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Pseudo-nitzschia Challenged with Co-occurring Viral Communities Display Diverse Infection Phenotypes.

Carlson MC, McCary ND, Leach TS, Rocap G - Front Microbiol (2016)

Bottom Line: Diatom-virus dynamics were explored by sampling every month at two coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples.Isolates that were infected by the most viral communities also had the highest maximum observed viral titers (as high as 16000 infectious units ml(-1)).The interactions between Pseudo-nitzschia and the viral communities highlight the diversity of diatoms and emphasize the complexity and variability of diatom-virus dynamics in the ocean.

View Article: PubMed Central - PubMed

Affiliation: School of Oceanography, University of Washington Seattle, WA, USA.

ABSTRACT
Viruses are catalysts of biogeochemical cycling, architects of microbial community structure, and terminators of phytoplankton blooms. Viral lysis of diatoms, a key group of eukaryotic phytoplankton, has the potential to impact carbon export and marine food webs. However, the impact of viruses on diatom abundance and community composition is unknown. Diatom-virus dynamics were explored by sampling every month at two coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples. We conducted a total of 820 pair-wise crosses of the Pseudo-nitzschia isolates and viral communities. Viral communities infected Pseudo-nitzschia isolates in 8% of the crosses overall and 16% of crosses when the host and viral communities were isolated from the same sample. Isolates ranged in their permissivity to infection with some isolates not infected by any viral samples and others infected by up to 10 viral communities. Isolates that were infected by the most viral communities also had the highest maximum observed viral titers (as high as 16000 infectious units ml(-1)). Titers of the viral communities were host dependent, as titers for one viral sample on eight different hosts spanned four orders of magnitude. Sequencing of the Pseudo-nitzschia Internal Transcribed Spacer 1 (ITS1) of the revealed multiple subgroups of hosts with 100% ITS1 identities that were infected by different viral communities. Indeed, we repeatedly isolated groups of isolates with identical ITS1 sequences from the same water sample that displayed different viral infection phenotypes. The interactions between Pseudo-nitzschia and the viral communities highlight the diversity of diatoms and emphasize the complexity and variability of diatom-virus dynamics in the ocean.

No MeSH data available.


Related in: MedlinePlus

Pseudo-nitzschia – virus infection network. Filled boxes represent infectious crosses. Black outlines delineate groups of hosts that share identical ITS1 sequences, which are labeled underneath.
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Figure 6: Pseudo-nitzschia – virus infection network. Filled boxes represent infectious crosses. Black outlines delineate groups of hosts that share identical ITS1 sequences, which are labeled underneath.

Mentions: The Pseudo-nitzschia hosts were grouped by ITS1 based species identification and ITS1 percent sequence identity, and ordered within each group according to the number of infectious crosses with the viral communities (Figure 6). Five groups of isolates had 100% nucleotide identity at the ITS1 region (Figure 6). Sixteen P. pungens strains with 100% identical ITS1 sequences consisted of 12 infection phenotypes, defined as the pattern of infection resulting from crosses with the viral communities. A second group of 8 P. pungens strains with a different ITS1 sequence consisted of six infection phenotypes. The phenotypes ranged from infected by multiple viral communities to not infect at all. This same pattern of diverse infection phenotypes within groups of isolates with 100% identical ITS1 sequences was observed in P. multiseries (three infection phenotypes in four strains), P. australis (two infection phenotypes in three strains), and P. delicatissima (two infection phenotypes in two strains) (Figure 6). In fact, of the 28 strains that were infected by at least 1 viral community, only two strains, P. pungens GH 14 and P. americana GH39, displayed the same infection phenotype, and they belonged to different species.


Pseudo-nitzschia Challenged with Co-occurring Viral Communities Display Diverse Infection Phenotypes.

Carlson MC, McCary ND, Leach TS, Rocap G - Front Microbiol (2016)

Pseudo-nitzschia – virus infection network. Filled boxes represent infectious crosses. Black outlines delineate groups of hosts that share identical ITS1 sequences, which are labeled underneath.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837327&req=5

Figure 6: Pseudo-nitzschia – virus infection network. Filled boxes represent infectious crosses. Black outlines delineate groups of hosts that share identical ITS1 sequences, which are labeled underneath.
Mentions: The Pseudo-nitzschia hosts were grouped by ITS1 based species identification and ITS1 percent sequence identity, and ordered within each group according to the number of infectious crosses with the viral communities (Figure 6). Five groups of isolates had 100% nucleotide identity at the ITS1 region (Figure 6). Sixteen P. pungens strains with 100% identical ITS1 sequences consisted of 12 infection phenotypes, defined as the pattern of infection resulting from crosses with the viral communities. A second group of 8 P. pungens strains with a different ITS1 sequence consisted of six infection phenotypes. The phenotypes ranged from infected by multiple viral communities to not infect at all. This same pattern of diverse infection phenotypes within groups of isolates with 100% identical ITS1 sequences was observed in P. multiseries (three infection phenotypes in four strains), P. australis (two infection phenotypes in three strains), and P. delicatissima (two infection phenotypes in two strains) (Figure 6). In fact, of the 28 strains that were infected by at least 1 viral community, only two strains, P. pungens GH 14 and P. americana GH39, displayed the same infection phenotype, and they belonged to different species.

Bottom Line: Diatom-virus dynamics were explored by sampling every month at two coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples.Isolates that were infected by the most viral communities also had the highest maximum observed viral titers (as high as 16000 infectious units ml(-1)).The interactions between Pseudo-nitzschia and the viral communities highlight the diversity of diatoms and emphasize the complexity and variability of diatom-virus dynamics in the ocean.

View Article: PubMed Central - PubMed

Affiliation: School of Oceanography, University of Washington Seattle, WA, USA.

ABSTRACT
Viruses are catalysts of biogeochemical cycling, architects of microbial community structure, and terminators of phytoplankton blooms. Viral lysis of diatoms, a key group of eukaryotic phytoplankton, has the potential to impact carbon export and marine food webs. However, the impact of viruses on diatom abundance and community composition is unknown. Diatom-virus dynamics were explored by sampling every month at two coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples. We conducted a total of 820 pair-wise crosses of the Pseudo-nitzschia isolates and viral communities. Viral communities infected Pseudo-nitzschia isolates in 8% of the crosses overall and 16% of crosses when the host and viral communities were isolated from the same sample. Isolates ranged in their permissivity to infection with some isolates not infected by any viral samples and others infected by up to 10 viral communities. Isolates that were infected by the most viral communities also had the highest maximum observed viral titers (as high as 16000 infectious units ml(-1)). Titers of the viral communities were host dependent, as titers for one viral sample on eight different hosts spanned four orders of magnitude. Sequencing of the Pseudo-nitzschia Internal Transcribed Spacer 1 (ITS1) of the revealed multiple subgroups of hosts with 100% ITS1 identities that were infected by different viral communities. Indeed, we repeatedly isolated groups of isolates with identical ITS1 sequences from the same water sample that displayed different viral infection phenotypes. The interactions between Pseudo-nitzschia and the viral communities highlight the diversity of diatoms and emphasize the complexity and variability of diatom-virus dynamics in the ocean.

No MeSH data available.


Related in: MedlinePlus