Mycorrhizal symbiosis and application of vitamin B3-treated Trichoderma Harzianum HE24 additively trigger immunity responses in faba bean plants against Rhizoctonia root rot and promote the plant growth and yield.

Background: Faba bean is a valuable legume crop, known for its high nutritional value and nitrogen fixing ability. Rhizoctonia root rot of faba bean, caused by , severely affects the plant growth and yield. This study aimed to evaluate the effect of symbiosis with arbuscular mycorrhizal fungi (AMF) and application of vitamin B3-treated HE24 on plant immune responses against Rhizoctonia root rot under greenhouse conditions.