State Key Laboratory of Agrobiotechnology, College of Horticulture, China Agricultural University, Beijing, 100193, China.
Department of Agronomy and Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, 47907, USA.
Plant Physiol. 2021 Nov 3;187(3):1587-1604. doi: 10.1093/plphys/kiab366.
Long-distance mobile mRNAs play key roles in gene regulatory networks that control plant development and stress tolerance. However, the mechanisms underlying species-specific delivery of mRNA still need to be elucidated. Here, the use of grafts involving highly heterozygous apple (Malus) genotypes allowed us to demonstrate that apple (Malus domestica) oligopeptide transporter3 (MdOPT3) mRNA can be transported over a long distance, from the leaf to the root, to regulate iron uptake; however, the mRNA of Arabidopsis (Arabidopsis thaliana) oligopeptide transporter 3 (AtOPT3), the MdOPT3 homolog from A. thaliana, does not move from shoot to root. Reciprocal heterologous expression of the two types of mRNAs showed that the immobile AtOPT3 became mobile and moved from the shoot to the root in two woody species, Malus and Populus, while the mobile MdOPT3 became immobile in two herbaceous species, A. thaliana and tomato (Solanum lycopersicum). Furthermore, we demonstrated that the different transmissibility of OPT3 in A. thaliana and Malus might be caused by divergence in RNA-binding proteins between herbaceous and woody plants. This study provides insights into mechanisms underlying differences in mRNA mobility and validates the important physiological functions associated with this process.
长距离移动 mRNA 在调控植物发育和胁迫耐受的基因调控网络中发挥关键作用。然而，mRNA 物种特异性运输的机制仍需阐明。本研究利用高度杂合苹果（Malus）基因型的接穗，证明了苹果（Malus domestica）寡肽转运蛋白 3（MdOPT3）mRNA 可以远距离运输，从叶片到根部，以调节铁的吸收；然而，拟南芥（Arabidopsis thaliana）寡肽转运蛋白 3（AtOPT3）的 mRNA，即 A. thaliana 的 MdOPT3 同源物，不能从地上部分转移到根部。两种类型的 mRNA 的正反交异源表达表明，不移动的 AtOPT3 在两种木本植物苹果和杨树中变得移动，并从地上部分转移到根部，而移动的 MdOPT3 在两种草本植物拟南芥和番茄中变得不移动。此外，我们证明了 OPT3 在拟南芥和苹果中的不同可传递性可能是由于草本植物和木本植物之间 RNA 结合蛋白的差异造成的。本研究为理解 mRNA 迁移性差异的机制提供了新的见解，并验证了与该过程相关的重要生理功能。
