?EMS MUTAGENISED POPULATION OF EUTREMA SALSUGINEUM: A ?NEW TOOL TO DISCOVER MECHANISMS OF TOLERANCE TO ?EXTREME ENVIRONMEN

The similarity to of its genetic make-up, morphology and development together with the recent release of the genome sequence make it an ideal species to study mechanisms of tolerance to extreme environments. To generate a mutagenized population for both forward and reverse genetic studies in E. salsugineum, we optimized the EMS (Ethyl Methanesulfonate) treatment procedure for this species. We used the ver162 mutant, developed in the laboratories of Dr. Jian-Kang Zhu, which does not require vernalization in order to flower and is therefore more suitable for our studies. Different concentrations of EMS in the treatment were tested on 50 mg of seeds and the impact of the mutagenesis measured by the adverse effect on seed germination and the presence of albino sections on leaves. Based on these parameters, we have identified a method for mutagenizing E. salsugineum on a scale and efficiency comparable to A. thaliana. A final concentration of 0.6% EMS for 6 hours, which caused the desidered 40% reduction in seed germination was thus deemed optimal and used to perform bulk-mutagenesis. After 2 weeks of stratification, mutagenised seeds were germinated and transferred to soil to collect the M-2 generation in pools. As an indication of the success of the mutagenesis, we obtained 12 M-1 plants requiring vernalization, indicating a possible reverting phenotype compared to background ver162. M-2 seeds will be used to carry out large-scale screenings in order to identify genes and mechanisms important for salt, cold and drought tolerance in halophytes plants.