Sasse Schlaepfer, J. | bioRxiv Science

bioRxiv2024

Distinct metabolite profiles in tissues and exudates of a monocot and dicot shaped by the environment

Plants exhibit remarkable plasticity in response to environmental changes. Understanding how plants adapt to diverse environmental conditions through changes in their metabolite profiles can provide insights into their adaptive strategies under suboptimal climate conditions. For this, metabolite profiles of tissues and root-derived, exuded compounds in various environmental conditions need to be characterized. Here, we compare the shoot, root, and root exudate metabolite profiles of the monocot Brachypodium distachyon and the dicot Arabidopsis thaliana grown in sterile, non-sterile, and sucrose-supplied basal salt medium or soil extract to represent natural and various standard laboratory conditions. We report unique metabolite fingerprints in shoots and roots for each species and environmental condition. Exuded compounds of Arabidopsis displayed higher sensitivity to soil extract conditions, whereas Brachypodium showed significant changes in response to non-sterile conditions. Organic acids, lipids, organic oxygen compounds, and phenylpropanoids were major contributors to the observed differences. Our results highlight the importance of considering environmental aspects when investigating plant metabolism and point towards crucial chemical classes involved in plant-microbe-environment interactions.

plant biology↗

bioRxiv2019

Root morphology and exudate availability is shaped by particle size and chemistry in Brachypodium distachyon

Root morphology and exudation define a plants sphere of influence in soils, and are in turn shaped by the physiochemical characteristics of soil. We explored how particle size and chemistry of growth substrates affect root morphology and exudation of the model grass Brachypodium distachyon. Root fresh weight and root lengths were correlated with particle size, whereas root number and shoot weight remained constant. Mass spectrometry imaging suggested that both, root length and number shape root exudation. Exudate metabolite profiles detected with liquid chromatography / mass spectrometry were comparable for plants growing in glass beads or sand with various particles sizes, but distinct for plants growing in clay. However, when exudates of clay-grown plants were collected by removing the plants from the substrate, their exudate profile was similar to sand- or glass beads-grown plants. Clay particles sorbed 20% of compounds exuded by clay-grown plants, and 70% of compounds of a defined exudate medium. The sorbed compounds belonged to a range of chemical classes, among them nucleosides/nucleotides, organic acids, sugars, and amino acids. Some of the sorbed compounds could be de-sorbed by a rhizobacterium (Pseudomonas fluorescens WCS415), supporting its growth. We show that root morphology is affected by substrate size, and that root exudation in contrast is not affected by substrate size or chemistry. The availability of exuded compounds, however, depends on the substrate present. These findings further support the critical importance of the physiochemical properties of soils are crucial to consider when investigating plant morphology, exudation, and plant-microbe interactions.

plant biology↗