Plasma Membrane Fluidity: An Environment Thermal Detector in Plants

Abstract

The lipid matrix in cell membranes is a dynamic, bidimensional array of amphipathic molecules exhibiting mesomorphism, which contributes to the membrane fluidity changes in response to temperature fluctuation. As sessile organisms, plants must rapidly and accurately respond to environmental thermal variations. However, mechanisms underlying temperature perception in plants are poorly understood. We studied the thermal plasticity of membrane fluidity using three fluorescent probes across a temperature range of −5 to 41 °C in isolated microsomal fraction (MF), vacuolar membrane (VM), and plasma membrane (PM) vesicles from Arabidopsis plants. Results showed that PM were highly fluid and exhibited more phase transitions and hysteresis, while VM and MF lacked such attributes. These findings suggest that PM is an important cell hub with the capacity to rapidly undergo fluidity modifications in response to small changes of temperatures in ranges spanning those experienced in natural habitats. PM fluidity behaves as an ideal temperature detector: it is always present, covers the whole cell, responds quickly and with sensitivity to temperature variations, functions with a cell free-energy cost, and it is physically connected with potential thermal signal transducers to elicit a cell response. It is an optimal alternative for temperature detection selected for the plant kingdom.

Low-temperature and circadian signals are integrated by the sigma factor SIG5

“…7b), so regulation by HY5 and/or HYH also maintains PSII photosynthetic efficiency at low temperatures. During cold acclimation, sensing of low non-freezing temperatures leads to changes in membrane fluidity, cell wall structure and the accumulation of compatible solutes and antioxidants to increase freezing tolerance 1,5,56 . Previous studies have shown that greater damage to the photosynthetic apparatus of plants with lower freezing tolerance can manifest as reduced F v /F m during freezing 57 , as we identified for sig5-3 (Fig.…”

Quantification methods of determining brewer’s and pharmaceutical yeast cell viability: accuracy and impact of nanoparticles

“…However, a disadvantage of this approach is that it involves a sum term, which is affected by the manual error and cell number inhomogeneity. Also, many factors affect membrane fluidity, such as ethanol concentration [13,18] and heat stress [56]. Therefore, a new calibration curve needs to be performed for each condition.…”

Thermoprotection by a cell membrane-localized metacaspase in a green alga

“…In contrast to animals (Shuba, 2021), heat response in plants remains poorly characterized. It is postulated that both streptophytes and chlorophytes sense heat via an increase in the PM fluidity causing activation of the cyclic nucleotide-gated ion channels and controlled entry of the extracellular Ca 2+ to the cytosol, which further leads to the heat shock factor (HSF)-mediated transcriptional response and biosynthesis of necessary proteins, such as heat shock proteins (HSPs) (Mittler et al, 2012;Cano-Ramirez et al, 2021;Guihur et al, 2022). We initially thought that the compromised thermotolerance of crmca-ii strains was associated with aberrant HS sensing at the level of HSF and HSP production, but did not observe any differences in the transcript levels of HSFs and major HSPs known to execute HS response in Chlamydomonas (Zhang et al, 2022) between UVM4 and crmca-ii (data not shown).…”