Recent loss of plastid-encoded ndh genes within Erodium (Geraniaceae)
Recent loss of plastid-encoded ndh genes within Erodium (Geraniaceae)
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DOI：
10.1007/s11103-011-9753-5
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发表时间：
2011-07-01
影响因子：
5.1
通讯作者：
Jansen, Robert K.
中科院分区：
文献类型：
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作者：
Chris Blazier, J.;Guisinger, Mary M.;Jansen, Robert K.
已知显花植物老鹳草科中的质体基因组基于代表四个主要属的全序列被高度重排，所述四个主要属为牛筋草属、大蓟属、Monsonia属和天竺葵属。在本文中，我们报告的基因组序列的第二种Erodium，E。carvifolium，代表该属的进化史中的第二个主要分支（分支II）。将该基因组序列与先前发表的E. texanum的质粒基因组编码相同数量的蛋白质，但在相对重排程度上有很大差异。texanum的质体基因组含有与重排终点相关的复杂重复序列，而E.香芹叶是116 kb的流线型，在基因顺序上没有显示出独特的改变。此外，这两个主要分支的Erodium的物种含有完整的NADH脱氢酶（ndh）基因，但11个ndh基因是假基因在一个小分支的13个物种。目前还不清楚质体编码的ndh基因是否已经完全丢失或功能转移到细胞核。这是第三个关于ndh基因缺失的报道，目前的研究描述了这些基因在光合种子植物中的最近一次缺失，以及被子植物中的第二次缺失。松科/买麻藤目和兰科的其他ndh损失要古老得多。比较生物化学与不含质体编码的NDH基因的Erodium物种之间可能阐明光合功能的变化和Ndh复合物的作用。
Plastid genomes in the flowering plant family Geraniaceae are known to be highly rearranged based on complete sequences representing the four major genera Erodium, Geranium, Monsonia, and Pelargonium. In this paper we report on the genome sequence of a second species of Erodium, E. carvifolium, representing the second major clade (clade II) in the phylogeny of this genus. Comparison of this genome sequence to the previously published sequence of E. texanum from clade I demonstrates that the plastid genomes of these two species encode the same number of proteins but differ greatly in their relative degree of rearrangement; 14 kb of additional sequence in E. texanum contains complex repeats associated with rearrangement endpoints, whereas the plastid genome of E. carvifolium is streamlined at 116 kb and displays no unique alterations in gene order. Furthermore, these species from both major clades of Erodium contain intact NADH dehydrogenase (ndh) genes, but the 11 ndh genes are represented as pseudogenes in a small clade of 13 species. It is unclear whether plastid-encoded ndh genes have been lost entirely or functionally transferred to the nucleus. This is the third report of the absence of functional ndh genes, and the current study describes the most recent loss of these genes among photosynthetic seed plants and the second such loss among angiosperms. The other ndh losses from Pinaceae/Gnetales and Orchidaceae are much more ancient. Comparative biochemistry between Erodium species with and without plastid-encoded ndh genes may elucidate changes in photosynthetic function and the role of the Ndh complex.