Publications (2)0 Total impact
Article: Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress.[show abstract] [hide abstract]
ABSTRACT: Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 22.214.171.124) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlated with the induction of known stress-responsive genes, and suggested that putrescine may be directly or indirectly involved in ABA metabolism and gene expression.Plant signaling & behavior 02/2011; 6(2):278-86.
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ABSTRACT: Polyamine metabolism has long been involved in plant stress responses, although physiological roles of putrescine, spermidine and spermine are still under debate. Regarding long-term salinization, it have been suggested that high titers of spermidine and/or spermine, but not putrescine, are correlated with the response of plants to salinity. In this work, we use the moderately salt tolerant glycophyte Lotus glaber as a model to test the hypothesis that free spermidine and spermine are biochemical indicators of salt stress response. For such purpose, we evaluated polyamine content in three different long-term salt stress approaches: germinating and growing seedlings under salinity, salinization of growing plants and imposition of salt stress to clone stem cuttings obtained from plants recovered from saline lowlands. Proline was also tested to evaluate if polyamines levels correlate with this compatible solute response. Results from these experiments showed a similar trend concerning higher polyamines content i.e., a salt induced a decrease of free spermidine and an increase of free spermine, in line with the idea that polyamine are biochemical indicators of salt stress. However, polyamine levels not always paralleled the accumulation of proline. These observations are discussed with regard of the putative roles reported for polyamines in plant abiotic stresses.Plant Science.