Halophilic archaea use a fusion-based mating system for lateral gene transfer across cells. This cell fusion process is thought to be unique to archaea among the prokaryotes, and has yet to be observed outside the haloarchaea. Previous work has shown that cell fusion relies on some cell-cell recognition aspects, since fusion occurs more efficiently between cells from the same species. However, what factors on the cell surface need to be recognized for mating to take place and whether environmental factors play a role remains unknown. Here we present data showing the positive influence of higher salt concentrations on the formation of mating products, recombinant hetero-diploid cells in the halophilic species Hfx. volcanii. By combining salinity experiments and glycosylation mutant analysis we show that mating is a dominant trait and that is affected by surface protein glycosylation.
