CONICET | Buscador de Institutos y Recursos Humanos

Salt stress negatively affects plants due to osmotic effects, ion toxicity and nutritional disorders. One of the strategies to protect from this stress is to avoid ion toxicity by compartmentalization of Na+ in vacuoles mediating by Na+/H+ antiporters of the NHX type located in the tonoplast. To study the importance of NHX1 antiporter of L. tenuis (LtNHX1) in plant salt tolerance, by mean of Agrobacterium tumefaciens-mediated transformation, we obtained L. tenuis plants overexpressing or silencing LtNHX1. The first binary vector contained the LtNHX1 coding region under the control of CaMV35S constitutive promoter (35S:NHX1), while the other vector contained an inverted repeat of a 272-bp fragment of LtNHX1, to trigger post-transcriptional gene silencing under the control of the CaMV35S promoter (35S:PTGS). Both vectors carry the bialaphos acetyltransferase gene (bar), which confers resistance to glufosinate-ammonium. After 90 days of culture on selection medium, 36% of the leaf explants inoculated with Agrobacterium harbouring 35s:NHX1 regenerated, forming 3 or 4 adventitious buds/explants, without callus formation. Thus, we obtained three transgenic lines. Moreover, 54% of the explants inoculated with Agrobacterium harbouring 35S:PTGS produced 1.5±0.5 adventitious buds per responsive explant resulting in two transgenic lines. Consequently, we consigned a transformation efficiency of 3.75% and 2.75%, respectively. In all cases, the transformation was confirmed by PCR. Finally, the transgenic shoots were transferred to a fresh MS medium without growth regulators for elongation and rooting to evaluate the biochemical and physiological responses of the plantlets to salt stress.