Ecological traits of planktonic viruses and prokaryotes along a full-salinity gradient.
Virus-prokaryote interactions were investigated in four natural sites in Senegal (West Africa) covering a salinity gradient ranging from brackish (10‰) to near salt saturation (360‰). Both the viral and the prokaryote communities exhibited remarkable differences in their physiological, ecological and morphological traits along the gradient. Above 240‰ salinity, viral and prokaryotic abundance increased considerably with the emergence of (1) highly active square haloarchaea and of (2) viral particles with pleiomorphic morphologies (predominantly spindle, spherical and linear shaped). Viral life strategies also showed some salinity-driven dependence, switching from a prevalence of lytic to lysogenic modes of infection at the highest salinities. Interestingly, the fraction of lysogenized cells was positively correlated with the proportion of square cells. Overall, the extraordinary abundance of viruses in hypersaline systems (up to 6.8 × 10(8) virus-like particles per milliliter) appears to be partly explained by their high stability and specific ability to persist and proliferate in these apparently restrictive habitats.
IRD, UMR 5119 ECOSYM, Montpellier, France. yvan.bettarel@ird.fr
Yvan
Y
Bettarel
Thierry
T
Bouvier
Corinne
C
Bouvier
Claire
C
Carré
Anne
A
Desnues
Isabelle
I
Domaizon
Stéphan
S
Jacquet
Agnès
A
Robin
Télesphore
T
Sime-Ngando
D015169:Colony Count, Microbial; D017753:Ecosystem; D005843:Geography; D046529:Microscopy, Electron, Transmission; D010802:Phylogeny; D010933:Plankton / Q000254:growth & development / Q000821:virology*; D011387:Prokaryotic Cells / Q000382:microbiology* / Q000821:virology; D054712:Salinity; D012675:Senegal; D012965:Sodium Chloride; D014780:Viruses / Q000254:growth & development* / Q000302:isolation & purification / Q000648:ultrastructure; D014867:Water / Q000737:chemistry; D014871:Water Microbiology
D014867:Water; D012965:Sodium Chloride