Biology subjects

Montesinos, J. C.

Publications and source records attributed to Montesinos, J. C..

5 recordsLinked to original sources

bioRxiv2026

The Receptor Kinase MEE39/ATHE Mediates Cell Wall Integrity Surveillance During Root Vascular Pathogen Infection

Plant cell wall (CW) integrity signaling enables early detection of microbial invasion, yet the receptors involved and their spatial and temporal dynamics during infection remain largely unknown. We identify ATHENA (ATHE)/MEE39, a previously uncharacterized malectin-like leucin-rich repeat receptor kinase (Mal-LRR-RK) that contributes to defense against the root vascular pathogen Fusarium oxysporum (Fo), particularly in outer root layers where colonization begins. ATHE abundance, localization, and endocytic trafficking are rapidly remodeled during infection, and loss of ATHE compromises basal immunity and early pathogen-induced transcriptional reprogramming. ATHE responds to altered cellulose synthesis, cellulose-derived oligosaccharides, mechanically induced CW perturbations, and the fungal secreted peptide Fo-RALF. In most of these contexts, ATHE acts together with the LRR-RK MIK2, forming a pathogen-strengthened RK complex that fine-tunes root responses to Fo. This represents the first example of a receptor complex visualized subcellularly in vivo during a plant-microbe interaction. Although Brassicaceae-specific, heterologous expression of ATHE enhanced tomato resistance to Fo, highlighting its functional relevance across plant lineages and its potential use for crop engineering. Our work reveals a previously unrecognized strategy by which plants decode microbial threats through dynamic CW-integrity surveillance.

plant biology↗

bioRxiv2023

Mechanical forces in extendable tissue matrix orient cell divisions via microtubule stabilization in Arabidopsis

Plant morphogenesis relies exclusively on oriented cell expansion and division. Nonetheless, the mechanism(s) determining division plane orientation remain elusive. Here we studied tissue healing after laser-assisted wounding in roots and uncovered how mechanical forces of cell expansion stabilize and reorient microtubule cytoskeleton for orientation of cell division. We revealed that root tissue functions as interconnected cell matrix with a radial gradient of tissue extendibility causing a predictable tissue deformation after wounding. This causes instant redirection of expansion in the surrounding cells and reorientation of microtubule arrays ultimately predicting cell division orientation. Microtubules are destabilized under low tension, whereas stretching of cells, either through wounding or external aspiration immediately induce their polymerisation. The higher microtubule abundance in the stretched cell parts leads to reorientation microtubule arrays and ultimately cell division planes. This provides a long-sought mechanism for flexible re-arrangement of cell divisions by mechanical forces for tissue reconstruction and plant architecture.

cell biology↗

bioRxiv2021

Impairment of the cellulose degradation machinery enhances fungal virulence but limits reproductive fitness

Fungal endophytes grow in the apoplastic space, in constant contact with the plant cell wall (CW) that hinders microbe progression, while representing a source of nutrients. Although numerous fungal CW modifying proteins have been identified, their role during host colonization remains underexplored. Here we show that the root-infecting plant pathogen Fusarium oxysporum (Fo) does not require its complete arsenal of cellulases to infect the host plant. Quite the opposite, Fo mutants impaired in cellulose degradation become hypervirulent by enhancing the secretion of virulence factors. On the other hand, the reduction on cellulase activity had a severe negative effect on saprophytic growth and microconidia production during the final stages of the Fo infection cycle. These findings enhance our understanding on the function of plant CW degradation on the outcome of host-microbe interactions and reveal an unexpected role of cellulose degradation in a pathogens evolutionary success. TeaserUnexpectedly, fungi compromised in their capacity to degrade plant cellulose are hypervirulent but impaired in sporulation.

microbiology↗

bioRxiv2020

Modulation of root growth by nutrient-defined fine-tuning of polar auxin transport

Nitrogen is an essential macronutrient and its availability in soil plays a critical role in plant growth, development and impacts agricultural productivity. Plants have evolved different strategies to sense and respond to heterogeneous nitrogen distribution. Modulating root system architecture, including primary root growth and branching, is among the most essential plant adaptions to ensure adequate nitrogen acquisition. However, the immediate molecular pathways coordinating the adjustment of root growth in response to varying nitrogen sources are poorly understood. Here, using a combination of physiological, live in vivo high- and super resolution imaging, we describe a novel adaptation strategy of root growth on available nitrogen source. We show that growth, i.e. tissue-specific cell division and elongation rates are fine-tuned by modulating auxin flux within and between tissues. Changes in auxin redistribution are achieved by nitrogen source dependent post-translational modification of PIN2, a major auxin efflux carrier, at an uncharacterized, evolutionary conserved phosphosite. Further, we generate a computer model based on our results which successfully recapitulate our experimental observations and creates new predictions that could broaden our understanding of root growth mechanisms in the dynamic environment.

plant biology↗

bioRxiv2019

Cytokinin fluoroprobe and receptor CRE1/AHK4 localize to both plasma membrane and endoplasmic reticulum

The plant hormone cytokinin regulates various cell and developmental processes, including cell division and differentiation, embryogenesis, activity of shoot and root apical meristems, formation of shoot and root lateral organs and others 1. Cytokinins are perceived by a subfamily of sensor histidine kinases (HKs), which via a two-component phosphorelay cascade activate transcriptional responses in the nucleus. Based on the subcellular localization of cytokinin receptors in various transient expression systems, such as tobacco leaf epidermal cells, and membrane fractionation experiments of Arabidopsis and maize, the endoplasmic reticulum (ER) membrane has been proposed as a principal hormone perception site 2-4. Intriguingly, recent study of the cytokinin transporter PUP14 has pointed out that the plasma membrane (PM)-mediated signalling might play an important role in establishment of cytokinin response gradients in various plant organs 5. However, localization of cytokinin HK receptors to the PM, although initially suggested 6, remains ambiguous. Here, by monitoring subcellular localizations of the fluorescently labelled natural cytokinin probe iP-NBD 7 and the cytokinin receptor ARABIDOPSIS HISTIDINE KINASE 4 (CRE1/AHK4) fused to GFP reporter, we show that pools of the ER-located cytokinin fluoroprobes and receptors can enter the secretory pathway and reach the PM. We demonstrate that in cells of the root apical meristem, CRE1/AHK4 localizes to the PM and the cell plate of dividing meristematic cells. Brefeldin A (BFA) experiments revealed vesicular recycling of the receptor and its accumulation in BFA compartments. Our results provide a new perspective on cytokinin signalling and the possibility of multiple sites of perception at PM and ER, which may determine specific outputs of cytokinin signalling.

plant biology↗