Overexpression of an Arabidopsis peroxisomal ascorbate peroxidase gene in tobacco increases protection against oxidative stress.
The Arabidopsis gene APX3 that encodes a putative peroxisomal membrane-bound ascorbate peroxidase was expressed in transgenic tobacco plants. APX3-expressing lines had substantial levels of APX3 mRNA and protein. The H2O2 can be converted to more reactive toxic molecules, e.g. .OH, if it is not quickly removed from plant cells. The expression of APX3 in tobacco could protect leaves from oxidative stress damage caused by aminotriazole which inhibits catalase activity that is found mainly in glyoxysomes and peroxisomes and leads to accumulation of H2O2 in those organelles. However, these plants did not show increased protection from oxidative damage caused by paraquat which leads to the production of reactive oxygen species in chloroplasts. Therefore, protection provided by the expression of APX3 seems to be specific against oxidative stress originated from peroxisomes, not from chloroplasts, which is consistent with the hypothesis that APX3 is a peroxisomal membrane-bound antioxidant enzyme.
Wang
J
J
Department of Biological Sciences, Texas Tech University, Lubbock 79409, USA.
Zhang
H
H
Allen
R D
RD
D000640:Amitrole / Q000494:pharmacology; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins; D060387:Ascorbate Peroxidases; D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D006540:Herbicides / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D008565:Membrane Proteins; D008830:Microbodies / Q000201:enzymology / Q000378:metabolism; D018384:Oxidative Stress; D010269:Paraquat / Q000494:pharmacology; D010544:Peroxidases / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D014170:Transformation, Genetic
D029681:Arabidopsis Proteins; D017931:DNA Primers; D006540:Herbicides; D008565:Membrane Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D006861:Hydrogen Peroxide; D010544:Peroxidases; C555294:APX3 protein, Arabidopsis; D060387:Ascorbate Peroxidases; D010269:Paraquat; D000640:Amitrole