Nanodrop spectrometer nd 1000 spectrophotometer

Total RNA was isolated from the roots with the RNeasy Plant mini kit (Qiagen, Cat#:74904) following the manufacturer’s protocols. On-column DNase digestion with the RNase-Free DNase set were used to remove the DNA contamination (Qiagen, Valencia, CA, Cat#:79254). The RNA quantity was checked with a NanoDrop Spectrometer (ND-1000 Spectrophotometer, Thermo Scientific). The RNA integrity was analyzed using the Agilent 2100 Bioanalyzer (RNA Nano Chip, Agilent, Santa Clara, CA, USA). The RNA integrity number value ≥7 was used to select the best RNA for library construction. Total RNA, 2 μg from each sample, was used for library construction. The RNA TruSeq Stranded mRNA LT sample prep kit (Illumina, San Diego, CA, RS-122-2101) was used to prepare the RNA-Seq library following the manufacturer’s protocols. A Qubit quantitation assay and the NGS Fragment Analysis (Agilent 2100 Bioanalyzer, Santa Clara, CA) were conducted on each library. Single end reads were generated by the Illumina HiSeq 2000 (read length 1 × 100 base; Illumina, Inc. San Diego, CA).

All samples were collected from plants growing in the experimental fields at Jilin Agricultural University, Changchun, China. Cetyltrimethylammonium bromide (CTAB) technique (slightly modified), as described by Murray and Thompson (1980) (link) was used for DNA extraction from young and healthy leaves of each soybean accession. NanoDrop Spectrometer (ND-1000 Spectrophotometer, Thermo Scientific) was used to determine the DNA concentration and consistency of all samples. For SLAF sequencing, the quantified DNA was diluted to 100 ng⋅μl-1.