Transcriptional and post-transcriptional responses of diploid and autotetraploid Paulownia tomentosa × Paulownia fortunei under water-deficit condition

Abstract

To gain insights into the underlying molecular mechanisms of how P. tomentosa (Thunb.) Steud. × P. fortunei (Seem.) Hemsl responds to water-deficit condition at both transcriptional and post-transcriptional levels, we employed mRNA, small RNA and degradome sequencing to identify mRNAs and miRNAs involved in the water-deficit stress response in diploid and autotetraploid P. tomentosa × P. fortunei. Differentially expressed mRNA and miRNA profiles were obtained. The results showed that P. tomentosa × P. fortunei may respond to water-deficit stress through osmotic adjustment, reactive oxygen species (ROS) scavenging and plant hormone signal transduction. Transcription factors (NAC, WRKY, bZIP, ERF, MYB and ZFP) were also involved in the stress response. MiRNAs were found to have a role in P. tomentosa × P. fortunei response to water deficit. This study provides an integral view of the transcriptional and post-transcriptional responses of P. tomentosa × P. fortunei under water-deficit condition. The results will help in better understanding the molecular mechanisms of the water-deficit tolerance in P. tomentosa × P. fortunei, and the candidate water-deficit-responsive genes and miRNAs could be used in genetic engineering for developing Paulownia varieties with enhanced water-deficit tolerance in the future.