Project description:Purpose: The goals of this study was to obtain transcriptome data from five developmental stages of adventitious roots of Pyrus ussuriensis Maxim using transcriptome analysis (RNA-Seq) and qRT-PCR analysis. Mathods: The mRNA profiles of the adventitious root development of Pyrus ussuriensis on day 0, day 3, day 6, day 9, and day 12 were examined by deep sequencing, in triplicate, using Illumina HiSeq 2000. Ultra™ RNA LibraryPrep Kit for Illumina® (NEB, USA) following manufacturer’s recommendations and indexcodes were added to attribute sequences to each sample. qRT–PCR validation was performed using TaqMan and SYBR Green assays. Results: The transcriptome regulation analysis of the Pyrus ussuriensis adventitious root formation was performed on this study. And a total of 19,470 DEGs (Differentially Expressed Gene), which were mainly enriched in hormone synthesis and signaling pathways, energy metabolism, synthesis and metabolism of secondary products, were detected. the key regulatory genes of adventitious root formation were screened, mainly including the gene family WOX, LBD and SRS. Auxin, plays a key role in the induction and development of root primordium, its signal transduction pathway-related genes were up-regulated during the induction period of root primordium, and down-regulated during the development of root primordia. Carotenoids is the precursor substance of abscisic acid synthetize. And for the reasons that the genes of carotenoid synthesis and signal transduction pathway of abscisic acid were down-regulated during the period of stable development and the root primordium induction, and up-regulated during the period of root primordium development of adventitious root, it was supposed that abscisic acid was a control substance, that regulated the metabolic network of development of adventitious roots. Conclusions: Our results provide a comprehensive high-resolution characterization of gene expression profiles during the pear root transition process.A number of DEGs were detected from the root primordium to adventitious root growth stages, and these belonged to hormone metabolism pathways.These results provide a valuable resource for studies in other closely related species with similar agricultural and productive value. The differentially expressed genes dataset will also provide useful candidate genes for functional analysis of pear rooting.