Biology subjects

Alonso Baez, L.

Publications and source records attributed to Alonso Baez, L..

5 recordsLinked to original sources

bioRxiv2026

The interactome of the receptor kinase THESEUS1 reveals how cell wall integrity is linked to hormone signalling in Arabidopsis

The receptor kinase THESEUS1 (THE1) activates responses to impairment of cell wall integrity (CWI). However, the interaction partners enabling THE1 to mediate the responses remain underexplored, impeding a mechanistic understanding of THE1. We produced a set of THE1 GFP fusion constructs in which THE1 is either wild type, mutated in its kinase domain, has a loss of function mutation in its ectodomain, or lacks the kinase or extracellular domain. We used these constructs to perform localization studies and immunoprecipitation liquid chromatography tandem mass spectrometry under control and stress conditions (isoxaben induced cell wall damage and sorbitol induced hyperosmotic stress) to identify the THE1 interactome. The interactome of THE1 changed in a context dependent manner, linking THE1 to known signaling components in CWI maintenance and phytohormone response (such as proton pumps, calcium pumps, other receptor kinases or cellulose synthesis regulators). Moreover, we identified novel interactors, associating THE1 with hitherto unexplored signaling pathways in response to CWI impairment. Our results also suggest that the THE1G37D protein (corresponding to the the1 1 allele) is retained in the endoplasmic reticulum, explaining its loss of function phenotype. The THE1 interactome and localization data provide the foundation to build a mechanistic understanding of THE1 mediated CWI maintenance.

plant biology↗

bioRxiv2026

P2K1 P2K2 Coordinate Early, Structure-Specific Mechanical Adaptations to Osmotic and Cell Wall Stress in Arabidopsis Roots

The cell wall and plasma membrane (PM) form the interface between a plant cell and its environment yet how their mechanical properties change in response to stress is poorly understood. Here we investigate how the mechanical properties of the cell wall, plasma membrane, and vacuole change in vivo in Arabidopsis thaliana roots in response to hyperosmotic stress and cell wall damage (CWD) using a solvatochromic dye, molecular rotors, and Brillouin microscopy. We observe initially dynamic changes in mechanical properties of the PM that are sensitive to both hyperosmotic stress and CWD, while the cell wall changes are limited and the vacuole adapts only after several hours. In the p2k1 p2k2 double mutant, lacking receptors for extracellular ATP perception, sorbitol-induced effects on PM mechanostasis and early isoxaben-induced increases in PM order are lost. Our results indicate that P2K1 and P2K2 are required to modulate adaptive changes in mechanical properties of the PM induced by hyperosmotic stress and CWD.

plant biology↗

bioRxiv2026

Mechanisms underlying the defective development of xyloglucan-deficient root hairs in Arabidopsis thaliana

Hemicellulosic xyloglucan is abundant in the primary cell walls of eudicots and non-gramineous monocots and contributes to their mechanical integrity. Its deficiency results in morphologically abnormal root hairs in Arabidopsis mutants lacking either two XYLOGLUCAN XYLOSYLTRANSFERASE (xxt1 xxt2) or five CELLULOSE SYNTHASE-LIKE C (cslc-{triangleup}5) genes, but the cellular and biomechanical mechanisms underlying these abnormalities have remained unexplored. We combined multiple imaging modalities and quantitative modeling to unmask these mechanisms, first observing that xyloglucan-deficient mutants produced fewer and shorter root hairs that grew slower than wild type. Xyloglucan-deficient trichoblasts showed root hair initiation defects, helping to explain the sparseness of root hairs in these mutants. The mutant root hairs also had lower turgor pressure, thicker walls, and wider cross-sections, that explain lack of anisotropic growth, but cellulose organization appeared normal in xyloglucan-deficient root hairs. Brillouin microscopy suggested that xyloglucan-deficient root hairs were softer than wild-type root hairs. Finite element modeling of mutant root hairs predicted lower surface stress and growth rates, which were directly proportional to turgor pressure and inversely proportional to wall thickness. Stress patterns on models hint at potential mechanisms of bulging in xyloglucan-deficient root hairs. We propose that though cellulose orientation specifies the axis of cell expansion, it cannot enforce it without xyloglucan that interlinks microfibrils into a load-bearing network, identifying matrix-cellulose interaction as a distinct and necessary determinant of anisotropic plant cell growth.

cell biology↗

bioRxiv2025

Transgenerational polarity axis inheritance during Ceratopteris embryogenesis

For sexually reproducing organisms to pass on their genetic information, progeny must successfully establish. Various life history strategies have evolved, using either dispersal of large numbers of progeny or intensive nurturing of a few. Most plants use the former strategy, but ferns generate a single embryo in the exact same location as the mother, and it is unknown how progeny success is promoted, or how embryogenesis is adapted. By studying Ceratopteris richardii embryogenesis, we find that maternal tissues guide orientation of the early embryo body axis, thus aligning its root pole towards the homologous maternal rhizoids. We find that axis polarity inheritance is mediated by maternal tissue mechanical patterns, and thus identify a robust mechanism for progeny establishment as a nurturing strategy in plants.

plant biology↗

bioRxiv2025

The mechanical properties of Arabidopsis thaliana roots adapt dynamically during development and to stress

Mechanical properties of plant cells and tissues change dynamically, influencing plant growth, development, and interactions with the environment. Despite their central roles in plant life, current knowledge of how these properties change in vivo is very limited. Here we have combined Brillouin microscopy and molecular rotors to investigate stiffness, viscosity and porosity in living Arabidopsis thaliana seedling roots during differentiation and in response to stress and genetic manipulation. We found that mechanical properties change in a cell- and tissue-specific manner. The properties change dynamically during differentiation to support directional cell expansion. Cell-type-specific adaptations are induced within hours in response to stress or changes in cell wall metabolism. The findings form the foundation for future studies to characterize regulatory mechanisms linking biochemical signaling and mechanical properties.

plant biology↗