Metabarcoding of ch5 sample
For fungal community analysis, the ITS2 region of the ribosomal DNA was targeted using the primers ITS3-2024F (GCATCGATGAAGAACGCAGC) and ITS4-2409R (TCCTCCGCTTATTGATATGC), producing an amplified fragment of approximately 380 base pairs. To reduce PCR bias and ensure adequate DNA yield, duplicate amplifications were performed and combined in equal proportions. Sequencing libraries were constructed using the Illumina TruSeq DNA PCR-Free Library Preparation Kit (Illumina, San Diego, CA, USA), following the manufacturers recommendations. Library integrity was verified using a Qubit 2.0 Fluorometer (Thermo Scientific, Waltham, MA, USA), and sequencing was subsequently conducted on the Illumina NovaSeq 6000 system, employing a 250 bp paired-end configuration according to standard protocols.