Preliminary Molecular Identification of a Pantoea stewartii-Related Isolate Associated with Sorghum Leaf Blight in the Jazan Region of Saudi Arabia and Its in vitro Response to Solanum incanum L. Extract

Background. Sorghum (Sorghum bicolor L.) is an important cereal crop cultivated in arid and semi-arid regions, including southwestern Saudi Arabia, where bacterial diseases may threaten crop productivity and sustainability.Objective. This study aimed to characterize a bacterial isolate associated with sorghum leaf blight symptoms in the Jazan region of Saudi Arabia and to evaluate the in vitro antibacterial activity of Solanum incanum L. methanolic extract against the recovered isolate.Methodology. Sorghum plants exhibiting leaf blight and water-soaked lesions were sampled for bacterial isolation. A representative bacterial isolate recovered from symptomatic tissues was characterized using morphological observations and 16S rRNA gene sequencing. Phylogenetic analysis was conducted using reference sequences available in GenBank. The antibacterial activity of methanolic extracts of S. incanum L. was assessed in vitro using the agar well diffusion method at concentrations of 2.5, 5, and 10 μg/mL. Statistical analyses were performed to evaluate differences among treatments.Results. Sequence analysis indicated close similarity between the recovered isolate and Pantoea stewartii. Phylogenetic analysis grouped the isolate with reference strains of P. stewartii. available in GenBank. The methanolic extract of S. incanum L. exhibited concentration-dependent antibacterial activity against the tested isolate, with inhibition zones ranging from 11 to 15 mm. Statistical analysis revealed significant differences among treatments (p < 0.001).Conclusion. Although the findings are preliminary and based on a single isolate and in vitro assays, the results suggest that S. incanum L. possesses antibacterial activity against the tested bacterium. Further molecular characterization, pathogenicity studies, and field-based investigations are required to confirm the pathogenic role of the isolate and to evaluate the practical applicability of S. incanum L. extracts under agricultural conditions.