Low Host Abundance and High Temperature Determine Switching from Lytic to Lysogenic Cycles in Planktonic Microbial Communities in a Tropical Sea (Red Sea)
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
Marine Science Program
Red Sea Research Center (RSRC)
Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
KAUST Grant NumberBAS/1/1072-01-01
Permanent link to this recordhttp://hdl.handle.net/10754/664240
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AbstractThe lytic and lysogenic life cycles of marine phages are influenced by environmental conditions such as solar radiation, temperature, and host abundance. Temperature can regulate phage infection, but its role is difficult to discern in oligotrophic waters where there is typically low host abundance and high temperatures. Here, we study the temporal variability of viral dynamics and the occurrence of lysogeny using mitomycin C in a eutrophic coastal lagoon in the oligotrophic Red Sea, which showed strong seasonality in terms of temperature (22.1–33.3 °C) and large phytoplankton blooms. Viral abundances ranged from 2.2 × 106 to 1.5 × 107 viruses mL−1 and were closely related to chlorophyll a (chl a) concentration. Observed high virus-to-bacterium ratio (VBR) (4–79; 16 ± 4 (SE)) suggests that phages exerted a tight control of their hosts as indicated by the significant decrease in bacterial abundance with increasing virus concentration. Heterotrophic bacterial abundance also showed a significant decrease with increasing temperature. However, viral abundance was not related to temperature changes and the interaction of water temperature, suggesting an indirect effect of temperature on decreased host abundance, which was observed at the end of the summertime. From the estimated burst size (BS), we observed lysogeny (undetectable to 29.1%) at low percentages of 5.0% ± 1.2 (SE) in half of the incubations with mitomycin C, while it increased to 23.9% ± 2.8 (SE) when the host abundance decreased. The results suggest that lytic phages predominate, switching to a moderate proportion of temperate phages when the host abundance reduces.
CitationAbdulrahman Ashy, R., & Agustí, S. (2020). Low Host Abundance and High Temperature Determine Switching from Lytic to Lysogenic Cycles in Planktonic Microbial Communities in a Tropical Sea (Red Sea). Viruses, 12(7), 761. doi:10.3390/v12070761
SponsorsWe are particularly grateful to Curtis Suttle for his advice. We would like to thank Ayala, J.M., and Gonzalez, G. for their laboratory assistance and fieldwork during the samplings. We also thank and appreciate Prabowo, D. for his technical support during our research.
This research was funded by King Abdullah University of Science and Technology (KAUST) through center competitive fund (CCF) and baseline research funds (BAS/1/1072-01-01) to S.A.
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