Transcriptional and phytohormone regulatory network involved in LITTLELEAF-mediated organ size development in cucumber (Cucumis sativus)

•Fruit size is an important quality trait of cucumbers. CsLL (littleleaf) gene regulates cucumber organs size which was confirmed by developing near isogenic lines (NIL) of LL gene with marker assisted selection (MAS).•Many transcription factors and phytohormone biosynthesis/signaling pathways related genes are identified and significantly enriched in the comparactive transcriptome analysis.•Auxin and cytokinin played important roles in LL-regulated fruit growth which were identified in RNA-Seq and phytohormone assays.