dU-adaptor-assembled Tn5-mediated strand-specific RNA-sequencing.

Strand-specific RNA-seq is a powerful tool for discovery of novel transcripts, annotation of genomes, and profiling of gene expression levels. Tn5 transposase has been successfully applied in massive-scale sequencing projects; in particular, Tn5 adaptor modification is used in epigenetics, genomic structure, and chromatin visualization. We developed a novel dU-adaptor-assembled Tn5-mediated strand-specific RNA-sequencing protocol and compared this method with the leading dUTP method in terms of experimental procedure and multiple quality metrics of the generated libraries. The results showed the dU-Tn5 method is easy to operate and generates a strand-specific RNA-seq library of comparable quality considering library complexity, strand-specificity, evenness, and continuity of annotated transcript coverage. We also evaluated the performance of the dU-Tn5 method in identifying nitrogen-responsive protein-coding genes and long non-coding RNAs in soybean roots. The results indicated that ~62-70% of differentially expressed genes (DEGs) detected from conventional libraries were also detected in dU-Tn5 libraries, indicating good agreement of our method with the current standard; moreover, their fold-changes were highly correlated (R > 0.9). Thus, our method provides a promising "do-it-yourself" stranded RNA-seq procedure for gene expression profiling.