macleodii mainly enhanced photosynthesis and biosynthesis of I. galbana and protected it from stress, especially oxidative stress. Transfer of fixed organic carbon, but perhaps other types of biomolecules, between the autotroph and the heterotroph might happen in I. galbana-A. macleodii co-culture. The present work provides novel insights into the transcriptional consequences of I. galbana of mutualism with its heterotrophic bacterial partner, and mutually beneficial associations existing in I. galbana-A. macleodii might be explored to improve productivity and sustainability of aquaculture algal rearing systems.
Highlights
How environmental factors affect the growth of microalgae is always a concern of researchers
As a step toward further understanding the underpinnings of the effects, we examined the transcriptional responses of I. galbana to grow in co-culture with A. macleodii
We have analyzed the growth by cell counting for co-cultures with three different initial bacteria/algae ratio of (1:1, 1:10, and 1:50) and I. galbana mono-culture (Figure 1)
Summary
How environmental factors affect the growth of microalgae is always a concern of researchers. Bacteria can release the growth-promoting hormone indole-3-acetic acid (Amin et al, 2015; Dao et al, 2018), provide essential vitamins to algae (Croft et al, 2005; Cooper et al, 2019), scavenge reactive oxygen species (ROS) (Morris et al, 2008, 2011), promote algal assimilation of iron (Amin et al, 2009, 2012a), or metabolically transform compounds released by autotrophs in ways that can impact the entire community (Durham et al, 2015; ChristieOleza et al, 2017) Such studies have begun to investigate which factors drive algal-bacterial interactions, yet there are many gaps in our understanding of these processes. Mutually beneficial associations existing between I. galbana and A. macleodii might be explored to improve productivity and sustainability of aquaculture algal rearing systems
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
