[Promoter specificity of LE-ACS6 gene in LE-ACS6::GUS transgenic arabidopsis plants].
The LE-ACS6 gene encodes ACC synthase, the key enzyme of ethylene biosynthesis pathway. Accumulation of LE-ACS6 transcripts is concomitant with the system 1 ethylene production in the pre-climacteric tomato fruit, and both are down regulated by exogenous ethylene treatment. To elucidate the possible role of system 1 ethylene in plant development and investigate the promoter tissue specificity of LE-ACS6 gene, stable transformation of Arabidopsis with a LE-ACS6 promoter-GUS fusion construct by Agrobacterium method has been done. Histochemical localization of GUS activity and beta-glucuronidase enzyme assay in transgenic LE-ACS6::GUS plants showed strong expression of GUS in cotyledons and hypocotyls of 6 d seedlings, but no GUS activity was detected in roots. The GUS activity of 6 d seedling was increased significantly when treated with NAA 10(-4)mol/L. In 40 d rosette leaf LE-ACS6 promoter driven GUS gene was predominantly expressed in mature leaves. Lower level of GUS expression was detected in younger and older leaves. Wounding was found to increase GUS gene expression in transgenic leaves. Again, exogenous NAA was found to increase the GUS activity in wounded leaf tissue. Strong staining reaction was observed in the top part of rapidly growing stems. In different developmental stages of Arabidopsis seeds, "mature green" pods were strongly stained, but "ripening fruits" were not colored. These observations are concomitant with the system 1 ethylene production, suggesting a popular mechanism in regulating ethylene biosynthesis in different plants, at least in tomato and Arabidopsis.
Fan
Rong
R
Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
Wan
Xiao-Rong
XR
Zhang
Wen-Tao
WT
Wang
Shu-Fang
SF
Wang
Yong
Y
Zhu
Liang-Ji
LJ
Wang
Ning-Ning
NN
Shih
Ming-Che
MC
Charng
Yee-Yung
YY
Yang
Shang Fa
SF
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D005030:Ethylenes / Q000378:metabolism*; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
D005030:Ethylenes; C036216:ethylene; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase