“Lotus hairy roots expressing ADC activity under stress induced promoter.”

CHIESA, MA. AMALIA, RUIZ, OSCAR. A. & SÁNCHEZ, DIEGO H

Barcelona, España

Congreso; 7th International Congress of Plant Molecular Biology; 2003

LOTUS HAIRY ROOTS EXPRESSING ADC ACTIVITY UNDER ATRESS INDUCED PROMOTER. María Amalia Chiesa, Oscar Adolfo Ruiz, diego Hernán Sánchez. IIB-INTECh (UNSAM-CONICET). Unidad de Biotecnología I. Chascomús, Pcia. De Buenos aires, Argentina. E-mail: ruiz@intech.gov.ar Lotus corniculatus is widely cultivated forage leguminose in Uruguay and Argentine. A very important feature of this plant is that is very amenable to genetic transformation and tissue culture. Moreover, it has been used as a model experimental plant for reproducible transformation studies in legumes. The hairy roots system is a technical alternative to traditional plant cell suspension. In addition, the hairy root system can be used as a continuous source for the production of valuable secondary metabolites. When the biotechnological approach includes the generation of transgenic plants, most reports relay on expression driven by constitutive CaMV 35S promoter. However, a more specific induction of the expression might be desirable when the gene encoding for a protein that affects growth or must be triggered in a specific time frame. In the present study we have brought together the L. cornuculatus hairy root tissue system properties ant the stress inducible promoter advantages to analyse the polyamines metabolic pathway. These polycations are ubiquitous among living organisms, and the arginine decarboxylase (ADC) is suspected to be rate-limiting step enzyme in plants under stress. Usually, their expression under constitutive promoter control, generate phenotype alterations suggesting that plant polyamines homeostasis is tightly regulated and more work is necessary to evaluate the regulation of the genes implicated. In order to investigate the potential roles of polyamines in a biotic stress in legumes, we develop a binary vector encoding the oat ADC and GUS sequences under control of RD29A promoter previously cloned from Arabidopsis. Transformed hairy roots of Lotus corniculatus have been produced using Agrobacterium rhizogenes and viable plants were obtained in free hormonal medium. These roots showed ADC and GUS activities induced by salt and /or cold. Also, the increase in the ADC activity was accompanied by a significant elevation in polyamines levels.