Biology subjects

Caceres, P. D.

Publications and source records attributed to Caceres, P. D..

3 recordsLinked to original sources

bioRxiv2025

Root Hydraulic Conductivity and Transpiration in Arabidopsis: Coordination Revealed by a High-Stomatal-Density Mutant

Background and aimsUnderstanding the coordination between root and shoot hydraulics is fundamental for improving plant performance under water stress. In this study, we investigated how shoot traits that enhance transpiration influence root hydraulic properties, using the Arabidopsis thaliana double mutant epf1 epf2, characterized by high stomatal density and increased transpiration. MethodsPlant lines epf1 epf2 and Col-0 (wild type) were grown hydroponically and compared for stomatal traits, rate of water loss, leaf and root water relations, aquaporin expression, and root hydraulic conductivity (Lpr). Then, to assess responses to water deficit, osmotic stress was induced by adding 2% polyethylene glycol (PEG) to the nutrient solution seven days before measurements. Key resultsThe epf1 epf2 double mutant exhibited [~]150% higher stomatal density, yet stomatal conductance and short-term rosette water loss increased by only [~]30% relative to wild type. Despite higher water loss, the mutant maintained its leaf relative water content, concomitant with a more negative leaf osmotic potential; root osmotic potential was similar between genotypes. epf1 epf2 showed lower Lpr than Col-0. Aquaporin transcript levels and the relative aquaporin contribution to root water transport did not differ between genotypes. Under osmotic stress, Col-0 instead showed lower Lpr than epf1 epf2, again without changes in aquaporin expression or relative contribution. ConclusionsOur results highlight an active contribution of the root as a modulator of the whole-plant hydraulic balance. Across scenarios where xylem tension was expected to increase, stomatal aperture and Lpr decreased. We suggest that enhanced transpiration elevates xylem tension, which acts as a long-distance cue, eliciting coordinated reductions in stomatal aperture and Lpr, thereby constraining water flux.

plant biology↗

bioRxiv2025

A viral infection reshapes Arabidopsis water management via root hydraulics, aquaporin downregulation and osmotic adjustment

The effect of plant viruses on root water relations and on how roots and shoots coordinate under infection remains poorly understood. Using a hydroponic Arabidopsis thaliana-Turnip mosaic virus (TuMV) pathosystem, we integrated biometric, anatomical, hydraulic, and gas-exchange measurements to dissect how viral infection reshapes root-shoot water relations. TuMV impaired root development, as reflected by an early plateau of primary root elongation. At the functional level, infected plants exhibited a decrease in root hydraulic conductance per unit root mass, concomitant with transcriptional downregulation of root aquaporin genes. Despite this, the relative contribution of aquaporin-mediated water transport, assessed via sodium azide inhibition, remained unchanged, indicating that the virus downregulates total hydraulic capacity without altering the apoplastic-symplastic partitioning of water flow. Gas-exchange analysis revealed a virus-induced decoupling between stomatal conductance and net CO2 assimilation, resulting in a non-adaptive increase in intrinsic water-use efficiency. This loss of photosynthetic plasticity, combined with shoot-localized osmotic adjustment (more negative leaf osmotic potential and higher relative water content), points to a constrained, suboptimal physiological state. Multivariate analysis confirmed that variation in physiological traits largely drives phenotypic divergence between treatments. Together, these coordinated alterations, reduced root hydraulics, rigid gas-exchange relationships and passive hydraulic matching to a stunted shoot, depict plants locked into a low-performance equilibrium, poorly equipped to compete for water and carbon. This work reveals a systemic hydraulic-photosynthetic reconfiguration that could account for compromises in plant resilience and resource competitiveness. HighlightTuMV infection induces a coordinated whole-plant hydraulic reconfiguration characterized by premature growth arrest, reduced root hydraulic conductance, and decoupling of stomatal conductance from photosynthesis, resulting in a constrained physiological state.

plant biology↗

bioRxiv2025

Novel strategies to deal with salinity in Sorghum bicolor seedlings

Sorghum is a crop that has become more relevant in recent years due to its uses and properties (biofuel, gluten-free flours) as well as its versatility to grow in unfavorable environmental conditions. Salinity is one of the main abiotic stresses affecting crop production and yield worldwide. The aim of this work was to study the response of sorghum seedlings to soil salinity in two genotypes with known performance to cope with water stress. Physiological parameters related to plant water status as well as the sodium content in the plant were analyzed. We studied the possible role of pricklet and microhairs in the response to salt conditions. Our results showed a differential response to salinity, probably denoting different mechanisms that involve internal water redistribution (in 200 mM NaCl) and a specific replacement of silicon by sodium (when the NaCl reaches 300 mM). The main result was that sodium was absent in all analyzed hairs and leaf surface. Surprisingly, we detected the presence of silicon inside the pricklet at 300 mM NaCl after 24 hours, but not in the microhair. NIPs aquaporins could be involucrate in silicon transport. Our novel results provide further evidence regarding the role of silicon in the response to salt stress. HighlightGrain sorghum has a different strategy to deal with salinity stress depending on the salt concentration, that involves the leaves pricklets and the migration of silicon.

plant biology↗