Tobacco seeds simultaneously over-expressing Cu/Zn-superoxide dismutase and ascorbate peroxidase display enhanced seed longevity and germination rates under stress conditions.
Reactive oxygen species (ROS) are produced during seed desiccation, germination, and ageing, leading to cellular damage and seed deterioration and, therefore, decreased seed longevity. The effects of simultaneous over-expression of two antioxidant enzymes on seed longevity and seed germination under stressful conditions were investigated. Transgenic tobacco simultaneously over-expressing the Cu/Zn-superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) genes in plastids showed normal growth and seed development. Furthermore, the transgenic seeds displayed increased CuZnSOD and APX enzymatic activities during seed development and maintained antioxidant enzymatic activity after two years of dried storage at room temperature. The two-year stored non-transgenic seeds (aged NT seeds) had higher levels of ion leakage than the two-year stored transgenic seeds (aged CA seeds), indicating membrane damage caused by ROS was more severe in the aged NT seeds than the aged CA seeds. The aged CA seeds decreased germination rates as compared to newly harvested transgenic and non-transgenic seeds. The aged CA seeds, however, significantly increased germination rates under various abiotic stress conditions as compared to aged NT seeds. These data strongly suggest that simultaneous over-expression of the CuZnSOD and APX genes in plastids improves seed longevity and germination under various environmental stress conditions by attenuating the effects of oxidative stress produced by elongated storage conditions and harsh environmental stresses.
Lee
Young Pyo
YP
Plant Systems Engineering Research Center, KRIBB, 111 Gwarangno, Yuseong, Daejeon 305-806, Korea.
Baek
Kwang-Hyun
KH
Lee
Haeng-Soon
HS
Kwak
Sang-Soo
SS
Bang
Jae-Woog
JW
Kwon
Suk-Yoon
SY
D060387:Ascorbate Peroxidases; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D018525:Germination; D018384:Oxidative Stress; D010544:Peroxidases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D012639:Seeds / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*
D010940:Plant Proteins; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase