Biology subjects

Ticha, T.

Publications and source records attributed to Ticha, T..

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↗

bioRxiv2025

Coping with stress: Transcriptional regulators linking cell wall integrity maintenance with primary-wall metabolism in Arabidopsis thaliana

Cell wall damage (CWD) and hyperosmotic stress elicit both distinct and overlapping transcriptional programs in plants. Responses to these stresses involve cell wall integrity (CWI) maintenance, which is mediated by receptor-like kinases such as THESEUS1 (THE1), yet the downstream regulators linking early signalling to primary cell-wall metabolism and stress-induced phytohormone biosynthesis remain poorly defined. We induced CWD and hyperosmotic stress in wild type and the1 mutant alleles with isoxaben (ISX) and sorbitol, and analysed the gene expression of treated seedlings by RNA-seq. From these data, we focused on 15 transcriptional regulators whose expression was responsive to treatments and showed dependency on THE1 activity. Following up, we performed various functional analyses in mutant lines of these candidates and identified transcription factors that influence primary cell-wall metabolism, growth, transcriptional control of cellulose production, resistance to CWD and hyperosmotic stress, as well as phytohormone and lignin biosynthesis. Our results identify JMJ17, bHLH, and CBP60A as essential transcriptional regulators involved in responses to CWD and hyperosmotic stress, and they provide a starting point for dissecting the transcriptional network that regulates CWI maintenance and primary cell wall metabolism. This study sheds light on a previously unknown signalling network that regulates primary cell wall synthesis in control and stress conditions, providing a basis for more resilient crop plant breeding in the future. Significance StatementPlants provide food and materials used by society, and their productivity depends on maintaining cell wall integrity (CWI) during growth, development, and environmental stress. The CWI maintenance mechanism, involving receptor-like kinases such as THESEUS1 (THE1), has been extensively investigated, yet the transcriptional regulators involved in primary wall metabolism and stress-induced phytohormone production remain unknown. Here, we integrate transcriptomics with functional genetic and physiological assays to identify transcription factors acting in a THE1-dependent/independent manner. These regulators link CWI, hyperosmotic stress, and cell wall damage to primary wall metabolism, lignification, phytohormone production, and root growth. Our findings reveal elements of the transcriptional network that coordinate CWI and primary cell wall formation with adaptive responses, generating insights to enhance crop stress resilience.

plant biology↗

bioRxiv2021

THESEUS1 modulates cell wall stiffness and abscisic acid production in Arabidopsis thaliana

Plant cells can be distinguished from animal cells by their cell walls and high turgor pressure. Although changes in turgor and stiffness of cell walls seem coordinated, we know little about the mechanism responsible for coordination. Evidence has accumulated that plants, like yeast, have a dedicated cell wall integrity maintenance mechanism. This mechanism monitors the functional integrity of the wall and maintains it through adaptive responses when cell wall damage occurs during growth, development, and interactions with the environment. The adaptive responses include osmo-sensitive-induction of phytohormone production, defence responses as well as changes in cell wall composition and structure. Here, we investigate how the cell wall integrity maintenance mechanism coordinates changes in cell wall stiffness and turgor in Arabidopsis thaliana. We show that the production of abscisic acid (ABA), the phytohormone modulating turgor pressure and responses to drought, depends on the presence of a functional cell wall. We find that the cell wall integrity sensor THESEUS1 modulates mechanical properties of walls, turgor loss point and ABA biosynthesis. We identify RECEPTOR-LIKE PROTEIN 12 as a new component of cell wall integrity maintenance controlling cell wall damage-induced jasmonic acid production. Based on the results we propose that THE1 is responsible for coordinating changes in turgor pressure and cell wall stiffness. Significance statementPlants need to constantly adapt to a changing environment. This includes responses to biotic and abiotic stress. Key elements influencing the response to abiotic stress are the plant cell walls surrounding all cells and the phytohormone abscisic acid, which influences turgor pressure in plants. Turgor pressure in plant cells is much higher than in animal cells and a key driver of plant growth and development. Here we investigate the mechanism regulating cell wall stiffness and coordinating changes in stiffness and turgor. We characterize key elements of the mechanism and dissect its mode of action. This knowledge will enable us to pursue novel approaches to improve plant resistance to drought stress, which is crucial in a rapidly changing environment.

plant biology↗

bioRxiv2020

The interplay of HSP90s with YDA regulates main body axis formation during early embryogenesis in Arabidopsis

The YODA kinase (YDA) pathway is intimately associated with the control of Arabidopsis thaliana embryo development but little is known regarding its regulators. Using genetic analysis, HEAT SHOCK PROTEINS 90 (HSP90s) emerge as potent regulators of YDA in the process of embryo development and patterning. This study is focused on the characterization and quantification of early embryonal traits of single and double hsp90 and yda mutants. The mutant analysis was supported by expression analyses of cell-specific WUSCHEL-RELATED HOMEOBOX 2 (WOX2) and WOX8 genes during early embryonic development. Chromatin immunoprecipitation assays corroborated the involvement of YDA and HSP90s in the epigenetic control of chromatin remodeling during early embryogenesis. Genetic interactions among HSP90s and members of the YDA signaling pathway affected the development of both embryo proper and suspensor. Impaired function of HSP90s or YDA had an impact on the spatiotemporal expression of WOX8 and WOX2 suggesting their essential role in cell fate determination and interference with auxin distribution. Hence, the interplay between HSP90s and YDA signaling cascade mediates the epigenetic control regulating the transcriptional networks shaping early embryo development.

plant biology↗

bioRxiv2018

Environment and HSP90 modulate MAPK stomatal developmental pathway

Stomatal ontogenesis is a key element of plant adaptation aiming to control photosynthetic efficiency and water management under fluctuating environments 1,2,3. Development of stomata is guided by endogenous and environmental cues and is tightly coupled to overall plant growth 1,2,3. YODA signaling pathway is essential to stomatal lineage specification4,5,6 since it regulates the activities of transcription factors such as SPEECHLESS (SPCH)7,8,9,10. Heat-shock proteins 90 (HSP90s) are evolutionarily conserved molecular chaperones implicated in a broad range of signalling pathways being integrated in interaction networks with client proteins11,12,13,14. Herein, based on genetic, molecular, biochemical, and cell biological evidence we report that heat-stress conditions affect phosphorylation and deactivation of SPCH and modulate stomatal density. We show that genetic and physical interactions between HSP90s and YODA control stomatal patterning, distribution and morphology. We provide solid evidence that HSP90s play a major role in transducing the heat-stress response since they act upstream and downstream of YODA signalling, regulate the activity and nucleocytoplasmic distribution of MAPKs, and the activation of SPCH. Thus, HSPs control the stomatal development both under normal temperature and acute heat-stress conditions. Our results demonstrate that HSP90s couple stomatal formation and patterning to environmental cues providing an adaptive mechanism of heat-stress tolerance response and stomatal formation in Arabidopsis.

plant biology↗