Root, 01hr, stress
Brassica napus 3-week-old seedlings were treated with 200mM salt water. Roots were harvested after 1 hour. Total RNA was extracted by Promega SV Total RNA Isolation System.  mRNAs were puriﬁed using oligo(dT)-attached beads and fragmented into small pieces (100–400 bp). The cleaved RNA fragments were then primed with random hexamers and submitted to the synthesis of the ﬁrst-strand and second-strand cDNAs. The synthesized cDNAs were ligated with paired-end adaptors. Then, the cDNA fragments with 200 bp ( 20 bp) size were selected by agarose gel electrophoresis and enriched by PCR ampliﬁcation.