(Biocontrol of Tomato Early Blight Disease Using Some Endophytic Bacterial and Fungal Isolates)

Abo Zaid, Omyma A.A; Mahmoud, Mostafa H.A.; Asran, Mahmoud R.

doi:10.21608/jsasj.2025.461886

(Biocontrol of Tomato Early Blight Disease Using Some Endophytic Bacterial and Fungal Isolates)

Document Type : Research and Review Papers

Authors

Plant Pathology Department Faculty of Agriculture Sohag University Sohag Egypt

10.21608/jsasj.2025.461886

Abstract

Early blight (EB) disease of tomatoes, caused by Alternaria solani, is one of the most common and devastating diseases, primarily affecting the plant foliage, stems, and fruits, resulting in severe defoliation, decreased yield, and compromised fruit quality. The current study investigated the potential impact of using endophytic bacterial and fungal isolates for EB disease management and plant growth enhancement. Ten endophytic bacterial and fungal isolates were obtained from the stems and leaves of tomato plants collected from various locations in the Sohag Governorate. These isolates were identified as Bacillus atrophaeus, B. subtilis, Pseudomonas corrugata, Ps. florsenses, Aspergillus nidulans, A. terreus, Penicillium crustosum, Trichoderma hamatum, T. harzianum, and T. koningii. During in vitro testing, the isolates showed varying levels of antagonistic activity against A. solani. All isolates reduced the mycelial radial growth (MRG) of A. solani, with T. harzianum exhibiting the highest reduction of MRG at 7.4 cm and 82.22% followed by B. subtilis and T. koningii. In contrast, P. crustosum and Ps. corrugata showed the lowest reduction of MRG at (1.1 cm and 12.22%) and (1.2 cm and 13.33%), respectively. In the greenhouse and field trails during the 2021 and 2022 growing seasons, the four selected isolates were effective and controlled tomato EB disease, resulting in a decreased percent disease index (PDI) compared to the control. T. harzianum and B. subtilis were the most effective, showing the highest reduction in PDI and improved plant height, shoot fresh, and dry weight, followed by T. koningii. Biochemical analysis of tomato plants after 2, 4, 8, and 16 days of inoculating with A. solani revealed that plants inoculated with the selected endophytic bacterial and fungal isolates, especially T. harzianum and B. subtilis, exhibited the highest increase in total protein content, peroxidase, and polyphenol oxidase activity, and total phenolic content, followed by T. koningii. In conclusion, these endophytes have shown potential in managing EB disease, enhancing plant growth, and improving biochemical attributes to combat EB stress in tomato plants.

Keywords