Fastprep 24tm homogeniser

Freeze dried stems were cut into small pieces with scissors and weighed. They were milled by adding ∼0.2 ml Lysing matrix D Bulk (MP Biomedicals, United States) to each sample tube and mechanically shaking them in a FastPrep-24^TM homogeniser (MP Biomedicals, United States). DNA was extracted using the method described by Ray et al. (2004) (link) adjusting the amount of CTAB (15 ml for 2 g of plant sample) to the weight of the sample.

Fungal DNA from compost was extracted using a modified version of Sturrock et al. (2015) (link). Compost from two biological replicate plants were combined into one sample (2 g) for each treatment of each variety. For homogenization, each sample was placed in a 50 ml falcon tube with three 1/4 inch ceramic balls (MP Biomedicals, United States), 15 ml of CTAB buffer (cetyltrimethylammonium bromide) and 0.45 ml of Antifoam B and homogenized using a FastPrep-24^TM homogeniser (MP Biomedicals, United States). DNA extraction was performed using the Wizard Magnetic DNA Purification System for Food as per manufacturer’s instructions (Promega Wizard Food Kit, Southampton, United Kingdom).