INVESTIGADORES
RUIZ oscar Adolfo
congresos y reuniones científicas
Título:
Physiological characterization of Lotus tenuis transgenic lines overspressing gene encoding arginine decarboxylase in response to high-salinity stress.
Autor/es:
ESPASANDÍN, F.D.; COLLAVINO M.M.; RUIZ O.A.; SANSBERRO P.A.
Lugar:
Montreal
Reunión:
Congreso; Plant Biology 2010; 2010
Resumen:
Lotus tenuis is an exotic forage legume scattered in the flooding Pampa of Argentina. Due to its high nutritive value and adaptive plasticity to the edaphic and environmental stresses, this species is considered an important alternative for cattle feed. To study how the steady-state content of free polyamines can be influenced by the stress-inducible overexpression of arginine decarboxylase, we constructed transgenic plants via Agrobacterium tumefaciens-mediated transformation. The binary vector used for transformation contained the RD29A osmotic stress-inducible promoter from Arabidopsis thaliana and the arginine decarboxylase gene from oat (pBiRD29:ADC), carried the selectable marker nptII gene. The RD29A:oat ADC Lt19 line and the wild type (wt) plants were analysed for ADC activity induced by osmotic treatment (200 mM NaCl) for 30 days. The Lt19 line showed a 73-fold increase in ADC activity compared with the untreated control of the same genotype, while the comparison with the stressed wt showed a 23-fold increase. We could not observe significant differences in decarboxylase activity between unstressed and stressed wt plants. The stressed Lt19 line accumulated almost two-fold more putrescine as compared with the unstressed samples. The transgenic line subjected to osmotic stress showed a higher photosynthetic rate with a WUE similar to stressed wt plants. Although, this physiological trait take place at expense of an additional stomatal conductance and transpiration rate, the water relations may be recovered with a great osmotic adjustment. Notwithstanding, the tolerance mechanism should be elucidated in the future.