Restricted O2 consumption in pea roots induced by hexanoic acid is linked to depletion of Krebs cycle substrates

• DOI: 10.1111/ppl.14024
• Publication Date: 2023-09-21T08:55:39Z
• Authors: Valentino Casolo; Marco Zancani; Elisa Pellegrini; Antonio Filippi; Sara Gargiulo; Dennis Konnerup; Piero Morandini; Ole Pedersen
• Keywords: Hexanoic acid; Efflux; Organic acid; Diad

Abstract Plant roots are exposed to hypoxia in waterlogged soils, and they further challenged by specific phytotoxins produced microorganisms such conditions. One toxin is hexanoic acid (HxA), which, at toxic levels, causes a strong decline root O 2 consumption. However, the mechanism underlying this process still unknown. We treated pea ( Pisum sativum L.) with 20 mM HxA pH 5.0 6.0 for short time (1 h) measured leakage of key electrolytes as metal cations, malate, citrate nonstructural carbohydrates (NSC). After treatment, mitochondria were isolated assess their functionality evaluated electrical potential consumption rate. treatment resulted tissue extrusion K + , NSC, but only organic acids NSC increased 5.0, concomitantly inhibition The activity from was almost unaffected, showing just slight decrease oxygen after 5.0. Similar results obtained treating another carbon chain, that is, butyric acid. Based on these results, we propose model which HxA, its undissociated form prevalent acidic pH, stimulates efflux citrate, malate would, turn, cause starvation mitochondrial respiratory substrates Krebs cycle consequent Cation would be compensatory order restore plasma membrane potential.