非光合作用被子植物質體基因研究

Abstract

葉綠體存在於所有綠色植物體內，為 進行光合作用的場所。然而有些被子植物 喪失光合作用的能力，成為全寄生或腐生 的植物。這些非光合作用植物卻仍然保有 一個縮減的質體基因組，其中大部分與光 合作用相關的基因，如rbcL等，都已丟失 或成為偽基因(pseudogene) 。本計畫即以 九種台灣的非綠色被子植物為材料，進行 其質體基因的分析，探討質體基因的演 化。結果共獲得九條18S rDNA、七條16S rDNA序列，並依據其序列進行譜系分 析。另外穗花蛇菰、無根藤和列當均利用 PCR得到接近全長的rbcL與matK序列。但 是在菟絲子中只得到rbcL，而野菰只能得 到matK的序列。而RT-PCR的結果顯示菟 絲子的rbcL有微量表現，應具有些微光合 作用能力。

Chloroplasts are the eukaryotic organelles mainly responsible for photosynthesis. There are some flowering plants, however, lost the photosynthetic ability and became holoparasitic or saprophytic plants. The non-photosynthetic plants usually retain a reduced plastid genome, although many of plastid genes are lost or become pseudogenes, especially the photosynthesis-related genes such as rbcL. In order to elucidate the plastid genome evolution in non-photosynthetic plants, we examined nine non-photosynthetic plants native to Taiwan. We obtained all 18S rDNA sequences and seven 16S rDNA sequences of the examined taxa, and further using the sequences to perform phylogenetic analyses. In Balanophora, Cassytha and Orobanche, we obtained almost full length rbcL and matK sequences. However, we only obtained rbcL from Cuscuta and matK sequence from Aeginetia. The RT-PCR result shows that the rbcL transcripts were detected in Cuscuta, and suggests Cuscuta may have retain photosynthetic ability.