Expression of miRNAs in vascular tissue and phloem sap. A. Expression of miRNAs in pumpkin vascular tissue (VT) and phloem sap (PS) detected by miRNA UPL assay. Samples containing 10 ng total RNA isolated from pumpkin vascular bundles and phloem sap each were subjected to stem-loop RT reactions and subsequent UPL qPCR. The PCR was performed in three replicates and miRNA expression was normalized against CmPP16 and expressed as a ratio with vascular tissue miR159 expression, which was set arbitrarily at 1. B. Expression of miRNAs detected by gel blot analyses.