Summary: | 碩士 === 國立屏東科技大學 === 生物科技系所 === 101 === Phalaenopsis aphrodite subsp. formosana, one of important parent on Phalaenopsis breeding.There is a variegated mutant of the species can be found. In this study, we will examine to reveal the mechanism of gene regulation for the variegated mutant. The cross section of the variegated leaf was conducted by confocal laser-scanning microscopy and transmission electron microscope. The cells of green sectors contain normal chloroplasts, cells in the yellow sectors contain plastids that lack pigments and thylakoid. In proteomic analysis, four differential expression proteins between the green and yellow sectors of leaves can be identified as CPHSP 70-1, coat protein of CymMV, PsbP and PsbO by two-dimensional electrophoresis and LC/MS/MS. The semi-quantitative reverse transcriptase PCR and real-time PCR were used to amplify cDNA products reverse transcribed from mRNA and compare express between PsbO and PsbP and full-length cDNA of the genes mentioned above were cloned by the method of RACE technology. A full-length cDNA of PsbO and PsbP were cloned by RACE analysis and we fund that both PsbO and PsbP have the variant transcripts caused by intron retention. The total expression of both functional and variant transcripts from PsbO and PsbP between green and yellow sectors showed no difference by real-time PCR. Moreover, the expression of CymMV coat protein in yellow sector is higher than green sector for three times. Based on semi-quantitative RT-PCR, we found that the expression of both functional transcription of PsbO and variant transcription of PsbP are higher in yellow sector. It is suggested that yellow sector might accumulate more virus which result in the post-transcriptional regulation on PsbO and PsbP. Because PsbP play an important role in the stability of thylakoid folding, we suggested that the negative regulation of PsbP will block the development of thylakoid in yellow sector. It causes the chlorophyll can not accumulate in the yellow sector, as a result, the variegated leaves are shown.
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