Comprehensive Plant DNA Extraction and Sequencing

Total DNA was extracted from dried leaf tissue using a CTAB method [13 ]. The amplification of rbcL, matK, trnH-psbA, ITS and ITS2 was carried out with universal primer sets ([14 (link)–19 (link)], Table 1). We amplified DNA in a 25 μL reaction mixture following Zhang et al. [20 (link)] using rTaq DNA polymerase. For those samples that failed to amplify on a first pass, LA or Primer Star DNA polymerase (Takara Biotechnology Co. Ltd.) or 2*T5 Super PCR Mix (Beijing TsingKe Biotech Co., Ltd.) was used as an alternative to rTaq DNA polymerase. Samples showing a clear single band were sent to Shanghai Majorbio Bio-Pharm Technology Co., Ltd., Shanghai, China for bi-directional sequencing. All sequences were uploaded to the GenBank (GenBank accession numbers are given in S1 Table).