Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, China.
J Exp Bot. 2018 May 25;69(12):2979-2993. doi: 10.1093/jxb/ery132.
miR156 is a highly conserved plant miRNA and has been extensively studied because of its versatile roles in plant development. Here, we report a novel role of miR156 in regulating somatic embryogenesis (SE) in citrus, one of the most widely cultivated fruit crops in the world. SE is an important means of in vitro regeneration, but over the course of long-term sub-culturing there is always a decline in the SE potential of the preserved citrus embryogenic callus, and this represents a key obstacle for citrus biotechnology. In this study, the SE competence of citrus callus of wild kumquat (Fortunella hindsii) was significantly enhanced by either overexpression of csi-miR156a or by individual knock-down of the two target genes, CsSPL3 and CsSPL14, indicating that the effect of miR156-SPL modules was established during the initial phases of SE induction. Biological processes that might promote SE in response to miR156 overexpression were explored using RNA-seq, and mainly included hormone signaling pathways, stress responses, DNA methylation, and the cell cycle. CsAKIN10 was identified as interacting protein of CsSPL14. Our results provide insights into the regulatory pathway through which miR156-SPL modules enhance the SE potential of citrus callus, and provide a theoretical basis for improvement of plant SE competence.
miR156 是一种高度保守的植物 miRNA，因其在植物发育中的多种作用而被广泛研究。在这里，我们报告了 miR156 在调节柑橘体细胞胚胎发生（SE）中的一个新作用，柑橘是世界上种植最广泛的水果作物之一。SE 是体外再生的重要手段，但在长期的继代培养过程中，保存的柑橘胚性愈伤组织的 SE 潜能总是下降，这是柑橘生物技术的一个关键障碍。在这项研究中，通过过表达 csi-miR156a 或单独敲低两个靶基因 CsSPL3 和 CsSPL14，显著增强了野生金桔（ Fortunella hindsii）的柑橘愈伤组织的 SE 能力，表明 miR156-SPL 模块的作用是在 SE 诱导的初始阶段建立的。使用 RNA-seq 探索了可能促进 SE 响应 miR156 过表达的生物学过程，主要包括激素信号通路、应激反应、DNA 甲基化和细胞周期。鉴定出 CsAKIN10 是 CsSPL14 的互作蛋白。我们的研究结果提供了对 miR156-SPL 模块增强柑橘愈伤组织 SE 潜能的调控途径的深入了解，并为提高植物 SE 能力提供了理论基础。
