Differential effects of arbuscular mycorrhizal fungi on growth, root rot-associated foliar symptoms, and transcriptomic responses in Lycium barbarum

Abstract

To investigate the effects of different arbuscular mycorrhizal fungi (AMF) on Lycium barbarum under root rot-associated disease stress, Funneliformis mosseae and Rhizophagus intraradices were inoculated into L. barbarum cv. ‘Ningqi 1’ under controlled pot conditions, respectively, followed by infection with Fusarium oxysporum . Plant growth traits, antioxidant and defense-related enzyme activities, and transcriptomic profiles were analyzed to characterize the physiological and molecular responses associated with AMF inoculation under disease stress. AMF-inoculated plants exhibited lower root rot-associated foliar symptom severity, with the disease index decreasing from 45.95 in the pathogen-inoculated control to 13.63–18.67 in the AMF treatments; the calculated control efficacy ranged from 59.37% to 70.35%. Compared to the corresponding control treatment, AMF treatments significantly improved plant growth and root architecture, increasing shoot fresh weight by 1.9 to 4.4 fold and total root length by 82%–124%. Additionally, AMF colonization significantly enhanced antioxidant and defense-related enzyme activities under disease stress, with catalase and superoxide dismutase activities increasing by up to 157% and 130%, respectively. Transcriptome analysis further indicated that AMF symbiosis was associated with differential enrichment of pathways related to plant–pathogen interaction and plant hormone signal transduction under F. oxysporum infection. These findings indicate that different AMF species are associated with reduced root rot-associated foliar symptoms and enhanced growth and defense-related responses in L. barbarum under disease stress, possibly through the modulation of host physiological and molecular responses. This study provides a theoretical basis for further investigation of AMF-based strategies for managing diseases of L. barbarum .