Targeted metabolomics unveil alteration in accumulation and root exudation of flavonoids as a response to interspecific competition

Abstract

ABSTRACT This study aimed to elucidate the chemical response of hairy vetch (Vicia villosa Roth) to interspecific competition by rye (Secale cereale L.). Hairy vetch plants were grown as target plants in a mixture with different densities of rye plants (0, 1, 2, and 4). Twelve flavonoids in the shoot, root, and root exudate of hairy vetch plants were quantified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Kaempferol 3-O-{β-D-rhamnosyl-(1->6)-[β-D-xylosyl)-(1->2)]-β-D-galactoside} (Kaempferol-Rha-Xyl-Gal) was the predominant flavonoid found in shoots, roots, and root exudate of hairy vetch plant. Co-cultivation of hairy vetch with one rye plant increased the concentration of kaempferol-Rha-Xyl-Gal in hairy vetch root exudates. However, the concentration was reduced when co-cultivated with 2 or 4 rye plants. This study revealed that low levels of competition increased root exudation of kaempferol-Rha-Xyl-Gal, while higher levels of competition negatively affected production and root exudation of kaempferol-Rha-Xyl-Gal by hairy vetch.