Analysis of some fatty acids and genes against root rot (Phytophthora capsici Leonian) in pepper (Capsicum annum L.)

In this thesis, root, stem and leaf tissues were harvested from two pepper cultivars (CM334 ((Criollos de Morelos 334)) susceptible (local cultivar) and resistant (CM334 ((Criollos de Morelos 334)) to root-knot disease at 6 and 24 hours after pathogen application. In these harvested tissues, the lipid homeostasis established by the pepper plant at the cellular level to create resistance against the pathogen was investigated. In addition, in order to analyze the changing expression levels of many genes involved in lipid biosynthesis in the cell, the expression profiles of the relevant genes were examined on a tissue basis by PCR (Polymerase Chain Reaction). In this study, the gene regulatory mechanisms involved in resistance to this pathogen and the functions of lipids as biological agents were examined by using materials whose resistance to this pathogen was previously determined by classical studies and sampling at different time intervals. As a result of this study, it was observed that fatty acid and fatty acid genes have many roles in the resistance of pepper plants against the P. capsici pathogen. In this study, among the five genes examined, the highest relative expression value was found in the FAD1 gene in the leaf tissue of the CM334 variety taken 24 hours after the pathogen application, and the lowest value was found in the FAT gene in the root control tissue of the Demre variety taken 24 hours after the application. As in most plants, the most abundant fatty acids in pepper leaves were oleic (18:1n-9) and linoleic (18:2n-6) acids. Both CM334 and Sera Demre cultivars showed an increase in total fatty acid amounts in the 24 h treatment compared to the control groups.