Time point- and plant part-specific changes in phloem exudate metabolites of leaves and ears of wheat in response to drought and effects on aphids

PLoS One. 2022 Jan 25;17(1):e0262671. doi: 10.1371/journal.pone.0262671. eCollection 2022.

Abstract

Alterations in the frequency and intensity of drought events are expected due to climate change and might have consequences for plant metabolism and the development of plant antagonists. In this study, the responses of spring wheat (Triticum aestivum) and one of its major pests, the aphid Sitobion avenae, to different drought regimes were investigated, considering different time points and plant parts. Plants were kept well-watered or subjected to either continuous or pulsed drought. Phloem exudates were collected twice from leaves and once from ears during the growth period and concentrations of amino acids, organic acids and sugars were determined. Population growth and survival of the aphid S. avenae were monitored on these plant parts. Relative concentrations of metabolites in the phloem exudates varied with the time point, the plant part as well as the irrigation regime. Pronounced increases in relative concentrations were found for proline, especially in pulsed drought-stressed plants. Moreover, relative concentrations of sucrose were lower in phloem exudates of ears than in those of leaves. The population growth and survival of aphids were decreased on plants subjected to drought and populations grew twice as large on ears compared to leaves. Our study revealed that changes in irrigation frequency and intensity modulate plant-aphid interactions. These effects may at least partly be mediated by changes in the metabolic composition of the phloem sap.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Aphids*
  • Carbohydrates / analysis
  • Dehydration
  • Herbivory
  • Phloem / metabolism*
  • Phloem / parasitology
  • Plant Exudates / chemistry
  • Plant Exudates / metabolism*
  • Plant Leaves / metabolism*
  • Plant Leaves / parasitology
  • Time Factors
  • Triticum* / metabolism
  • Triticum* / parasitology

Substances

  • Amino Acids
  • Carbohydrates
  • Plant Exudates

Grants and funding

This work was funded by a grant of the Deutsche Forschungsgemeinschaft (MU 1829/23-1).