TITLE	Antisense and RNAi expression for a chloroplastic superoxide dismutase gene in transgenic plants
AUTHOR	Shu-Yan CHEN School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China Sa XIAO School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China Man-Xiao ZHANG School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China Tuo CHEN School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China Hui-Chun WANG School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China Li-Zhe AN* School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China
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ABSTRACT	The cDNA of tomato chloroplastic Cu/Zn-superoxide dismutase was used to construct transgenic tobacco (Nicotiana plumbaginifolia). It was found that the gene expression of Cu/Zn-superoxide dismutase can constitutively be reduced in the transgenic tobacco plants because of double-stranded (dsRNA) expressed in the form of intron-spliced hairpin structures and antisense suppression. Furthermore, the endogenous chloroplastic Cu/Zn-superoxide dismutase gene in tobacco was established as a target for silencing due to the operation of hpRNA and antisense RNA constructs. However, under salt and PEG-induced stress, the cytosolic Cu/Zn-superoxide dismutase activity in transformed plants obviously increased. At the same time, the PEG pretreatment was able to promote tolerance of the transgenic plants to the salt stress. These results indicated that the use of hpRNA and anti-sense was able to successfully knockout the transcript encoding a chloroplast superoxidase dismutase. The null transformed plants grown under stress produced or retained other superoxide dismutase to compensate for the loss of the chloroplast. Consequently, hpRNA constructs would be helpful in discovering and validating the endogenous chloroplastic Cu/Zn-superoxide dismutase gene, and to prove the cytosolic alternative pathway of plant antioxidation associated with the function of Cu/Zn-superoxide dismutase gene under an unfavorable environment. Meanwhile, the experiment will provide an important technique for the antisensing strategies operating in tobacco.
KEYWORD	Double-stranded RNA; Salt stress; Superoxide dismutases; Transgenic tobacco;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 46 Number 3 July 2005, page 175-182, 8 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China