School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.
College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK.
Philos Trans R Soc Lond B Biol Sci. 2020 Jun 22;375(1801):20190405. doi: 10.1098/rstb.2019.0405. Epub 2020 May 4.
Communication between chloroplasts and the nucleus in response to various environmental cues may be mediated by various small molecules. Signalling specificity could be enhanced if the physical contact between these organelles facilitates direct transfer and prevents interference from other subcellular sources of the same molecules. Plant cells have plastid-nuclear complexes, which provide close physical contact between these organelles. Plastid-nuclear complexes have been proposed to facilitate transfer of photosynthesis-derived HO to the nucleus in high light. Stromules (stroma filled tubular plastid extensions) may provide an additional conduit for transfer of a wider range of signalling molecules, including proteins. However, plastid-nuclear complexes and stromules have been hitherto treated as distinct phenomena. We suggest that plastid-nuclear complexes and stromules work in a coordinated manner so that, according to environmental conditions or developmental state, the two modes of connection contribute to varying extents. We hypothesize that this association is dynamic and that there may be a link between plastid-nuclear complexes and the development of stromules. Furthermore, the changes in contact could alter signalling specificity by allowing an extended or different range of signalling molecules to be delivered to the nucleus. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
叶绿体与细胞核之间针对各种环境信号的通讯，可能是由各种小分子介导的。如果这些细胞器之间的物理接触有助于直接传递，并且防止来自相同分子的其他亚细胞源的干扰，那么信号特异性可以得到增强。植物细胞具有质体-核复合物，为这些细胞器之间提供了紧密的物理接触。有人提出，质体-核复合物有助于在高光下将光合作用产生的 HO 转移到核中。类囊体（充满基质的管状质体延伸）可能为包括蛋白质在内的更广泛范围的信号分子的转移提供了另一种途径。然而，迄今为止，质体-核复合物和类囊体一直被视为不同的现象。我们认为，质体-核复合物和类囊体以协调的方式协同工作，因此，根据环境条件或发育状态，两种连接模式的贡献程度不同。我们假设这种关联是动态的，并且质体-核复合物与类囊体的发育之间可能存在联系。此外，接触的变化可以通过允许将更多或不同范围的信号分子传递到核中来改变信号特异性。本文是主题为“内共生细胞器的逆行信号”的一部分。
