Lack of a functional plastid tRNA(Cys) gene is associated with loss of photosynthesis in a lineage of parasitic plants.
Lack of a functional plastid tRNA(Cys) gene is associated with loss of photosynthesis in a lineage of parasitic plants.
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功能性质体 tRNA(Cys) 基因的缺乏与寄生植物谱系中光合作用的丧失有关。
DOI：
10.1007/bf00334780
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发表时间：
1991
期刊：
影响因子：
2.5
通讯作者：
Palmer,JD
中科院分区：
文献类型：
--
作者：
Taylor,GW;Wolfe,KH;Morden,CW;dePamphilis,CW;Palmer,JD
我们最近报道了列当科非光合寄生开花植物--由于这是质体基因组中唯一的tRNACys基因，而且Epifagus似乎具有一个功能性质体翻译装置，因此核编码的tRNA很可能被导入质体中以实现翻译。在这项研究中，我们调查了与Epifagus密切相关的物种，以确定这种tRNA基因的丢失有多普遍。我们发现，另一种非光合作用的寄生虫美洲芋螺完全缺乏该基因，但7种密切相关的光合作用植物（寄生和自由生活）保持了完整的叶绿体tRNACys基因。因此，tRNACysgene似乎在光合能力丧失的同时变得无功能。这可能是因为只有在非光合作用条件下，质粒导入的tRNA水平才足以满足质体基因表达的需求。
We recently reported that the gene for chloroplast tRNACys(GCA) is a pseudogene in the plastid DNA ofEpifagus virginiana, a non-photosynthetic parastic flowering plant in the family Orobanchaceae. Since this is the only tRNACysgene in the plastid genome, and sinceEpifagusappears to possess a functional plastid translational apparatus, it seems probable that nuclear-encoded tRNAs are imported into plastids to effect translation. In this study we have surveyed species closely related toEpifagusto establish how widespread the loss of this tRNA gene has been. We find thatConopholis americana, another non-photosynthetic parasite, lacks the gene altogether, but that seven closely-related photosythetic plants (both parasitic and free-living) maintain an intact chloroplast tRNACysgene. Thus, the tRNACysgene appears to have become non-functional at the same time that photosynthetic ability was lost. This may be because the levels of putatively imported tRNAs are sufficient to meet the demands of plastid gene expression under nonphotosynthetic conditions only.