This study aimed to isolate and select endophytic bacterial strains from banana plants with antagonistic activity against Fusarium oxysporum f. sp. cubense TR4 (Foc TR4), the pathogen responsible for Fusarium wilt, and with potential to enhance the growth of banana plants. Twelve endophytic bacterial strains were isolated from different parts of Cavendish bananas collected from several provinces in southern Vietnam. Among them, three isolates exhibited the highest inhibitory effects on Foc TR4 mycelial growth, with inhibition of 78.1% (R-BHDN2.2), 66.71% (R-DPBP1.3), and 61.11% (R-TCTV2.3), respectively. All three isolates demonstrated bioactivities, with maximum values recorded for indole-3-acetic acid (IAA) production (85.49 ± 8.98 µg/mL), siderophore production (94.40 ± 3.98 µg/mL), and phosphate solubilisation (314.45 ± 10.91 µg/mL). Biochemical assays and 16S rDNA sequencing identified the three isolates as Pseudomonas putida R-TCTV2.3, Bacillus amyloliquefaciens R-DPBP1.3, and Bacillus siamensis R-BHDN2.2. In greenhouse experiments, these endophytic strains significantly suppressed Fusarium wilt in the tissue of Cavendish bananas, with the lowest disease incidence (26.7%) and disease index (26%) observed in the treatments compared to 98% and 100%, respectively, in the untreated and Foc TR4 inoculated controls. The highest biocontrol efficacy was achieved at 73.3% (B. siamensis R-BHDN2.2). In addition, these bacterial strains were able to affect the growth of banana plants, such as increasing plant height, stem diameter, and root dry matter. This study demonstrates that endophytic bacteria isolated from Cavendish bananas possess strong biocontrol potential against Fusarium wilt caused by Foc TR4 and promote plant growth.
Tran et al. (Sat,) studied this question.