Arbuscular Mycorrhizal Symbiosis Improves Eggplant Performance and Defense Against Collar Rot Pathogen

Arbuscular mycorrhizal fungi (AMF) are soil-borne microorganisms that form symbiotic relationships with numerous species of terrestrial plants. Suppression of fungal plant diseases and enhanced nutrient uptake are two of the many strategies with which AM fungi may promote plant growth and development. They are crucial in low-input agricultural systems that promote biological aspects over agrochemicals. However, the variability in AM fungal efficiency and the complexity of host-pathogen-AMF interactions pose significant challenges in developing effective biological control strategies. In this regard, a pot trial was conducted with three AM fungal isolates to study their influence on the suppression of collar rot of eggplant. In the in-planta study, AMF inoculation enhanced the activities of defense-related enzymes—PAL, PPO, and POD—while reducing disease incidence, with the UASDAMF consortium showing the most substantial reduction (28.33%). The AM fungi significantly reduced collar rot incidence through strong antagonistic activity against S. rolfsii. The plants treated with UASDAMF consortium demonstrated 32% improvement in shoot growth, 142% increase in yield over the control. The AM fungal species effectively enhanced plant nutrient content, specifically 100% increase in P content. Soil enzyme activities were found to be highest with 19% increase in the UASDAMF consortium at 90 DAT. This study contributes valuable insights into the application of native AM fungal consortia as a sustainable alternative to chemical controls in managing soil-borne diseases and improving crop productivity.