S6a
The total amount of DNA in each sample was 500ng as input material for DNA sample preparation.  Sequencing libraries were generated using Hieff NGS MaxUp DNA Library Prep Kit for Illumina (12200ES96,YEASEN,China) following manufacturers instructions and index codes were added to attribute sequences to each sample.  In a nutshell, DNA was broken into fragments of about 500 bp using Covaris 220.  In order to purify DNA fragments of 500 bp, the library fragments were purified with Hieff NGS DNA Selection Beads DNA(12601ES56, YEASEN, China). The purified DNA was end repaired , Adapter Ligated and Fragment selection.  Then PCR was performed with 2 Super CanaceII High-Fidelity Mix,Primer Mix(p5/p7) and Adaptor Ligated DNA .  At last, PCR products were purified (Hieff NGS DNA Selection Beads) and library quality was assessed on the Qubit4.0 Flurometer.  The libraries were then quantified and pooled.  Paired-end sequencing of the library was performed on the NovaSeq 6000 sequencers (Illumina,USA).