| Summary: | 碩士 === 國立屏東科技大學 === 熱帶農業暨國際合作研究所 === 92 === Tissue culture has been widely used for mass propagation of Phalaenopsis, however, the occurrence of somaclonal variation during micropropagation process is a severe problem affecting product quality. Normal and peloric flower buds of Phalaenopsis were used for cDNA-RAPD and cDNA subtraction analysis to study their differences in terms of expressed genes. A total of 209 ESTs from normal flower buds and 230 from mutants were sequenced and found to belong to several gene categories with different functions, including the most unknown proteins, orchid virus and related genes on metabolism, signal transduction, transcription, cell growth and division, protein synthesis, and protein destination. Several selected cDNA clones were analyzed for their preferential expression using real-time PCR. The result showed that bZIP transcription factor is down-regulated in mutant flower, while APK1 protein kinase, cyclophilin, and TCP-like genes are up-regulated, which probably present the effects from the changing of signal transduction and transcription. A retroelement clone was preferentially expressed in mutants. Some other ESTs involving DNA methylation, chromatin remodeling and post-transcriptional regulation were selectively expressed in normal flower buds, such as DNA methyltransferase, histone acetyltransferase, ERECTA, and DEAD/DEAH RNA helicase, indicating their probable roles in growth and development of Phalaenopsis flower buds.
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