Phenotypic and visual analysis of tomato plant infected by Pseudomonas Cichorii for detection and quantification of disease severity

Abstract

Pathogen infection in plants induces complex responses from gene expressions to Metabolic processes in the infected plants. In spite of many studies on changes in host plants by pathogens, little is known about the Metabolic and Phenotypic alterations of the host plants to P. Cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated tomato plants with different cell densities of P. Cichorii using dipping and syringe infiltration methods. High-dose Inoculums (≥106 cfu/ml) induced visible necrotic lesions within one day, which corresponds to internal bacterial growth in the infected tissues. Among the chlorophyll fluorescence (ChF) parameters that analyzed in this study, changes in OPSII and NP Q preceded the appearance of visible symptoms, but Fv/Fm was altered after symptom development. VIS/NIR and ChF hyperspectral images visualized changes before visible symptom appearance at low-density inoculation. The results of this study suggest that the P. Cichorii infection and its severity can be detected by ChF assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection y of diseases. However, to detect and evaluate disease development by hyperspectral imaging, more detailed protocols and analyses need to be developed. Overall, the results of this study indicate that change in ChF is a good parameter for early detection of P. Cichorii infection in tomato plants. Furthermore, image-based visualization of infection severity before visual damage appearance will contribute to effective management of Plant Diseases.