Isolated endophytic bacteria promoted growth, essential oil content, and antioxidant activity in Basil (Ocimum basilicum L.)

Basil (Ocimum basilicum L.), a medicinal plant and edible vegetable from the Lamiaceae family, holds significant therapeutic and culinary value. Endophytic bacterial inoculation is an effective strategy for enhancing the essential oil content and metabolic profile of medicinal plants. This study isolated and molecularly identified two endophytic bacteria, and evaluated their effects on the physiological, biochemical, and essential oil traits of basil using a completely randomized design. The bacterial isolates were identified as Microbacterium foliorum Emf1 and Paenibacillus peoriae ER11. Both isolates significantly improved key growth traits, with M. foliorum Emf1 showing the most substantial impact across various indicators. Notable increases compared to the control included root volume (106.79%), root surface area (60.66%), root fresh (71.81%) and dry weight (77.77%), shoot fresh (81.73%) and dry weight (81.48%), leaf fresh (84.54%) and dry weight (83.59%), membrane stability (400.85%), carotenoid content (200.00%), anthocyanin levels (61.90%), essential oil content (101.43%), total phenol (20.46%), and antioxidant activity (56.6%). This research provides novel insights by demonstrating the beneficial effects of these two endophytic bacterial isolates in enhancing basil's growth performance, biochemical properties and essential oil content.