Effect of different bacterial treatment strategies on the damping-off disease control in cotton seedlings

Bacillus halotolerans, that was isolated from Gossypium barbadense and molecularly identified using 16S rRNA gene sequencing analysis, was tested for its antifungal potential in cotton seedlings infected with the phytopathogenic fungus Rhizoctonia solani. The antifungal activity of the rhizobacterial strain was studied under greenhouse conditions. In soil contaminated with R. solani, the bacterial strain was applied in three replicates as a seed presoaking, seed coating, or soil drench. Evaluating their efficacy based on plant growth and disease suppression. According to our findings, seed coating and the soil drench treatments were more effective than the seed presoaking. Significant improvements in seed emergence, 26, 34, and 40 % increase for seed presoaking, soil drench, and seed coating. Comparing the treated plants to the uninoculated ones, the fresh and dry weights of the soil drench group increased significantly by 21.6 and 23.4%, respectively. While 45.1 and 33.7% for seed presoaking group. Also 51.3 and 47.87% for seed coating group. Furthermore, it appeared that the treated seedlings' levels of the enzymatic and non-enzymatic antioxidants, glutathione reductase, superoxide dismutase, ascorbate peroxidase, catalase, glutathione, and ascorbic acid were positively inducted specifically for seed presoaking group. The total protein and carbohydrate contents of the different treatments varied greatly with the highest levels in the soil drench group. While the highest levels of total phosphorus and chlorophyll_a were observed in the seed coating group. GC-MS analysis showed that the bacterial supernatant included a number of antifungal bioactive compounds, including di-ethyl phthalate and 2,4-di-tertbutyl phenol.