Biology subjects

Ache, P.

Publications and source records attributed to Ache, P..

4 recordsLinked to original sources

bioRxiv2025

Under salt stress quinoa stomatal guard cells control transpiration in an ABA-primed manner

O_LIStomatal guard cells, located at the interface between the leaf and the atmosphere, play a key role in transpiration control and photosynthetic CO2 uptake. Halophytes like Chenopodium quinoa tolerate high soil salinity, but the mechanisms governing guard cell responses to salinity stress in relation to the associated epidermal bladder cells (EBCs) remain unknown. C_LIO_LIIn this study, responses of C. quinoa guard cells under salinity stress and external ABA application were analyzed using RNA profiling and voltage-clamp-based electrophysiology. C_LIO_LIUnder salt stress, guard cell RNA profiles reported the activation of ABA synthesis and signaling pathways. However, unlike EBCs, guard cells became transcriptionally insensitive to ABA. Voltage-clamp recordings revealed that under high Na+ concentrations, guard cells activity of K+ uptake channels remained unaffected, while they were impaired in ABA-induced activation of anion channels. As a consequence of a unique guard cell ABA response in salt-adapted plants, stomatal transpiration was reduced and CO2 sensitivity enhanced. C_LIO_LIWe propose that under salt stress, C. quinoa guard cells rewire their hormone signaling to switch from an ABA-sensitive to an ABA-insensitive mode. This adaptation may reflect the halophytes ability to perceive salinity as a non-stressful condition, allowing efficient water usage and sustained growth in saline environments. C_LI

plant biology↗

bioRxiv2024

Date palm acclimates to aridity by diverting organic osmolytes for root osmotic adjustment in parallel with leaf membrane remodeling and ROS scavenging

Highlight statementOsmotic strength of date palm roots increases with soil desiccation, for which the accumulation of organic osmolytes, such as sugars, is essential in complement to energetically cheap mineral osmotics. Date palm (Phoenix dactylifera L.) is an important crop in arid regions that is well-adapted to desert ecosystems. To understand the remarkable ability to grow and yield in water-limited environments, experiments were conducted in a simulated desert environment with water-withholding for up to four weeks. In response to drought, root, rather than leaf, osmotic strength increased, with sugars contributing more to the osmolyte increase than minerals. Consistently, carbon and amino acid metabolism was acclimated toward biosynthesis at both the transcriptional and translational levels. In leaves, a remodeling of membrane systems was observed, suggesting changes in thylakoid lipid composition, which together with the restructuring of the photosynthetic apparatus, indicated an acclimation preventing oxidative damage. Thus, xerophilic date palm avoids oxidative damage under drought by combined prevention and rapid detoxification of oxygen radicals. Although minerals were expected to serve as cheap key osmotics, date palm also relies on organic osmolytes for osmotic adjustment of the roots during desiccation. The diversion of these resources away from growth is consistent with date palms strategy of generally slow growth in harsh environments and clearly indicates a trade-off between growth and stress-related physiological responses.

plant biology↗

bioRxiv2021

Gaining or cutting SLAC: the evolution of plant guard cell signalling pathways

The evolution of adjustable plant pores (stomata), enabling CO2 acquisition in cuticle wax-sealed tissues was one of the most significant events in the development of life on land. But how did the guard cell signalling pathways that regulate stomatal movements evolve? We investigate this through comparison of fern and angiosperm guard cell transcriptomes. We find that these divergent plant groups share expression of similar genes in guard cells including biosynthesis and signalling genes for the drought stress hormone abscisic acid (ABA). However, despite conserved expression in guard cells, S-type anion channels from the SLAC/SLAH family - known for ABA-mediated stomatal closure in angiosperms - are not activated by the same pathways in ferns, highlighting likely differences in functionality. Examination of other land plant channels revealed a complex evolutionary history, featuring multiple gains or losses of SLAC activation mechanisms, as these channels were recruited to a role in stomatal closure. Taken together, the guard cells of flowering and non-flowering plants share similar core features, but also show lineage-specific and ecological niche-related adaptations, likely underlying differences in behaviour.

plant biology↗

bioRxiv2020

PYL8 ABA receptors of Phoenix dactylifera play a crucial role in response to abiotic stress and are stabilized by ABA

The identification of those prevailing ABA receptors and molecular mechanisms that trigger drought adaptation in crops well adapted to harsh conditions such as date palm (Phoenix dactylifera, Pd) sheds light on plant-environment interactions. We reveal that PdPYL8-like receptors are predominantly expressed under abiotic stress, being Pd27 the most expressed receptor in date palm. Therefore, subfamily I PdPYL8-like receptors have been selected for ABA signaling during abiotic stress response in this crop. Biochemical characterization of PdPYL8-like and PdPYL1-like receptors revealed receptor- and ABA-dependent inhibition of PP2Cs, which triggers activation of the pRD29B-LUC reporter in response to ABA. PdPYLs efficiently abolish PP2C-mediated repression of ABA signaling, but loss of the Trp lock in the seed-specific AHG1-like phosphatase PdPP2C79 markedly impairs its inhibition by ABA receptors. Characterization of Arabidopsis transgenic plants that express PdPYLs shows enhanced ABA signaling in seed, root and guard cells. Specifically, Pd27 overexpressing (OE) plants showed lower ABA content and were more efficient than wild type to lower transpiration at negative soil water potential, leading to enhanced drought tolerance. Finally, PdPYL8-like receptors accumulate after ABA treatment, which suggests that ABA-induced stabilization of these receptors operates in date palm for efficient boosting of ABA signaling in response to abiotic stress. HighlightDate palm response to abiotic stress is triggered through PYL8-like ABA receptors that are stabilized by the hormone, which boosts plant adaptation to drought mediated by ABA.

plant biology↗