Controlling Tomato Fusarium Wilt Disease through Bacillus thuringiensis-Mediated Defense Primining

Background: Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. lycopersici (Fol) (Sacc.) W.C. Snyder andH.N. Hans is one of the most prevalent and devastating diseases of tomato plants (Solanum lycoprsicum L.) that leads toa severe reduction in crop yield almost worldwide Objective: Evaluation of biocontrol potential of Bacillus thuringiensis (Bt) isolate IBRC-M11096, against Fol in tomatothrough priming. Materials and Methods:  qRT-PCR technique was applied to analyze the effect of the strain on the hormonal defensivepathways; transcriptional responses of jasmonic acid (COI1, Pin2) and salicylic acid (NRP1 and PR1) pathway genes inBt-treated plants following inoculation of Fol as compared to the plants only challenged with Fol. Also, the potential ofthe bacterial strain as a biocontrol agent was studied by evaluating growth indices and area under disease progress curve(AUDPC). Results: The transcription of both defensive hormonal pathway genes (COI1, Pin2, NPR1, PR1) increased due to bacterialpriming. The bacterial priming reduced the AUDPC compared to the inoculation with only Fol. The strain reduced thedisease symptoms, and compared to the plants only challenged with the fungus, the bacterial strain significantly raisedshoot dry and fresh weights and root dry weight. Conclusions: Priming with the Bt strain led to improved shoot and root growth indices, reduced AUDPC, and fortifiedresponses of both JA and SA hormonal pathways. However, further full-span studies are required to judge the efficacy ofthe bacterial strain in the biological control of tomato fusarium wilt under field conditions.