Horticulture Department, College of Horticulture, Shenyang Agricultural University, No. 120 Dongling Road, Shenhe District, Shenyang, 110866, P.R. China.
Key Laboratory of Protected Horticulture of Ministry of Education, No. 120 Dongling Road, Shenhe District, Shenyang, 110866, P.R. China.
BMC Plant Biol. 2020 Oct 19;20(1):477. doi: 10.1186/s12870-020-02660-5.
Potassium (K) is an essential ion for most plants, as it is involved in the regulation of growth and development. K homeostasis in plant cells has evolved to facilitate plant adaptation to K-deficiency stress. Argonaute1 (AGO1) is regulated by miR168 to modulate the small RNA regulatory pathway by RNA silencing complex (RISC) in tomatoes. However, the role of miR168-mediated regulation of AGO1 in the context of K deficiency stress in tomatoes has not been elucidated yet.
SlmiR168 and its target gene SlAGO1A were differentially expressed among low-K-tolerant JZ34 and low-K-sensitive JZ18 tomato plants. Transgenic tomato plants constitutively expressing pri-SlmiR168a showed stronger root system growth, better leaves development, and higher K contents in roots under K-deficiency stress than those of the transgenic tomato lines expressing rSlAGO1A (SlmiR168-resistant) and the wild type (WT). Deep sequencing analysis showed that 62 known microRNAs (miRNAs) were up-regulated in 35S:rSlAGO1 compared with WT tomatoes. The same miRNAs were down-regulated in 35S:SlmiR168a compared with WT plants. The integrated analysis found 12 miRNA/mRNA pairs from the 62 miRNAs, including the root growth and cytokinin (CTK)/abscisic acid (ABA) pathways.
The regulation mediated by SlmiR168 of SlAGO1A contributes to the plant development under low-K stress. Moreover, this regulation mechanism may influence downstream miRNA pathways in response to low-K stress through the CTK/ABA and root growth modulation pathways.
钾（K）是大多数植物必需的离子，因为它参与了生长和发育的调节。植物细胞中的 K 稳态进化以促进植物适应 K 缺乏胁迫。Argonaute1（AGO1）受 miR168 调控，通过 RNA 沉默复合物（RISC）调节番茄中的小 RNA 调控途径。然而，miR168 介导的 AGO1 调控在番茄 K 缺乏胁迫背景下的作用尚未阐明。
在低 K 耐性 JZ34 和低 K 敏感 JZ18 番茄植株中，SlmiR168 和其靶基因 SlAGO1A 差异表达。过表达 pri-SlmiR168a 的转基因番茄植株在 K 缺乏胁迫下的根系生长更强，叶片发育更好，根中的 K 含量更高，而表达 rSlAGO1A（SlmiR168 抗性）和野生型（WT）的转基因番茄植株则较差。深度测序分析表明，与 WT 番茄相比，35S：rSlAGO1 中有 62 个已知 miRNA（miRNAs）上调。与 WT 植物相比，35S：SlmiR168a 中相同的 miRNAs 下调。整合分析发现，在 62 个 miRNAs 中，包括根生长和细胞分裂素（CTK）/脱落酸（ABA）途径，有 12 个 miRNA/mRNA 对。
SlmiR168 对 SlAGO1A 的调控有助于植物在低 K 胁迫下的发育。此外，这种调控机制可能通过 CTK/ABA 和根生长调节途径影响下游 miRNA 途径对低 K 胁迫的响应。
