LOSS OF PHOTOSYNTHETIC AND CHLORORESPIRATORY GENES FROM THE PLASTID GENOME OF A PARASITIC FLOWERING PLANT
LOSS OF PHOTOSYNTHETIC AND CHLORORESPIRATORY GENES FROM THE PLASTID GENOME OF A PARASITIC FLOWERING PLANT
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DOI：
10.1038/348337a0
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发表时间：
1990-11-22
期刊：
影响因子：
64.8
通讯作者：
PALMER, JD
中科院分区：
文献类型：
--
作者：
DEPAMPHILIS, CW;PALMER, JD
光合作用是植物生命的标志，也是唯一已知由质体基因控制的质体代谢过程1，2。完全丧失光合能力，但是，发生在几个独立的场合在寄生开花植物3，4。已知这些植物中的一些缺乏叶绿素和某些光合酶4，但不知道编码光合机构的基因发生了多大程度的变化，或者植物是否甚至保持质体基因组。在这里，我们报告说，nonphotosynthetic根寄生Epifagus virginiana有一个质体染色体只有71个酶的大小，远远小于任何以前表征的陆地植物质体基因组5。Epifagusplastid基因组已经失去了大多数，如果不是全部的话，30个或更多的叶绿体光合作用基因和一个大家族的质体基因，thendh基因，其产物可能参与质体呼吸链6 -9。Epifagusplastid基因含量的广泛变化一定发生在相对较短的时间内（5-50 × 106年），因为Striga asiatica，一种相关的光合作用寄生虫，具有典型的光合作用和叶绿体呼吸基因的互补。Epifagus的质体基因组保留了转录的核糖体RNA和核糖体蛋白基因，这表明它表达了一个或多个与光合作用无关的质体功能基因产物。
PHOTOSYNTHESIS is the hallmark of plant life and is the only plastid metabolic process known to be controlled by plastid genes1,2. The complete loss of photosynthetic ability, however, has occurred on several independent occasions in parasitic flowering plants3,4. Some of these plants are known to lack chlorophyll and certain photosynthetic enzymes4, but it is not known to what extent changes have occurred in the genes encoding the photosynthetic apparatus or whether the plants even maintain a plastid genome. Here we report that the nonphotosynthetic root parasiteEpifagus virginianahas a plastid chromosome only 71 kilobases in size, far smaller than any previously characterized land plant plastid genome5. TheEpifagusplastid genome has lost most, if not all, of the 30 or more chloroplast genes for photosynthesis and most of a large family of plastid genes, thendhgenes, whose products may be involved in a plastid respiratory chain6–9. The extensive changes inEpifagusplastid gene content must have occurred in a relatively short time (5–50 x 106yr), becauseStriga asiatica, a related photosynthetic parasite, has a typical complement of chloroplast genes for photosynthesis and chlororespiration. The plastid genome ofEpifagushas retained transcribed ribosomal RNA and ribosomal protein genes, suggesting that it expresses one or more gene products for plastid functions not related to photosynthesis.