Enhanced tolerance to sulfur dioxide and salt stress of transgenic Chinese cabbage plants expressing both superoxide dismutase and catalase in chloroplasts.
To explore the possibility of overcoming the highly phytotoxic effect of SO(2) and salt stress, we introduced the maize Cu/ZnSOD and/or CAT genes into chloroplasts of Chinese cabbage (Brassica campestris L. ssp. pekinensis cv. Tropical Pride) (referred to as SOD, CAT and SOD+CAT plants). SOD+CAT plants showed enhanced tolerance to 400 ppb SO(2), and visible damage was one-sixth that of wild-type (CK) plants. In addition, when SOD+CAT plants were exposed to a high salt treatment of 200 mM NaCl for 4 weeks, the photosynthetic activity of the plants decreased by only 6%, whereas that of CK plants decreased by 72%. SOD plants had higher total APX and GR activities than CK plants. As expected, SOD plants showed levels of protection from SO(2) and salt stress that were moderately improved compared to CK plants. However, CAT plants showed inhibition of APX activity and provided only limited improvements in plant stress tolerance. Moreover, SOD+CAT plants accumulated more K(+), Ca(2+) and Mg(2+) and less Na(+) in their leaves compared with those of CK plants. These results suggest that the expression of SOD and CAT simultaneously is suitable for the introduction of increased multiple stress protection.
Tseng
Menq Jiau
MJ
Department of Horticulture, National Chung Hsing University, Taichung 402, Taiwan, ROC.
Liu
Cheng-Wei
CW
Yiu
Jinn-Chin
JC
D015152:Blotting, Northern; D001937:Brassica / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D002374:Catalase / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects / Q000235:genetics; D010788:Photosynthesis / Q000187:drug effects; D030821:Plants, Genetically Modified; D011188:Potassium / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013458:Sulfur Dioxide / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D003313:Zea mays / Q000201:enzymology / Q000235:genetics
D013458:Sulfur Dioxide; D012965:Sodium Chloride; D012964:Sodium; D002374:Catalase; D013482:Superoxide Dismutase; D011188:Potassium