Deschampsia Antarctica Dihydroflavonol-4-reductase Gene Improves Salt Adaptation in Tobacco

Deschampsia antarctica (DA) is a prominent vascular plant present in the Antarctic territory which has been able to tolerate extreme conditions for many years. In vitro experiments showed that DA efficiently responds to high salinity conditions (i.e. 300 mM NaCl), modulating gene expression and metabolites content involved in the phenylpropanoid pathway. In the present work, a full length DA cDNA, encoding the dihidroflavonol-4-reductase (DFR), was constitutively expressed in transgenic tobacco plant lines. A preliminary selection of candidate lines was carried out by qPCR, demonstrating the generation of several transgenic lines with differential DFR mRNA expression patterns. Additional evaluation of these positive lines revealed the generation of differential HPLC-MS metabolite profiles, with quercetin 3 hexoside and cyaniding 3 rutinoside as main overproduced metabolites, in comparison to wild type tobacco plants used as controls. A selected group of DFR positive lines, in which the transgene was found to be highly expressed, was evaluated for salt stress experiments. Challenges consisted of plantlets cultivation in MS solid media supplemented with 100 and 200 mM NaCl during three weeks. After this period, the results showed a relationship between highly-expressing DFR lines and the salt tolerant phenotype, suggesting that DA DFR is responsible for this phenotype in tobacco. This work is funded by the following Programs: INIA(Chile)-CSIC 501646-70, BIOFRUTALES Consortium, and FONDEF-CHILE G09I1008