Cucumber (Cucumis sativus L.) is an agriculturally and economically important vegetable crop worldwide. The thickness of mesocarp is an important quality pertaining to edibility. The development of mesocarp, however, has received little attention. In this study, we selected one thick mesocarp line D8 to analyze the gene expression profiles of mesocarp at 0, 3, 6, and 9 days after pollination (DAP) by RNA sequencing. Genes mainly related to ribosomes, carbon metabolism, biosynthesis of amino acids, and oxidative phosphorylation were up-regulated at 3 DAP. From 3 to 6 DAP, the genes related to oxidative phosphorylation, photosynthesis, and phagosome were highly induced. From 6 to 9 DAP, the genes related to plant hormone signal transduction were highly induced. Differentially expressed genes linked to cyclin, hormone biosynthesis and signaling, carbon metabolism, and transcription factors MYB and WRKY were common up-regulated at 3, 6, 9 DAP in comparison with 0 DAP. The auxin-responsive and cytokinin-responsive genes were significantly up-regulated in mesocarp development. The higher expression levels of the auxin-responsive gene indole-3-acetic acid-amido synthetase 3.6 and the cytokinin response regulator 3/4b in the thick mesocarp cultivar D8 than in the thin mesocarp cultivar XUE1 might have explained the different growth rates of the mesocarp.

黄瓜（Cucumis sativusL.）是世界范围内具有农业和经济意义的重要蔬菜作物。中果皮的厚度是与食用性有关的重要品质。然而，中果皮的发展很少受到关注。在这项研究中，我们选择了一个厚的中果皮品系D8，以通过RNA测序分析授粉后0、3、6和9天的中果皮基因表达谱。在3 DAP时，与核糖体，碳代谢，氨基酸的生物合成和氧化磷酸化有关的基因被上调。从3到6个DAP，与氧化磷酸化，光合作用和吞噬体相关的基因被高度诱导。从6到9 DAP，与植物激素信号转导相关的基因被高度诱导。与细胞周期蛋白，激素生物合成和信号传导，碳代谢，与0 DAP相比，MYB和WRKY通常在3、6、9 DAP上调。生长素应答和细胞分裂素应答基因在中果皮发育中显着上调。生长素应答基因吲哚-3-乙酸-酰胺基合成酶3.6和细胞分裂素应答调节剂3 / 4b在厚中果皮品种D8中的表达水平高于薄中果皮品种XUE1中的表达水平，这可能解释了中果皮品种XUE1的不同生长速率。中果皮。