Table2_The miR166–mRNA network regulates vascular tissue differentiation in Moso bamboo.XLSX

miR166s play an important role in plant tissue differentiation. However, the functions of miR166s in the differentiation of vascular tissue in bamboo have not yet been elucidated. Here, we showed that five miR166s are overexpressed (tags per million reads > 2,000) in underground shoot samples of wild-type (WT) Moso bamboo (Phyllostachys edulis) and a thick-walled variant (P. edulis “Pachyloen”) throughout the developmental process. Potential targets of these miR166s include some genes encoding homeodomain-leucine zipper (HD-ZIP) transcription factors and protein kinases. Cleavage sites for miR166s were identified in seven PeHD-ZIP homologs and a protein kinase gene via degradome sequencing (p < 0.05). Dual-luciferase and transient expression assays confirmed the binding of miR166s to PeHOXs. Fluorescence in situ hybridization revealed that miR166s were localized to the xylem of the leaf, root, and internode of 2-month-old pot seedlings of WT Moso bamboo. Overall, these findings reveal that miR166s are regulators of vascular tissue differentiation in bamboo. The miR166s identified in our study provide novel targets for bamboo breeding.

miR166s（microRNA166家族）在植物组织分化中发挥关键调控作用。然而，miR166s在竹类维管组织分化中的功能尚未被阐明。本研究发现，在野生型（wild-type，WT）毛竹（Phyllostachys edulis）及其厚壁变异株（P. edulis "Pachyloen"）的整个发育周期中，地下笋样本内共有5种miR166s呈现高表达（每百万测序标签数>2000）。这些miR166s的潜在靶基因包括若干编码同源域-亮氨酸拉链（homeodomain-leucine zipper, HD-ZIP）转录因子以及蛋白激酶的基因。通过降解组测序（degradome sequencing，p<0.05），我们在7个PeHD-ZIP同源基因以及1个蛋白激酶基因中鉴定到了miR166s的剪切位点。双荧光素酶报告基因实验与瞬时表达分析证实，miR166s可与PeHOXs结合。荧光原位杂交（fluorescence in situ hybridization, FISH）实验结果显示，miR166s定位于2月龄盆栽野生型毛竹幼苗的叶片、根系以及节间的木质部中。综上，本研究结果表明miR166s是竹类维管组织分化的调控因子。本研究中鉴定得到的miR166s可为竹类育种提供全新的靶标。