ABSTRACT
In order to investigate the high temperature tolerance of spring canola plants (Brassica napus L.) constitutively expressing cyp11A1 gene which encodes bovine cytochrome P450(scc) the growth features were analyzed under short time heat stress (42 degrees C) in growth chamber. Earlier it was documented that results of the heat tolerance test positively correlated with improvement of high temperature resistance in field trial. Higher relative water content (by 13%) and superoxide dismutase (SOD) activity, lower electrolyte leakage (up 1.4-fold) and smaller increase in chlorophyll a and carotenoid contents in cyp11A1 canola leaves in comparison with wild-type plants under stress allowed to conclude cyp11A1 plants are more tolerant to high temperature than the control ones. We suppose that SOD activity increase which revealed in our transgenic canola in normal condition plays the defining role in the biochemical alterations in plant metabolism for the thermotolerance improvement. SOD activity increment could be caused by heterologous cytochrome P450(scc) activity which resulted in the superoxide radical formation. Cyp11A1 canola plants might be resistant to the other stress conditions of different origin.
Subject(s)
Brassica napus/enzymology , Cholesterol Side-Chain Cleavage Enzyme/metabolism , Hot Temperature , Plants, Genetically Modified/enzymology , Stress, Physiological , Animals , Antioxidants/metabolism , Brassica napus/genetics , Brassica napus/growth & development , Cattle , Cholesterol Side-Chain Cleavage Enzyme/genetics , Photosynthesis/physiology , Pigments, Biological/metabolism , Plant Leaves/enzymology , Plant Leaves/genetics , Plant Leaves/growth & development , Plants, Genetically Modified/growth & development , Stress, Physiological/geneticsABSTRACT
Superoxide dismutase (SOD) activity was investigated in leaves of transgenic canola plants which expressed heterologous genes of different origin, namely 1) herbicide resistance genes (bar and simultaneously bar and epsps); 2) DesC desaturase gene (desC) of cyanobacterium Synechococcus vulcanus; 3) human interferon alpha2b gene (huLFN-alpha2b); 4) esxA::fbpB(deltaTMD) fused gene, encoding ESAT-6 and Ag85b Mycobacterium tuberculosis proteins, inducing immune response against tuberculosis; 5) cyp11A1 gene of cytochrome P450(scc) from bovine adrenal cortex mitochondria. Introduction of herbicide resistance genes as well as desaturase gene of cyanobacterium and mycobacterium's genes did not change leaf SOD activity. At the same time it was shown that cyp11A1 and huIFN-alpha2b canola have increased leaf SOD activity up 58 and 33%, respectively, compared with control ones in non-stress conditions. It may be a prerequisite for improved resistance of these plants to the stressors of different origin.
