Waksman Institute, Rutgers University, Piscataway, NJ 08854, USA.
Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2439-43. doi: 10.1073/pnas.1114297109. Epub 2012 Jan 30.
Our objective was to test whether or not plastids and mitochondria, the two DNA-containing organelles, move between cells in plants. As our experimental approach, we grafted two different species of tobacco, Nicotiana tabacum and Nicotiana sylvestris. Grafting triggers formation of new cell-to-cell contacts, creating an opportunity to detect cell-to-cell organelle movement between the genetically distinct plants. We initiated tissue culture from sliced graft junctions and selected for clonal lines in which gentamycin resistance encoded in the N. tabacum nucleus was combined with spectinomycin resistance encoded in N. sylvestris plastids. Here, we present evidence for cell-to-cell movement of the entire 161-kb plastid genome in these plants, most likely in intact plastids. We also found that the related mitochondria were absent, suggesting independent movement of the two DNA-containing organelles. Acquisition of plastids from neighboring cells provides a mechanism by which cells may be repopulated with functioning organelles. Our finding supports the universality of intercellular organelle trafficking and may enable development of future biotechnological applications.
我们的目的是检验植物细胞之间是否存在含有 DNA 的两种细胞器——质体和线粒体的转移。为此,我们采用了不同种的烟草(Nicotiana tabacum 和 Nicotiana sylvestris)进行嫁接。嫁接会触发新的细胞间接触的形成,从而有机会在遗传上不同的植物之间检测到细胞间细胞器的转移。我们从嫁接连接处的切片开始进行组织培养,并选择了克隆系,其中在 N. tabacum 核中编码的庆大霉素抗性与在 N. sylvestris 质体中编码的壮观霉素抗性相结合。在这里,我们提供了证据表明这些植物中整个 161kb 的质体基因组发生了细胞间转移,很可能是在完整的质体中。我们还发现相关的线粒体不存在,这表明这两种含有 DNA 的细胞器是独立转移的。从邻近细胞获得质体为细胞提供了一种用功能正常的细胞器重新填充的机制。我们的发现支持了细胞间细胞器运输的普遍性,并可能为未来的生物技术应用提供支持。