Differential Responses of Root Rot Pathogen Rhizoctonia solani in Tolerant and Susceptible Varieties of Tomato at Various Physiological Levels

Introduction: This study investigates the defense responses of tolerant versus susceptible varieties of tomato against the hemi biotroph pathogen Rhizoctonia solani. Method: The early infection of Rhizoctonia solani was characterized by a tolerant Pusa Ruby and a susceptible tomato variety, Oriental (VT- 946). Result: The microscopy experiments showed more hyphal growth in a susceptible plant than in a tolerant one. The hyphae formed extensive branching, contacting the host surface to form a greater number of various infection structures for penetration in the susceptible host compared to the tolerant variety. Biochemical assays showed differences in the production of phenolics, proline, hydrogen peroxide, and catalase in the tomato varieties. Conclusion: The differential expression profiles of the early response allene oxide synthase AOS gene were obtained over time in the two hosts.