Approximately 100e120 g of material from each sample were
finely ground using a high-speed knife mill Grindomix GM 200
(Retsch, Germany). Prior to extraction, b-mercaptoethanol (for
5.0 ml of buffer, add 25 mL of b-mercaptoethanol) was added to the
CTAB buffer (1 M Tris HCl pH 8.0; 5 M NaCl; 0.5 M EDTA; 2 g of
CTAB).