Multiple recent horizontal transfers of the cox1 intron in Solanaceae and extended co-conversion of flanking exons.
Multiple recent horizontal transfers of the cox1 intron in Solanaceae and extended co-conversion of flanking exons.
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DOI：
10.1186/1471-2148-11-277
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发表时间：
2011-09-27
影响因子：
3.4
通讯作者：
Palmer JD
中科院分区：
文献类型：
--
作者：
Sanchez-Puerta MV;Abbona CC;Zhuo S;Tepe EJ;Bohs L;Olmstead RG;Palmer JD
在植物中最常见的水平转移涉及线粒体基因cox1中的第一组内含子，该内含子是通过在所研究的833种不同被子植物中的大约80个独立的植物间转移事件获得的。该内含子编码一种内切酶，被认为促进了内含子的混杂行为。研究核酸内切酶活性和内含子传递的一种有前景的实验方法是体细胞杂交，它在植物中导致线粒体融合和基因组重组。然而，cox1内含子还没有在植物体细胞遗传学的理想类群-茄科中被发现。因此，我们对这个家族进行了广泛的调查，以寻找具有内含子的成员，并了解更多关于这种异常可移动的遗传元件的进化史。虽然在所研究的426种茄科植物中有409种缺乏cox1内含子，但它统一存在于三个不同的系统发育分支中。尽管cox1内含子系统发育与被子植物系统发育有很大的不一致性，但其中两个分支具有几乎相同的内含子序列，在内含子系统发育上是单系进化。这两个分支，也可能是第三个分支，在内含子下游包含一个协同转换区(CCT)，相对于被子植物Cox1中所有先前发现的CCT而延伸。对所有已发表的cox1基因的重新检查发现了更多延长共转化的病例，并发现了一例罕见的假定内含子丢失，伴随着CCT的完全保留。我们推测，cox1内含子是分别由至少三个不同的茄科谱系最近获得的。来自其中两个谱系的内含子和CCT的惊人同源性表明，这三个内含子捕获中的一个可能是通过家族内转移事件发生的。这与之前的证据一致，即植物中的水平转移偏向于系统发育上的局部事件。延长共转化的发现表明，其他cox1转化可能比人们所认识到的更长，但被植物线粒体序列的特殊保守所掩盖。我们的发现进一步支持了cox1内含子进化的猖獗转移模型，并推荐茄科植物作为植物cox1内含子转移的实验分析的模型系统。
The most frequent case of horizontal transfer in plants involves a group I intron in the mitochondrial gene cox1, which has been acquired via some 80 separate plant-to-plant transfer events among 833 diverse angiosperms examined. This homing intron encodes an endonuclease thought to promote the intron's promiscuous behavior. A promising experimental approach to study endonuclease activity and intron transmission involves somatic cell hybridization, which in plants leads to mitochondrial fusion and genome recombination. However, the cox1 intron has not yet been found in the ideal group for plant somatic genetics - the Solanaceae. We therefore undertook an extensive survey of this family to find members with the intron and to learn more about the evolutionary history of this exceptionally mobile genetic element. Although 409 of the 426 species of Solanaceae examined lack the cox1 intron, it is uniformly present in three phylogenetically disjunct clades. Despite strong overall incongruence of cox1 intron phylogeny with angiosperm phylogeny, two of these clades possess nearly identical intron sequences and are monophyletic in intron phylogeny. These two clades, and possibly the third also, contain a co-conversion tract (CCT) downstream of the intron that is extended relative to all previously recognized CCTs in angiosperm cox1. Re-examination of all published cox1 genes uncovered additional cases of extended co-conversion and identified a rare case of putative intron loss, accompanied by full retention of the CCT. We infer that the cox1 intron was separately and recently acquired by at least three different lineages of Solanaceae. The striking identity of the intron and CCT from two of these lineages suggests that one of these three intron captures may have occurred by a within-family transfer event. This is consistent with previous evidence that horizontal transfer in plants is biased towards phylogenetically local events. The discovery of extended co-conversion suggests that other cox1 conversions may be longer than realized but obscured by the exceptional conservation of plant mitochondrial sequences. Our findings provide further support for the rampant-transfer model of cox1 intron evolution and recommend the Solanaceae as a model system for the experimental analysis of cox1 intron transfer in plants.
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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：
10.7
作者：
Cusimano, Natalie;Zhang, Li-Bing;Renner, Susanne S.
通讯作者：
Renner, Susanne S.
影响因子：
64.5
作者：
DELAHODDE, A;GOGUEL, V;JACQ, C
通讯作者：
JACQ, C
影响因子：
56.9
作者：
Davis, CC;Wurdack, KJ
通讯作者：
Wurdack, KJ
影响因子：
46.9
作者：
Giddings, G;Allison, G;Carter, A
通讯作者：
Carter, A