Expression and Analysis of an Orchid (Oncidium Gower Ramsey) Lipid Acyl Hydrolase-like Gene in Arabidopsis thaliana
Date Issued
2006
Date
2006
Author(s)
Chu, Chung-Fu
DOI
zh-TW
Abstract
In Taiwan, Oncidium Gower Ramsey is the most potential cutting flower of Orchid exported to Japan at present. However, the transportation takes too much time and seriously damaged the qualities of those cutting flowers. Therefore, how to repress the senescence of the cutting flower of Oncidium has become an essential topic of study. OSAG78 is a senescence-induced gene and expressed throughout the whole plant, and OSAG78, perhaps, is a lipid acyl hydrolase based on the NCBI database. We isolated the full-length cDNA of OSAG78 by using RACE (Rapid Amplification of cDNA Ends), and the ectopic expressions of OSAG78, driven by AGL5 promoter and 35S promoter respectively, in Arabidopsis were analyzed. Compared with wild-type plant, Arabidopsis transformed with 35S::OSAG78 displayed higher lipid acyl hydrolase activity, and also it showed the more circular and smaller flowers and leaves, the smaller surface area of cells, the smoother cell shape, and the relatively smaller plants. Moreover, the 35S::OSAG78 Arabidopsis delayed flowering and postponed senescence of leaves and flowers. However, the AGL5::OSAG78 Arabidopsis displayed the same specific phenotypes in flowers only. These results suggest that these specific phenotypes result from the rising of the acyl hydrolase activity that excessively decomposed the phospholipids in the cell membrane. Moreover, the postponement of flowering in transgenic Arabidopsis can be restores by the treatment of gibberelin (GA), indicating that overexpression of OSAG78 in plant may interfere in the regulation of GA which regulate flowering. Conclusively, OSAG78 shows acyl hydrolase activity, and the overexpression of OSAG78 in plant may produce lysophospholipid which inhibits the function of phospholipid D and then delays the senescence of leaves and postpones the time of flowering. In the future, we hope to overexpress OSAG78 in Oncidium to delay the senescence of Oncidium cutting flower.
Subjects
老化
lipid acyl hydrolase
sensecence
Type
other
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