Restricted O 2 consumption in pea roots induced by hexanoic acid is linked to depletion of Krebs cycle substrates.

Autor: Casolo V; Plant Biology Laboratory, Department of Agrifood, Environmental and Animal Sciences, University of Udine, Udine, Italy., Zancani M; Plant Biology Laboratory, Department of Agrifood, Environmental and Animal Sciences, University of Udine, Udine, Italy., Pellegrini E; Plant Biology Laboratory, Department of Agrifood, Environmental and Animal Sciences, University of Udine, Udine, Italy.; Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark., Filippi A; Plant Biology Laboratory, Department of Agrifood, Environmental and Animal Sciences, University of Udine, Udine, Italy.; Department of Medicine, University of Udine, Udine, Italy., Gargiulo S; Plant Biology Laboratory, Department of Agrifood, Environmental and Animal Sciences, University of Udine, Udine, Italy.; Department of Life Sciences, University of Trieste, Trieste, Italy., Konnerup D; Department of Food Science, Aarhus University, Aarhus, Denmark., Morandini P; Department of Environmental Science and Policy, University of Milan, Milano, Italy., Pedersen O; Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.; School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia.
Jazyk: angličtina
Zdroj: Physiologia plantarum [Physiol Plant] 2023 Sep-Oct; Vol. 175 (5), pp. e14024.
DOI: 10.1111/ppl.14024
Abstrakt: Plant roots are exposed to hypoxia in waterlogged soils, and they are further challenged by specific phytotoxins produced by microorganisms in such conditions. One such toxin is hexanoic acid (HxA), which, at toxic levels, causes a strong decline in root O 2 consumption. However, the mechanism underlying this process is still unknown. We treated pea (Pisum sativum L.) roots with 20 mM HxA at pH 5.0 and 6.0 for a short time (1 h) and measured leakage of key electrolytes such as metal cations, malate, citrate and nonstructural carbohydrates (NSC). After treatment, mitochondria were isolated to assess their functionality evaluated as electrical potential and O 2 consumption rate. HxA treatment resulted in root tissue extrusion of K + , malate, citrate and NSC, but only the leakage of the organic acids and NSC increased at pH 5.0, concomitantly with the inhibition of O 2 consumption. The activity of mitochondria isolated from treated roots was almost unaffected, showing just a slight decrease in oxygen consumption after treatment at pH 5.0. Similar results were obtained by treating the pea roots with another organic acid with a short carbon chain, that is, butyric acid. Based on these results, we propose a model in which HxA, in its undissociated form prevalent at acidic pH, stimulates the efflux of citrate, malate and NSC, which would, in turn, cause starvation of mitochondrial respiratory substrates of the Krebs cycle and a consequent decline in O 2 consumption. Cation extrusion would be a compensatory mechanism in order to restore plasma membrane potential.
(© 2023 The Authors. Physiologia Plantarum published by John Wiley & Sons Ltd on behalf of Scandinavian Plant Physiology Society.)
Databáze: MEDLINE
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