Evaluation of Inhibition Efficiency of Some Bacteria Isolated from Greenhouse Soils on the Growth of the Pathogenic Fungus Sclerotinia sclerotiorum that Causes White Rot Disease on Vegetables in the Laboratory

Al-Kubaisy, A.K.A. and H.H. Al-Juboor. 2022. Evaluation of Inhibition Efficiency of Some Bacteria Isolated from Greenhouse Soils on the Growth of the Pathogenic Fungus Sclerotinia sclerotiorum that Causes White Rot Disease on Vegetables in the Laboratory. Arab Journal of Plant Protection, 40(2): 140-147. https://doi.org/10.22268/AJPP-40.2.140147 This study aimed to isolate beneficial bacteria from the soil of plastic houses planted with eggplant and cucumber at different locations of Baghdad Governorate and characterize them molecularly in addition to determining their antagonistic ability to inhibit six isolates of the pathogenic fungus Sclerotinia sclerotiorum, the causal agent of white rot disease. The isolation results showed that 18 different bacterial isolates were obtained from several fields in Baghdad governorate. Bacterial isolates showed antagonistic ability towards six isolates of the pathogenic fungus S. sclerotiorum (ScE1, ScE2, ScE3, ScE4, ScC1 and ScC2), and the inhibition rate ranged between 84.25 and 93.75%. The two bacterial isolates BE1 and BE6 excelled in plastic houses grown with eggplant plants, and the inhibition rate of the fungal pathogen reached 93.75%. Whereas, the bacterial isolate BC9 isolated from soils planted with cucumber plants achieved the highest inhibition rate of all fungal isolates, except isolate ScE1, which reached 84.25%. Bacterial isolates were identified molecularly and they were registered in the GenBank under accession numbers MZ436922, MZ436923, MZ436921 and MZ436920 for the isolates of Alcaligenes faecalis, Bacillus amyloliquefaciens, Bacillus subtilis and Pseudomonas aeruginosa, respectively. Keywords: Sclerotinia sclerotiorum, biological control, molecular identification, eggplant