Antagonistic effectiveness of some bacteria against Fusarium graminearum causing crown rot disease on wheat (Triticum aestivum)

Abstract

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.