Phenolic acids and defense-related enzymes in host-pathogen interaction in Senecio aegyptius and the rust fungus, Puccinia lagenophorae

Abstract

The objective of this study was to investigate the effect of the rust fungus Puccinia lagenophorae on total phenols, phenolic acids, and defense-related enzymes in the leaf tissues of the host, Senecio aegyptius. The infection increased the total phenol and defense-related enzymes in the host leaf tissues when compared to healthy tissues. The analysis using HPLC revealed the existence of 10 phenolic acids in healthy and infected host leaves. The infection increased the amounts of caffeic, chlorogenic, ferulic, p-coumaric, and salicylic acids. The examination by TEM revealed the presence of peroxidase activity on the host microbodies, Golgi bodies, endoplasmic reticulum, and the thickening of xylem vessels. After the infection, the activity was localized at the penetration sites of fungal haustoria and in amorphous materials found between the intercellular hyphae and the host cell wall. The heaviest peroxidase activity was detected in heavily infected vascular tissue, due to the monokaryotic infection.