Concentration of Benzoxazinoids in Roots of Field-Grown Wheat (Triticum aestivum L.) Varieties

Abstract

Benzoxazinones are naturally occurring secondary metabolites of some Gramineae plants, responsible for their resistance to some pathogenic fungi and for their allelopathic action. Six varieties of winter wheat grown in fields under organic or conventional systems and 11 old accessions were tested for two consecutive seasons and three plant development stages for the concentration in their roots of cyclic hydroxamic acids and their degradation products. This is the first report of six benzoxazinones analyzed in plants grown in the field. An analytical technique employing LC-DAD was used for determination. It was shown that 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, its degradation product 6-methoxybenzoxazolin-2-one, and the lactam 2-hydroxy-7-methoxy-1,4-benzoxazin-2-one were predominant compounds in all tested samples. Their concentrations significantly differed with plant development stage and season, but no significant differences were found between varieties and between plant cultivation systems. The concentrations of 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) and its degradation product benzoxazolin-2-one (BOA) were much lower, ranging from 60 to 430 mg/kg of dry matter, depending on accession, stage of development, and season. There was no significant difference found between plants grown in different cultivation systems, but there were significant differences between old and new varieties; concentrations of DIBOA and its derivatives were significantly lower in old accessions. It was concluded that the concentrations of DIBOA and BOA, which are precursors of highly fungicidal 2-aminophenol, 2-amino-3H-phenoxazin-3-one, and 2-acetylamino-3H-phenoxazin-3-one, are theoretically high enough to protect plants against some soilborne pathogens.

UPLC‐QTOF/MS metabolic profiling unveils urinary changes in humans after a whole grain rye versus refined wheat bread intervention

“…The identified benzoxazinoid compounds were excreted in urine, with HBOA‐glc as a major metabolite. In our study we were able to identify the sulphated form of 2‐aminophenol, which is present in wheat and rye grains in concentrations high enough to protect them against some soil‐borne pathogens and also annotate one of its precursors, DIBOA, as a sulphated conjugate. Both metabolites were excreted to a higher extent after the whole grain RB than refined WB diet.…”

Degradation of the benzoxazolinone class of phytoalexins is important for virulence of Fusarium pseudograminearum towards wheat

“…Correlations between higher benzoxazinoid concentrations and both FHB resistance (Soltoft et al ., ) and yield in wheat (Silva et al ., ) have been reported using a small number of cultivars. Wheat cultivars show significant differences in the total amount and proportions of benzoxazinoids found in their roots (Stochmal et al ., ; Villagrasa et al ., ), leaves and grain (Villagrasa et al ., ), although again only a small number of cultivars have been analysed. Although the correlation between benzoxazalinone levels and disease resistance has not been examined for Fusarium crown and root rot diseases, these defence compounds may also have an effect on these diseases if their concentrations are increased via traditional or molecular breeding approaches.…”

Interference of allelopathic wheat with different weeds

“…In particular, a holistic approach to research into allelopathy involved in benzoxazinoids from wheat was launched in the FATEALLCHEM project of the European Union . Among benzoxazinoids, 2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one (DIMBOA) is a dominant allelochemical . Through the release of allelochemical DIMBOA, allelopathic wheat can suppress weeds and provide a competitive advantage for its own growth .…”