Symbiosis of Soil Inhibiting Beneficial Microbes Boosts Immunity to Root Rot and Foot Rot of Betelvine with Enhanced Productivity

Abstract

Betelvine (Piper betle L.) is an important cash crop grown primarily for its leaves, which are used in culinary, medicinal, and cultural practices. However, the yield of the culinary herb is greatly challenged by various pathogens, especially Sclerotium rolfsii. To reduce the target pathogen load, our study investigated the field efficiency of some selective soil-inhabiting beneficial microbes—Trichoderma harzianum (Th), Pseudomonas fluorescens (Pf), and Arbuscular Mycorrhizal Fungi (AMF)—on the growth and yield, metabolite profiling and immune response of the betelvine to S. rolfsii. The treatments were applied individually and in combination following RCBD design with triplicates. Results indicated that the combined application of Th, Pf, and AMF significantly enhanced nitrogen, phosphorus, and potassium accumulation which positively improved plant growth, yielding the highest values for vine length (142.77±2.75 cm), number of laterals (22.00±1.15), and leaf breadth (13.70±0.75 cm). Yield parameters such as100-leaf weight (277.23 ±2.98g), leaf number per plant (82.00±1.57) as well as income (182.25 ±1.72 taka per plant) were also statistically higher in the combined treatment compared to untreated controls and individual treatments. The disease incidence reduced by up to 74.32% in plants treated with Th + Pf + AMF. Biochemical analysis showed significant increases in flavonoids (Kaempferol 19.46 μg/g±0.42 mg/g), tannins (Catechuic acid 15.14±0.33 mg/g), and phenolic acids (Gallic acid 12.50±0.26 mg/g) in plants treated with the Th + Pf + AMF compared to check. In molecular docking analysis of eight bioactive ligands with the 1J58 (Oxalate Decarboxylase) and 1BHE (Polygalacturonase) proteins identified strong binding interactions, with Catechuic acid exhibiting the highest number of interactions with 1J58, and Quercetin demonstrating the broadest interaction profile with 1BHE, highlighting their potential in mitigating disease by effectively targeting these proteins through specific molecular binding. These findings suggest that the combination of these microbial treatments can effectively boost betelvine productivity by enhancing host immunity and concentration of bioactive compounds, offering a sustainable ecoefficient alternative to traditional chemical control of foot and root rot of betelvine.