design: After DNA extraction and amplification, the amplicon quality was                 visualized via gel electrophoresis. The PCR products were purified with Agencourt                 AMPure XP beads (Beckman Coulter Co., USA) and quantified via a Qubit dsDNA assay                 kit. The concentrations were then adjusted for sequencing. Sequencing was performed                 on an Illumina NovaSeq 6000 with two paired-end read cycles of 329 bases each.                 (Illumina Inc., San Diego, CA; OE Biotech Company; Shanghai,                 China).