Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 3.20

CD TOLERANCE OF NICOTIANA TABACUM ROLB-TRANSFORMED ROOTS IS ENHANCED BY OVEREXPRESSING PHYTOCHELATIN SYNTHASE

CENSI V.*, POMPONI M.*, DE PAOLIS A.**, COSTANTINO P.*, CARDARELLI M.***

*) Dip. Genetica e Biologia molecolare, UNI ‘La Sapienza’ Roma, Italy

**) Ist. Orticoltura e Coltura Industriale, CNR Tito Scalo (Pz) Italy

***) Centro Acidi Nucleici c/o Dip. Genetica e Biologia molecolare, UNI ‘La Sapienza’ Roma, Italy

phytochelatins, Cd tolerance, rolB, glutathione

It has been demonstrated that phytochelatins (PCs) play a key role in metal tolerance since many plants overproduce phytochelatins when exposed to excess heavy metals and phytochelatin synthase gene increases metal tolerance in yeast. Our approach is to overexpress the Arabidopsis PC synthase gene in tobacco, both wild-type and transformed with the rolB gene of Agrobacterium rhizogenes, and evaluate transgenic plants for cadmium tolerance. rolB-expressing plants are a good experimental system because rolB induce an expansion of the root system in tobacco plants. On the other hand rolB and normal tobacco plants show no differences in their resistance to different Cd concentrations. Normal and rolB tobacco plants have been transformed with a construct containing the coding region of PC synthase from Arabidopsis driven by the CaMV35S promoter (construct PCS1). To test Cd tolerance, we compared the ‘in vitro’ growth rate of PCS1-rolB and rolB roots in the presence of different Cd concentrations. Our results suggest that overexpression of AtPCS1 in tobacco plants increases Cd tolerance of rolB roots.. Furthermore this effect is enhanced by addition of glutathione (GSH), PC synthase substrate, to the root culture medium.