ORGANIZATION AND SEQUENCE OF PHOTOSYNTHETIC GENES FROM THE PLASTID GENOME OF THE HOLOPARASITIC FLOWERING PLANT CUSCUTA-REFLEXA
ORGANIZATION AND SEQUENCE OF PHOTOSYNTHETIC GENES FROM THE PLASTID GENOME OF THE HOLOPARASITIC FLOWERING PLANT CUSCUTA-REFLEXA
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DOI：
10.1007/bf00299148
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发表时间：
1992-03-01
期刊：
影响因子：
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通讯作者：
ZETSCHE, K
中科院分区：
文献类型：
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作者：
HABERHAUSEN, G;VALENTIN, K;ZETSCHE, K
我们从全寄生植物菟丝子中克隆并测序了约 6 kb 的质体 DNA (ptDNA)。 该区域包含（按以下顺序）细胞色素 b6/f 复合物亚基 V (petG)、tRNA(Val) (trnV)、tRNA(Met) (trnM)、叶绿体 ATP 合酶的 ε 和 β 亚基（atpE 和 atpB）以及核酮糖-1,5-二磷酸羧化酶/加氧酶大亚基的基因(Rubisco；rbcL)。 此外，我们通过异源杂交在 C. reflexa 中鉴定了其他光合作用相关基因（atpA、petB、psaA、psbA、psbB、psbC 和 psbD）。 除petG基因外，测序区域的基因排列与其他高等植物（例如烟草）的ptDNA相同。 菟丝子基因与高等植物的相应基因之间的序列同源性在 90% 范围内。 唯一显着的区别是，C. reflexa 的 rbcL 基因编码的多肽比其他高等植物长 18-23 个氨基酸。 这是值得注意的，因为 C. reflexa 已经失去了光自养生长的能力。 然而，与烟草相比，rbcL 基因的转录水平大大降低。 这些发现与蛋白质印迹分析的结果相一致，其中没有检测到 Rubisco 大亚基，并且 C. reflexa 粗提物中缺乏 Rubisco 活性。
We have cloned and sequenced an area of about 6 kb of the plastid DNA (ptDNA) from the holoparasitic plant Cuscuta reflexa. This region contains (in the following order) genes for the cytochrome b6/f-complex subunit V (petG), tRNA(Val) (trnV), tRNA(Met) (trnM), the epsilon- and beta-subunit of the chloroplast ATP-synthase (atpE and atpB) and the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; rbcL). In addition we identified other photosynthesis-related genes (atpA, petB, psaA, psbA, psbB, psbC, and psbD) in C. reflexa by heterologous hybridization. The gene arrangement of the sequenced area is, except for the petG gene, the same as in ptDNAs of other higher plants (e.g. Nicotiana tabacum). Sequence homologies between the Cuscuta genes and corresponding genes from higher plants are in the range of 90%. The only significant difference is that the rbcL gene of C. reflexa encodes a polypeptide which is 18-23 amino acids longer than in other higher plants. This is remarkable since C. reflexa has lost its ability to grow photoautotrophically. The transcript level of the rbcL gene, however, is strongly reduced as compared to tobacco. These findings are compatible with results from Western blotting analysis, where no Rubisco large subunit was detectable, and with the lack of Rubisco activity in crude extracts of C. reflexa.