Genome-wide expression profiling of the transcriptomes of four Paulownia tomentosa accessions in response to drought

•We performed the de novo assembly of a transcriptome on of P. tomentosa.•More than 312 million raw transcript reads were assembled into 99,218 unigenes.•Altered expressed genes and pathways induced by drought stress were retrieved.•This study provided a comprehensive map of drought-responsive genes and pathways.

Paulownia tomentosa is an important foundation forest tree species in semiarid areas. The lack of genetic information hinders research into the mechanisms involved in its response to abiotic stresses. Here, short-read sequencing technology (Illumina) was used to de novo assemble the transcriptome on P. tomentosa. A total of 99,218 unigenes with a mean length of 949 nucleotides were assembled. 68,295 unigenes were selected and the functions of their products were predicted using Clusters of Orthologous Groups, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes annotations. Afterwards, hundreds of genes involved in drought response were identified. Twelve putative drought response genes were analyzed by quantitative real-time polymerase chain reaction. This study provides a dataset of genes and inherent biochemical pathways, which will help in understanding the mechanisms of the water-deficit response in P. tomentosa. To our knowledge, this is the first study to highlight the genetic makeup of P. tomentosa.