| Summary: | 碩士 === 國立成功大學 === 熱帶植物科學研究所 === 102 === Phalaenopsis is one of the high economic value of flower crops. As the beautiful floral morphology, diverse flower colour and long florescence duration are widely loved by people. A small family of Plant-specific TEOSINTE BRANCHED1, CYCLOIDEA, PCF (TCP) transcription factors encoding proteins sharing TCP domain with a bHLH motif that allows DNA binding and protein–protein interactions. According to slightly different TCP domains, TCP proteins are separated into two clades, including class I and class II. They are the main regulators of plant form and architecture and constitute a tool through which evolution shapes plant diversity. The TCP transcription factors act in a multiplicity of pathways related with cell proliferation and hormone responses. This study characterized the class I PCF and class II CIN gene subfamilies in the Phalaenopsis. We identified 20 genes belong to the PCF and CIN subfamilies in the OrchidBase. Phylogenetic analysis showed that 11 PCF genes and 9 CIN genes exist in the Phalaenopsis genome. RT-PCR results showed that 10 PCF genes and 8 CIN genes expressed in the vegetative tissue, reproductive tissue and developmental ovule stages. However, 1 PCF gene and 1 CIN gene were not detected by RT-PCR. Further, we characterized the function of the class I TCP transcription factor PePCF10 and the class II TCP transcription factor PeCIN8. Yeast-two hybrid assay results showed that strong interaction of PeCIN8 homodimers. However, PeCIN8 can not form heterodimer with PePCF10. In addition, PePCF10 could not form homodimers as well as heterodimers with PeCIN8. Subcellular localization experiments confirmed that both of two gene products localize in the nucleus. In transgenic Arabidopsis thaliana plants (overexpression and SRDX dominantly represses), the two genes display a range of growth-related phenotypes, consistent with their dynamic expression patterns. The two genes influence plant stature, flowering time, plant reproduction and morphogenesis of shoot lateral organs that via modulate cell division. Overall, our results show that PePCF10 and PeCIN8 transcription factors are a nuclear protein with a widely expression pattern and both of them appear to be playing an important role during plant development and provide some insights about the function of PeTCPs in the development of Phalaenopsis.
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