Study of the role of oat beta-1,3-glucanases and chitinases in the defence against Blumeria graminis, cadmium and their combinations

Abstract In this study, we evaluate the mechanisms of oat tolerance under various stress conditions. Five oat varieties were exposed to cadmium ions (Cd²⁺, 50 mg kg − 1 soil) after 22 days of cultivation in soil substrate, and to Blumeria graminis after 33 days. Simultaneously, the response of oats to both stressors was assessed (variant P + Cd) in the context of changes in the activity of β-1,3-glucanases and chitinases. Overall, we detected six isoforms of total β-1,3-glucanases (35–140 kDa) and six total chitinases (23–260 kDa) on polyacrylamide gels. The increased activity of most isoforms (total, acidic, and basic) of these enzymes in infected leaves confirms their major role in defence against the pathogen, and we also recorded de novo accumulation of some isoforms. Changes in their activity were dependent on genotype, experimental variant, and isoform. Some isoforms of β-1,3-glucanases and chitinases were also Cd-responsive. The reduced activity of certain β-1,3-glucanase isoforms (48 kDa) suggests their involvement in other defence mechanisms, likely related to the synthesis or degradation of other polysaccharides. The metal’s protective effect was not clearly confirmed in the context of the response to powdery mildew. Metal content in tissues did not correlate with the activity of β-1,3-glucanases and chitinases in any metal variant of the experiment.