Physiological and biochemical characterization of a susceptible carnation (Dianthus caryophyllus L.) cultivar to Fusarium oxysporum f. sp. dianthi (Fod)

Abstract

The susceptibility of carnations (Dianthus caryophyllus L.) to infection by Fusarium oxysporum f. sp. dianthi (Fod) poses a significant challenge to agricultural production, particularly in Colombia, a country that is a global leader in carnation exportation. This study focused on the physiological and biochemical responses of a highly susceptible carnation cultivar ‘Solex’, to the presence of Fod to better understand the underlying mechanisms of susceptibility and to enhance early disease detection strategies in carnation crops. At the biochemical level, we analyzed the content of phenolic compounds and flavonoids in roots and stems; and we assessed physiological parameters such as foliar photosynthetic pigment content, stomatal resistance, maximum photochemical efficiency of PSII (Fv/Fm) and leaf temperature. Our research unveiled a marked decrease in metabolite production in the roots of carnation plants inoculated with Fod that was particularly evident at 4 post-inoculation days. Furthermore, we observed an early increase in leaf temperature from 1 post-inoculation day onwards, without changes in stomatal closure dynamics over time. Additionally, we recorded a significative decline in Fv/Fm, photosynthetic pigment content and dry biomass production in Fod-inoculated plants during the symptomatic phase of vascular wilting that contrasted starkly with pathogen-free controls. These findings underscored the intrinsic susceptibility of carnation plants to Fod infection, with significant implications for enhancing plant resistance and developing effective vascular wilting management strategies in crops of this flower.