Definitely, giant viruses are everywhere! French researchers have announced that they have discovered three new giant pandoraviruses in different parts of the globe, including at the foot of an oak in the French city of Marseille.
This enabled them to conduct a comparative analysis of the genomes of the six pandoraviruses known until then and to advance a “revolutionary” hypothesis: these giant viruses, visible under an optical microscope, “invent their own genes”.
This bold deduction, published in the journal Nature Communications, should not fail to cause a debate, recognize the two microbiologists Chantal Abergel and Jean-Michel Claverie.
For several years now, this married couple has been hunting for giant viruses whose existence was first highlighted in 2003 with the discovery of the “Mimivirus”.
The two researchers work in the Genomics and Structural Information Laboratory (CNRS / Aix-Marseille University) in Marseille.
The pair discovered in 2013 the pandoravirus family, the largest known viruses. “We are only looking for viruses that can infect amoeba, their host cell, because it is safe for humans,” says Chantal Abergel, director of the laboratory. “We are obviously working in maximum security conditions”.
Pandoraviruses, one of four families known to be giant viruses, are as big as some bacteria. Amphora-shaped, they have a complex genome and they have about 1,500 to 2,000 genes.
The team described in Nature Communications three new members of the family, found in Marseille, in a mangrove near the airport of Nouméa (New Caledonia) and near Melbourne (Australia).
That of Marseille was discovered at the foot of an oak of a residence in the 9th district of the city. This earned him the name of Pandoravirus quercus (scientific name of this tree).
“Giant viruses are really everywhere on the planet, especially in the oceans, and they are really actors of the ecology,” says Chantal Abergel.