Poster: Biotech risk assessment

Abs # 922: The gene dihydrodipicolinate synthase r1: an alternative selectable marker gene for transgenic potato plants under amino ethyl cystein (AEC) selection

Presenter:	Yactayo, Jessica , jyactayo@cgiar.org
Authors	Yactayo, Jessica  (A)   Perazzo, Giovana  (A)   Condori, José  (A)   Ñopo, Luis  (A)   Jacobs, Michel  (B)   Frankard, Valerie  (B)   Ghislain, Marc  (A)
Affiliations:	(A): International Potato Center (B): Vrije Universiteit Brussel

A tobacco gene responsible for the synthesis of the essential amino acid lysine was introduced by agro-infection into potato variety Désirée and to confer resistance to a toxic lysine analog S-(amino ethyl)-L-cysteine (AEC). This finding let us to test this gene as a selectable marker for plant transformation in order to replace the antibiotic resistance genes that are a source of concern for consumer associations. Two system to increase efficiency, a liquid media (using temporary immersion system-RITA®) and semi-solid media (petri dishes) were tested. Co-culture media was done with 5x107 bacteria/ml in 4.6 g/l Murashige & Skoog (MS) salts and 20 g/l sucrose, at 22°C for 48 hours in the dark. Shoot regeneration was achieved on a medium comprising 4.6 g/l MS salts, 20 g/l sucrose, 5 g/l agarose, 0.02 mg/l gibberelic acid, 0.02 mg/l naphthalene acetic, 2 mg/l zeatine and 200 mg/l cefotoxine, plus either AEC at concentration from 50 to 200 µM. By using delayed selection after either two or four-weeks recovering period following plant transformation, we successfully selected thirty-one transformation events based on PCR test, although at low efficiency. The efficiency of the selection is now the focus the research work for which new gene constructs have been prepared.