miR160 plays a crucial role in various biological processes by regulating their target gene auxin response factor (ARF) in plants. However, little is known about miR160 and ARF in cucumber fruit expansion. Here, 4 Csa-MIR160 family members and 17 CsARFs were identified through a genome-wide search. Csa-miR160 showed a closer relationship with those in melon. Phylogenetic analysis revealed that CsARFs were divided into four classes and most of CsARFs presented a closer evolutionary relationship with those from tomato. Putative cis-elements analysis predicted that Csa-MIR160 and CsARFs were involved in light, phytohormone and stress response, which proved that they might take part in light, phytohormone and stress signaling pathway by the miR160-ARF module. In addition, CsARF5, CsARF11, CsARF13 and CsARF14 were predicted as the target genes of Csa-miR160. qRT-PCR revealed that Csa-miR160 and their target gene CsARFs were differentially expressed in differential cucumber tissues and developmental stages. Csa-miR160d was only expressed in the expanded cucumber fruit. CsARF5, CsARF11 and CsARF13 exhibited the lower expression in the expanded fruit than those in the ovary, while, CsARF14 showed the reverse trend. Our results suggested that Csa-miR160d might play a crucial role in cucumber fruit expansion by negatively targeting CsARF5, CsARF11 and CsARF13. This is the first genome-wide analysis of miR160 in cucumber. These findings provide useful information and resources for further studying the role of miR160 and ARF in cucumber fruit expansion.

miR160通过调控其靶基因生长素反应因子（ ARF）在植物中的多种生物学过程中发挥着至关重要的作用。然而，关于黄瓜果实扩张中的miR160和ARF知之甚少。在这里，通过全基因组搜索确定了4 个 Csa-MIR160 家族成员和 17 个CsARF 。Csa-miR160 与甜瓜中的关系更密切。系统发育分析表明，CsARFs分为四类，大多数CsARFs与来自番茄的 CsARFs 具有更密切的进化关系。推定的顺式元素分析预测 Csa-MIR160 和CsARFs参与光、植物激素和应激反应，证明它们可能通过miR160- ARF模块参与光、植物激素和应激信号通路。此外，CsARF 5、CsARF 11、CsARF 13和CsARF 14被预测为Csa-miR160的靶基因。qRT-PCR显示Csa-miR160及其靶基因CsARFs在不同的黄瓜组织和发育阶段差异表达。Csa-miR160d 仅在扩大的黄瓜果实中表达。CsARF 5 、CsARF 11和CsARF 13CsARF 14在膨大果实中的表达低于子房中的表达，而CsARF 14则呈现相反的趋势。我们的研究结果表明，Csa-miR160d 可能通过负靶向CsARF 5 、CsARF 11和CsARF 13在黄瓜果实扩张中发挥关键作用。这是黄瓜中 miR160 的首次全基因组分析。这些发现为进一步研究 miR160 和ARF在黄瓜果实扩张中的作用提供了有用的信息和资源。