Characterization of Nicotiana tabacum plants expressing hybrid genes of cyanobacterial Δ9 or Δ12 acyl-lipid desaturases and thermostable lichenase

We established transgenic lines of Nicotiana tabacum expressing hybrid genes of Synechocystis sp. PCC 6803 Delta 12 (desA) acyllipid desaturase and Synechococcus vulcanus Delta 9 (desC) acyllipid desaturase with or without sequence coding for transit peptide of Rubisco small subunit of Arabidopsis thaliana under control of a constitutive promoter. Reliable increase of linoleic acid portion (C18:2; Delta 9,12) accompanied with decrease of alpha-linolenic acid (C18:3; Delta 9,12,15) relative amount was detected for plants expressing hybrid desA::licBM3 gene. No reliable changes were detected in fatty acid profiles and unsaturation index of plants transformed with Delta 9 desaturase gene desC::licBM3 lacking signals of intracellular targeting while expression of this gene with Arabidopsis thaliana Rubisco small subunit transit peptide sequence caused growth of C18:3 alpha-linolenic acid part simultaneously with reduction of C18:2 linoleic acid part, as well as increase of unsat-uration index. No changes in relative amount of Delta 9-monounsaturated fatty acids were observed in any of studied lines. All plants expressing desaturase genes exhibited enhanced levels of superoxide dismutase (SOD) activity after cold treatment in contrast to control lines with suppressed SOD activity after cold treatment.