Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2434-8. doi: 10.1073/pnas.1114076109. Epub 2012 Jan 30.
The genomes of DNA-containing cell organelles (mitochondria, chloroplasts) can be laterally transmitted between organisms, a process known as organelle capture. Organelle capture often occurs in the absence of detectable nuclear introgression, and the capture mechanism is unknown. Here, we have considered horizontal genome transfer across natural grafts as a mechanism underlying chloroplast capture in plants. By grafting sexually incompatible species, we show that complete chloroplast genomes can travel across the graft junction from one species into another. We demonstrate that, consistent with reported phylogenetic evidence, replacement of the resident plastid genome by the alien genome occurs in the absence of intergenomic recombination. Our results provide a plausible mechanism for organelle capture in plants and suggest natural grafting as a path for horizontal gene and genome transfer between sexually incompatible species.
含有 DNA 的细胞器（线粒体、叶绿体）的基因组可以在生物之间横向传递，这个过程被称为细胞器捕获。细胞器捕获通常发生在没有可检测到的核基因渗入的情况下，其捕获机制尚不清楚。在这里，我们将跨自然嫁接的水平基因转移视为植物叶绿体捕获的潜在机制。通过嫁接不亲和的物种，我们证明完整的叶绿体基因组可以从一个物种穿过嫁接连接点转移到另一个物种。我们证明，与已报道的系统发育证据一致，在没有基因组间重组的情况下，外来基因组会取代驻留的质体基因组。我们的结果为植物细胞器捕获提供了一个合理的机制，并表明自然嫁接是不亲和性物种之间水平基因和基因组转移的途径。
