Phytohormone Profiling of Malus domestica and Chenopodium murale Hairy Root Exudate: Association with Allelopathic Effects

Ninković S., Motyka V., Stanišić M., Smailagić D., Živanović B., Dobrev P.I., Banjac N.
JOURNAL OF PLANT GROWTH REGULATION 43: 3580–3593, 2024

Keywords: Allelopathy, apple, Arabidopsis, Chenopodium murale, membrane potential, salicylic acid
Abstract: Compounds exuded from roots play a key role in regulating plant allelopathic interactions. However, phytochormone profiling of root exudates and their contribution to an overall allelochemical activity of specific plant species is neglected topic in allelochemical research. Hairy root growth media of two different species, the fruit tree species Malus × domestica Borkh. and the herbaceous weed species Chenopodium murale L. were collected and analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). We found that most of the phytohormones exuded by the hairy roots of C. murale and M. domestica were associated with the acidic fraction (96.8% and 98.9%, respectively), including 2-oxindole-3-acetic acid, phenylacetic acid, salicylic acid (SA), benzoic acid (BzA), and abscisic acid, with SA and BzA being the most abundant, while those associated with the basic fraction, including cytokinins and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid, accounted for only 1% of the plant growth substances detected in both species. Exogenous application of 0.2 μM SA, which was released from the hairy roots of C. murale and accumulated in the culture media for four weeks, significantly impaired hairy root growth of M. domestica and also shoot and root growth of Arabidopsis seedlings. The disruptive effect of 0.2 μM SA on the membrane potential of M. domestica hairy root and Arabidopsis root cells was determined. The data obtained could be useful for planning further studies aimed at clarifying the contribution and role of exuded phytohormones to the overall allelopathic potential of these two plant species.
DOI: 10.1007/s00344-024-11328-5
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IEB authors: Petre I. Dobrev, Václav Motyka