Endophyte profiling of tomato leaf curl virus (ToLCV) resistant and susceptible tomato genotypes: Insights into microbial diversity and growth promotion

Tomato (Solanum lycopersicum L.) is one of the most widely cultivated vegetable crops globally. Still, its productivity is significantly constrained by tomato leaf curl virus (ToLCV), a devastating begomovirus transmitted by whiteflies. This study examined the diversity and plant growth-promoting potential of culturable endophytes associated with tomato cultivars differing in resistance to tomato leaf curl virus (ToLCV). A total of 59 fungal and bacterial endophytes were isolated. Resistant cultivars (Nandi, Sankranthi, and Vybhav) harboured more diverse and compositionally distinct communities than the susceptible cultivar Arka Vikas, as indicated by Shannon, Simpson, and Chao-1 indices and multivariate analyses. Several isolates, particularly from the genera Xylaria, Fusarium, Arcopilus, Epicoccum, Bacillus, Pseudomonas, Stutzerimonas, and Paenibacillus, displayed strong nutrient-solubilizing traits in vitro, highlighting their potential as plant growth-promoting candidates. Eleven promising isolates were further evaluated on the susceptible cultivar Arka Vikas. At 30 days after sowing, Epicoccum nigrum and Bacillus subtilis significantly increased seedling height, biomass, and leaf number relative to the control. Overall, the study reveals that resistant cultivars are associated with greater culturable endophyte diversity and identifies several isolates with strong potential for promoting plant growth. Future research should assess the antiviral potential of these endophytes under ToLCV challenge and employ metagenomic studies to elucidate their functional roles in enhancing plant health.