Graduate School of Science, Nagoya University, B-105, Bldg B, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan,
J Plant Res. 2015 Jan;128(1):27-35. doi: 10.1007/s10265-014-0675-6. Epub 2014 Dec 17.
Signaling between cells, tissues and organs is essential for multicellular organisms to coordinate and adapt their development and growth to internal and environmental changes. Plants have evolved a plant-specific symplasmic pathway, called plasmodesmata, for efficient intercellular communication, in addition to the receptor-ligand-based apoplasmic pathway. Long-distance signaling between distant organs is enabled via the phloem tube system, where plasmodesmata contribute to phloem loading and unloading for photosynthate allocation. In addition to signaling by small molecules such as metabolites and phytohormones, the transport of proteins, small RNAs and mRNAs is also considered an important mechanism to achieve long-distance signaling in plants. Recent studies on phloem-mobile proteins and small RNAs have revealed their role in crucial physiological processes including flowering, systemic silencing and nutrient allocation. However, the biological role of mRNAs found in the phloem tube is not yet clear, though their mobility over long-distances has been well evidenced. To gain this knowledge, it is important to collect further information on mRNA profiles in the phloem translocation stream. In this review, I summarize the current approaches to identifying the mRNA population in the phloem translocation system, and discuss the possible role of short- and long-distance mRNA transport.
细胞、组织和器官之间的信号传递对于多细胞生物协调和适应其发育和生长以应对内部和环境变化至关重要。植物除了基于受体-配体的质外体途径外，还进化出了一种植物特有的胞质途径，称为胞间连丝，以实现有效的细胞间通讯。通过韧皮部管系统实现远距离器官之间的长距离信号传递，其中胞间连丝有助于光合产物分配的韧皮部装载和卸载。除了代谢物和植物激素等小分子的信号传递外，蛋白质、小 RNA 和 mRNA 的运输也被认为是植物中实现长距离信号传递的重要机制。最近对韧皮部移动蛋白和小 RNA 的研究揭示了它们在包括开花、系统沉默和养分分配在内的关键生理过程中的作用。然而，在韧皮部管中发现的 mRNA 的生物学作用尚不清楚，尽管它们在长距离上的移动性已经得到了很好的证明。为了获得这些知识，重要的是要收集更多关于韧皮部转运流中 mRNA 谱的信息。在这篇综述中，我总结了目前鉴定韧皮部转运系统中 mRNA 群体的方法，并讨论了短距离和长距离 mRNA 运输的可能作用。
