Table 1 Efficiency of different Agrobacterium-mediated transformation methods. Two different Agrobacterium strains (LBA4404 and C58C1), containing the pAgroR vector and two Chlamydomonas strains (CC125 and cw15) were used. Transformation efficiency is expressed as the number of colonies resistant to paromomycin/108 cells transformed. The presence of the Paro transgene was tested by PCR and is expressed as the percentage of Paro-resistant colonies testing positive in the PCR assay. Kanamycin (Kan)-positive transformants, indicative of bacterial contamination, were excluded from the analysis. Results of two independent experiments for each protocol/strain combination are reported. At least 50 independent transformants for each experiment were analyzed by PCR