Evaluation of the Antagonistic Effect of Pseudomonas Rhizobacteria on Fusarium Wilt of Chickpea

This study aimed to isolate rhizobacteria belonging to the genus Pseudomonas with plant-growth-promoting properties that can be used in the control of chickpea wilt disease caused by Fusarium oxysporum f. sp. ciceris (Foc). The production of antifungal compounds by the isolated rhizobacteria was assessed against two Foc isolates, coded Foc-S1 and Foc-S2. Strains E1FP13, E1FP4, and E1PP7 were the most effective against Foc-S1, with percentages of 52.77%, 48.37%, and 47.97%, respectively, while E1PP6, E1FP13, and E1PP15 were the most effective against Foc-S2 with percentages of 52.20%, 52.09%, and 45.38%, respectively. All five isolates were identified as Pseudomonas species using 16S rRNA sequencing. The microscopic examination of the impact of the Pseudomonas strains on Foc revealed that all five strains caused morphological changes in Foc, such as granulation and condensation of the cytoplasm, fragmentation, and deformation of the hyphae. The strains produced several plant-growth-promoting compounds, such as cellulase, hydrogen cyanide, indole acetic acid, ammonia, siderophores, lipase, protease, and solubilized phosphate. They were also able to significantly increase chickpea growth and reduce wilt disease, with E1FP13 resulting in the highest disease reductions of 55.77% (Foc-S1) and 53.33% (Foc-S2). The results revealed that our isolates can make promising biocontrol agents for controlling chickpea wilt disease.