Osmoregulation in Chlamydomonas reinhardtii: Isolation and characterization of mutants obtained by insertional mutagenesis

Karin Komsic-Buchmann, and Burkhard Becker

Botanical Institute, Univeristy of Cologne, Cologne, Germany

Chlamydomonas cells contain two contractile vacuoles (CV) involved in osmoregulation. We have isolated osmoregulatory mutants using an insertional mutagenesis approach. Chlamydomonas CC-3395 (cwd,arg7-8) was transformed with a 1.7 kB DNA fragment containing the hygromycin resistence gene (aph7 gene). 2585 hygromycin-resistent clones were obtained and screened for failure or slow growth in hypotonic media. Several putative osmoregulatory mutants were isolated. Preliminary microscopic observations indicate that at least in some mutants the insertion apparently interferes with CV function. We will present a characterization of several osmoregulatory mutants.

e-mail address of presenting author: karin.buchmann@gmx.de