Feasibility of alternative selection methods for transgenic apple and pear using the detoxification gene Vr-ERE

International audienceEutypine is a toxin produced by Eutypa lata, the causal agent of eutypa dieback of grapevines. An eutypine detoxifying gene (Vr-ERE) encoding an NADPH-dependent aldehyde reductase converts eutypine into the corresponding alcohol, eutypinol, a non-toxic form of the toxin. A variety of phytotoxic compounds containing an aldehyde group can act as substrates for this enzyme, therefore opening the possibility to use Vr-ERE as an alternative selection system for plant transformation. Our preliminary experiments with apple and pear have demonstrated the following: 1) among the various substrates of VR-ERE, benzaldehyde (BD), a naturally occurring compound, is able to inhibit adventitious bud regeneration from apple as well as pear in vitro leaves, at concentrations ranging from 1 to 1.5 mM; 2) constitutive expression of Vr-ERE in transgenic ‘Greensleeves’ apple does not provoke any abnormal phenotype after one year of growth in greenhouse, but aldehyde reductase activity is reduced in all transgenic clones; 3) production of transgenic pear using BD instead of kanamycin as selection pressure is feasible, but the efficiency of the selection pressure seems low. In conclusion, the efficiency of Vr-ERE as a selective gene to produce apple and pear transgenic plants is not yet proven and further research is neede

Effect of ectopic expression of the eutypine detoxifying gene Vr-ERE in transgenic apple plants

UMR 1334 AGAP : Equipe AFEF ‘Architecture et Fonctionnement des Espèces fruitières’ ; Team AFFS ‘Architecture and Functioning of Fruit Species’ Contact: [email protected] Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceThe development of alternative selection systems without antibiotic resistance genes is a key issue to produce safer and more acceptable transgenic plants. Eutypine is a toxin produced by Eutypa lata, the causal agent of eutypa dieback of grapevine, which is detoxified in mung bean (Vigna radiata) by the gene Vr-ERE. Many phytotoxic compounds containing an aldehyde group can act as substrates for the Vr-ERE enzyme. The aim of the present work was to evaluate the effects of the overexpression of Vr-ERE in transgenic apple plants, as a first step towards the development of an alternative selection system. Viable transgenic apple clones expressing Vr-ERE were produced from the cultivar Greensleeves under kanamycin selection. Although the Vr-ERE transgene was normally expressed at the RNA and protein levels, the increase in aldehyde reductase activity tested on a range of potential substrates was very low in these clones. None of them revealed a significant increase in tolerance to toxic aldehydes compared to their non-transgenic control. This work with transgenic apple plants overexpressing the detoxifying gene Vr-ERE illustrates some of the difficulties in developing an alternative selection pressur