Pleiotropic mutants hypersensitive to heavy metals and to oxidative stressin Chlamydomonas reinhardtii

Insertional mutagenesis was used in Chlamydomonas reinhardtii to isolate or iginal mutants hypersensitive to multiple drugs and physical agents. Out of 5200 transformants analyzed, 13 mutants belonging to seven phenotypic clas ses were isolated. Five were exclusively sensitive to cadmium and represent ed two loci. The other mutants were pleiotropic and presented a cross sensi tivity to several (2-6) of the following agents: cadmium, copper, lead, par aquat, hydrogen peroxide, WC and light. In all mutants analyzed, the hypers ensitive phenotype was most probably due to a single mutational event. The sensitivity of several pleiotropic mutants to a broad range of physical and chemical agents suggests that the disrupted genes are involved in multiple stress responses. (C) 2001 Federation of European Microbiological Societie s. Published by Elsevier Science B.V. All rights reserved.