An increasing number of microRNAs (miRNAs) and miRNA‐related sequences produced during miRNA biogenesis, comprising the isomiRome, have been recently highlighted in different species as critical mediators of environmental stress responses. Conifers have some of the largest known genomes but an extensive characterization of the isomiRome from any conifer species has been lacking. We provide here a comprehensive overview of the Pinus pinaster isomiRome expressed in roots, stem and needles under well‐watered and drought conditions. From the 13,441 unique small RNA sequences identified, 2,980 were annotated as canonical miRNAs or miRNA* and the remaining were classified as isomiRNA or miRNA‐like sequences. A survey of their expression patterns highlighted roots as the most responsive organ under drought, where specific sequences of which a 24‐nt novel miRNA stood out, were strongly down‐regulated. Given the putative roles of the miRNA‐targeted transcripts validated specifically in root tissues, some of the miRNAs, conserved and novel, are shortlisted as potential regulators of drought response. These results provide a valuable resource for comparative studies between gymnosperms and angiosperms. Furthermore, it evidences high transferability of the isomiRome between pine species being a useful basis for further molecular regulation and physiological studies, and especially those focused on adaptation to drought conditions.

中文翻译：

---

水分利用率对比下针叶松人工林营养器官等值基因的综合分析

最近在miRNA生物发生过程中产生的越来越多的microRNA（miRNA）和miRNA相关序列（包括isomiRome）已在不同物种中得到强调，它们是环境胁迫反应的关键介体。针叶树具有一些最大的已知基因组，但缺乏对任何针叶树种的isomiRome的广泛表征。我们在这里提供Pinus pinaster的全面概述在水分充足和干旱的条件下，在根，茎和针中表达等位基因。在鉴定出的13441个独特的小RNA序列中，有2980个被注释为标准miRNA或miRNA *，其余被分类为isomiRNA或miRNA样序列。对它们的表达模式进行的一项调查显示，根是干旱下反应最迅速的器官，其中特定序列（其中24-nt新miRNA脱颖而出）被强烈下调。鉴于专门在根组织中验证的针对miRNA的转录本的推定作用，一些保守且新颖的miRNA被入选为干旱响应的潜在调节剂。这些结果为裸子植物和被子植物之间的比较研究提供了宝贵的资源。此外，