Virus-host coexistence in phytoplankton through the genomic lens

• DOI: 10.1126/sciadv.aay2587
• Publication Date: 2020-04-01T23:15:11Z
• Authors: Sheree Yau; Marc Krasovec; L. Felipe Benites; Stephane Rombauts; Mathieu Groussin; Emmelien Vancaester; Jean-Marc Aury; Evelyne Derelle; Yves Desdevises; Marie-Line Escande; Nigel Grimsley; Julie Guy; Hervé Moreau; Sophie Sanchez-Br...; Yves Van de Peer; Klaas Vandepoele; Sebastien Gourbiere; Gwenael Piganeau
• Keywords: Eukaryote

Virus-microbe interactions in the ocean are commonly described by "boom and bust" dynamics, whereby a numerically dominant microorganism is lysed replaced virus-resistant one. Here, we isolated microalga strain its infective dsDNA virus whose dynamics characterized instead parallel growth of both virus. Experimental evolution clonal lines revealed that this viral production originates from lysis minority virus-susceptible cells, which regenerated resistant cells. Whole-genome sequencing demonstrated resistant-susceptible switch involved large deletion on one chromosome. Mathematical modeling explained how maintains stable microalga-virus population consistent with their observed pattern. Comparative genomics confirmed an ancient origin "accordion" chromosome despite lack sequence conservation. Together, our results show dynamic genomic rearrangements may account for previously overlooked coexistence mechanism microalgae-virus interactions.