Ganoderma lucidum mycelial growth filtrate and the mycelial extract increase defense responses against Septoria leaf spot in tomato

• Foliar application of a Ganoderma lucidum mycelial growth filtrate (MGF) and mycelial extract (ME) reduced more than 90% disease severity of Septoria leaf spot in tomato plant. • MGF and ME increased defense-related enzyme activities in tomato plant. • MGF and ME increase ​antioxidant enzymes, responsible for ROS decomposition, which disarmed the phytopathogen. • These results highlight the possible formulation of a bioproduct derived from G. lucidum for plant disease management. Ganoderma lucidum is a mushroom that produces many compounds with biological activity. The present study aimed to examine the ability of preparations obtained from the mushroom, the mycelial growth filtrate (MGF) and the mycelial extract (ME), to provide protection and induce resistance in tomato against Septoria lycopersici . Under greenhouse conditions, leaf application of MGF and ME at 40 % (v/v) 2 days before fungal inoculation, reduced disease severity and fungus germination by 90 and 60 %, respectively. The metabolism associated with tomato defense was significantly modified in the treated plants, malondialdehyde and hydrogen peroxide levels were reduced, activity of antioxidant enzymes was increased (superoxide dismutase, ascorbate peroxidase and catalase) and secondary plant metabolism was activated through enzyme phenylalanine ammonia-lyase, which resulted in an expressive increase in the phenolic compounds. Therefore, compounds present in MGF and ME activate the defense mechanisms, reduce the oxidative damage caused by Septoria in tomato plants, and promote disease control.