Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
The Partner State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Sci Rep. 2017 Apr 12;7:46433. doi: 10.1038/srep46433.
Small RNAs are important regulators for a variety of biological processes, including leaf development, flowering-time, embryogenesis and defense responses. miR163 is a non-conserved miRNA and its locus has evolved recently through inverted duplication of its target genes to which they belong to the SABATH family of related small-molecule methyltransferases (MTs). In Arabidopsis thaliana, previous study demonstrated that miR163 accumulation was induced by alamethicin treatment, suggesting its roles in defense response pathways. Enhanced resistance against Pseudomonas syringae pv. tomato (Pst) was observed in the mir163 mutant, whereas transgenic lines overexpressing miR163 showed increase sensitivity to Pst, suggesting that miR163 is a negative regulator of defense response. Elevated level of miR163 and its targets in A. thaliana were observed upon Pst treatment, suggesting a modulating relationship between miR163 and its targets. In addition, miR163 and histone deacetylase were found to act cooperatively in mediating defense against Pst. Transgenic plants overexpressing miR163-resistant targets suggested their different contributions in defense. Results from this study revealed that the stress-inducible miR163 and its targets act in concert to modulate defense responses against bacterial pathogen in A. thaliana.
小 RNA 是多种生物过程的重要调节因子，包括叶片发育、开花时间、胚胎发生和防御反应。miR163 是一种非保守的 miRNA，其基因座最近通过其靶基因的反向重复进化而来，这些靶基因属于 SABATH 家族的相关小分子甲基转移酶 (MTs)。在拟南芥中，先前的研究表明，miR163 的积累是由阿拉霉素处理诱导的，表明其在防御反应途径中的作用。miR163 突变体对丁香假单胞菌 pv.番茄 (Pst) 的抗性增强，而过表达 miR163 的转基因系对 Pst 的敏感性增加，表明 miR163 是防御反应的负调节剂。在 Pst 处理后，拟南芥中 miR163 和其靶标的水平升高，表明 miR163 和其靶标之间存在调节关系。此外，miR163 和组蛋白去乙酰化酶被发现协同作用于介导拟南芥对 Pst 的防御。过表达 miR163 抗性靶标的转基因植物表明它们在防御中具有不同的贡献。这项研究的结果表明，应激诱导的 miR163 及其靶标协同作用，调节拟南芥对细菌病原体的防御反应。
