title: AtXRN4 affects the turnover of plant small RNAs
design: sRNA isolation and library construction was performed as described before. Briefly, four-week-old plants were collected and RNA was isolated with TRIzol Reagent (Invitrogen) according to manufacturers instructions. Approximately 1g rosette leaves were ground in liquid nitrogen and mixed with 10ml TRIzol Reagent for RNA isolation. Supernatant was mixed with 2.2 fold volume ethanol and put at -20C overnight. The concentration and quality of isolated RNA were determined by NanoDrop spectrophotometer (Thermo Scientific) and gel electrophoresis, respectively. 20ug total RNA was used for sRNA library construction with Illumina Truseq sRNA library preparation kit (Illumina).