Plastid genome evolution across the genus Cuscuta (Convolvulaceae): two clades within subgenus Grammica exhibit extensive gene loss.
Plastid genome evolution across the genus Cuscuta (Convolvulaceae): two clades within subgenus Grammica exhibit extensive gene loss.
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DOI：
10.1093/jxb/ers391
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发表时间：
2013-02
影响因子：
6.9
通讯作者：
Stefanovic S
中科院分区：
文献类型：
--
作者：
Braukmann T;Kuzmina M;Stefanovic S
菟丝子属（旋花科，牵牛花科）是寄生植物研究最深入的谱系之一。四个菟丝子属物种的全质体组测序表明质体基因内容和结构的变化。纯化选择条件下的光合作用基因的存在表明菟丝子属植物具有潜在的光合作用。然而，质体基因组进化的克里思和模式在这一组（约200种）的多样性在很大程度上仍然未知。质体基因组含量的比较调查，接地系统发育框架内，进行了使用狭缝印迹Southern杂交方法。菟丝子被广泛采样（约56%的物种），包括以前建议拥有更多的改变与本属的其他成员相比，塑性体的群体。共使用了56种来自所有类别的蛋白质编码基因的探针，这些基因通常在开花植物的质体中发现。结果表明，两个分支内的亚属Grammica（分支'O'和'K'）表现出显着更多的质体基因丢失相对于其他成员的菟丝子。所有调查的成员的'O'进化枝显示广泛的损失的质体基因，从每一类基因通常发现在质体，包括否则高度保守的小和大核糖体亚基。在这个分支的质体基因损失的程度是类似的幅度，以前观察到的一些non-pandroid holoparasites，其中质体的存在受到质疑。'K'进化枝也表现出相当大的质体基因的损失。与所有物种似乎都受到影响的“O”分支不同，分支“K”的损失是遗传性的，遵循与进化过渡系列假说一致的模式。这个分支提供了一个理想的机会，研究减少的质体寄生虫的“行动”。在这两个分支中广泛的质体基因丢失被假设为光合作用完全丧失的结果。此外，分类群，这将是最好的候选人，整个质体测序确定，以进一步调查的损失，光合作用和减少的质体内菟丝子。
The genus Cuscuta (Convolvulaceae, the morning glory family) is one of the most intensely studied lineages of parasitic plants. Whole plastome sequencing of four Cuscuta species has demonstrated changes to both plastid gene content and structure. The presence of photosynthetic genes under purifying selection indicates that Cuscuta is cryptically photosynthetic. However, the tempo and mode of plastid genome evolution across the diversity of this group (~200 species) remain largely unknown. A comparative investigation of plastid genome content, grounded within a phylogenetic framework, was conducted using a slot-blot Southern hybridization approach. Cuscuta was extensively sampled (~56% of species), including groups previously suggested to possess more altered plastomes compared with other members of this genus. A total of 56 probes derived from all categories of protein-coding genes, typically found within the plastomes of flowering plants, were used. The results indicate that two clades within subgenus Grammica (clades ‘O’ and ‘K’) exhibit substantially more plastid gene loss relative to other members of Cuscuta. All surveyed members of the ‘O’ clade show extensive losses of plastid genes from every category of genes typically found in the plastome, including otherwise highly conserved small and large ribosomal subunits. The extent of plastid gene losses within this clade is similar in magnitude to that observed previously in some non-asterid holoparasites, in which the very presence of a plastome has been questioned. The ‘K’ clade also exhibits considerable loss of plastid genes. Unlike in the ‘O’ clade, in which all species seem to be affected, the losses in clade ‘K’ progress phylogenetically, following a pattern consistent with the Evolutionary Transition Series hypothesis. This clade presents an ideal opportunity to study the reduction of the plastome of parasites ‘in action’. The widespread plastid gene loss in these two clades is hypothesized to be a consequence of the complete loss of photosynthesis. Additionally, taxa that would be the best candidates for entire plastome sequencing are identified in order to investigate further the loss of photosynthesis and reduction of the plastome within Cuscuta.
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影响因子：
3.4
作者：
Barkman TJ;McNeal JR;Lim SH;Coat G;Croom HB;Young ND;Depamphilis CW
通讯作者：
Depamphilis CW
影响因子：
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