Drought stress stimulates endocytosis and modifies membrane lipid order of rhizodermal cells of Medicago truncatula in a genotype-dependent manner

Abstract

Background Drought stress negatively affects plant growth and productivity. Plants sense soil drought at the root level but the underlying mechanisms remain unclear. At the cell level, we aim to reveal the short-term root perception of drought stress through membrane dynamics. Results In our study, 15 Medicago truncatula accessions were exposed to a polyethylene glycol (PEG)-induced drought stress, leading to contrasted ecophysiological responses, in particular related to root architecture plasticity. In the reference accession Jemalong A17, identified as drought susceptible, we analyzed lateral roots by imaging of membrane-localized fluorescent probes using confocal microscopy. We found that PEG stimulated endocytosis especially in cells belonging to the growth differentiation zone (GDZ). The mapping of membrane lipid order in cells along the root apex showed that membranes of root cap cells were more ordered than those of more differentiated cells. Moreover, PEG triggered a significant increase in membrane lipid order of rhizodermal cells from the GDZ. We initiated the membrane analysis in the drought resistant accession HM298, which did not reveal such membrane modifications in response to PEG. Conclusions Our data demonstrated that the plasma membranes of root cells from a susceptible genotype perceived drought stress by modulating their physical state both via a stimulation of endocytosis and a modification of the degree of lipid order, which could be proposed as mechanisms required for signal transduction. Electronic supplementary material The online version of this article (10.1186/s12870-019-1814-y) contains supplementary material, which is available to authorized users.

Chemically Functionalized Water-Soluble Single-Walled Carbon Nanotubes Obstruct Vesicular/Plasmalemmal Recycling in Astrocytes Down-Stream of Calcium Ions

“…Namely, treatment of the drought-susceptible barrel clover (Medicago truncatula) accession Jemalong A17 for 5 days with 15% PEG (higher molecular weight of 8000) stimulated endocytosis in rhizodermal cells of the upper growth differentiation zone 4 of the roots. This effect, qualitatively opposite to what we observed in astrocytes using the same recycling dye FM4-64, was absent when the drought-resistant succession HM298 was used [ 57 ]. Undeniably, comparison between astrocytes isolated from the visual cortex of a rodent and rhizodermal cells in the roots of a legume may look awkward at the first sight.…”

“…Undeniably, comparison between astrocytes isolated from the visual cortex of a rodent and rhizodermal cells in the roots of a legume may look awkward at the first sight. However, in legumes the PEG can simulate water deficit [ 57 , 58 ]. Given the well-recognized astrocytic function in water balance [ 59 ], it is tempting to speculate that the effects of PEG on vesicular recycling we observed in astrocytes may be related to the activity of aquaporin-4, a water channel expressed on the plasma membrane of astrocytes in the mammalian cerebrum [ 60 ].…”

Arbuscular Mycorrhizal Fungi and K-Humate Combined as Biostimulants: Changes in Antioxidant Defense System and Radical Scavenging Capacity in Elaeagnus angustifolia

“…When plants encounter undesirable environmental conditions, cellular homeostasis and cell membrane structures change (Couchoud et al 2019;Gigon et al 2004;Miller et al 1971). As a result of this process, ROS such as H 2 O 2 , O 2 •− , 1 O 2 , and OH .…”

Membrane dynamics during individual and combined abiotic stresses in plants and tools to study the same

“…Moderate water stress causes modifications in the physical properties of membrane lipids that can be sensed by cells through the sensory membrane proteins, such as mechanosensitive ion channels and receptor kinases. Intense drought stress disrupts the PM, leading to the loss of membrane integrity and makes the membrane more rigid (Couchoud et al 2019). Furthermore, dehydration induces ROS production, which, in turn, causes oxidative damage to membrane lipids and decreases membrane fluidity (Fig.…”