Department of Agronomy, Purdue University, West Lafayette, IN, USA.
College of Life Sciences, Qingdao Agricultural University, Qingdao, China.
Nat Plants. 2021 Jan;7(1):50-59. doi: 10.1038/s41477-020-00829-2. Epub 2021 Jan 15.
Long-distance RNA movement is important for plant growth and environmental responses; however, the extent to which RNAs move between distant tissues, their relative magnitude and functional importance remain to be elucidated on a genomic scale. Using a soybean (Glycine max)-common bean (Phaseolus vulgaris) grafting system, we identified 100 shoot-root mobile microRNAs and 32 shoot-root mobile phased secondary small interfering RNAs (phasiRNAs), which were predominantly produced in shoots and transported to roots, and, in most cases, accumulated to a level similar to that observed in shoots. Many of these microRNAs or phasiRNAs enabled cleavage of their messenger RNA targets or phasiRNA precursors in roots. In contrast, most mobile-capable mRNAs were transcribed in both shoots and roots, with only small proportions transported to recipient tissues. These findings suggest that the regulatory mechanisms for small RNA movement are different from those for mRNA movement, and that the former is more strictly regulated and, probably, more functionally important than the latter.
长距离 RNA 运动对植物生长和环境响应很重要；然而，在基因组范围内，RNA 在不同组织之间的移动程度、相对丰度和功能重要性仍有待阐明。利用大豆（Glycine max）-菜豆（Phaseolus vulgaris）嫁接系统，我们鉴定了 100 个 shoot-root 移动 microRNAs 和 32 个 shoot-root 移动相二级小干扰 RNA（phasiRNAs），它们主要在 shoots 中产生并运输到 roots 中，并且在大多数情况下积累到与在 shoots 中观察到的水平相似。这些 microRNAs 或 phasiRNAs 中的许多能够在 roots 中切割它们的 mRNA 靶标或 phasiRNA 前体。相比之下，大多数具有移动能力的 mRNA 在 shoots 和 roots 中都被转录，只有一小部分被运输到受体组织。这些发现表明，小 RNA 运动的调节机制与 mRNA 运动的调节机制不同，前者受到更严格的调控，并且可能比后者更具功能重要性。
