Biology subjects

Kesten, C.

Publications and source records attributed to Kesten, C..

4 recordsLinked to original sources

bioRxiv2022

Vascular fungi alter the apoplastic purinergic signaling in plants by deregulating the homeostasis of extracellular ATP and its metabolite adenosine

Purinergic signaling activated by extracellular nucleotides and their derivative nucleosides trigger sophisticated signaling networks. The outcome of these pathways determine the capacity of the organism to survive under challenging conditions. Both extracellular ATP (eATP) and Adenosine (eAdo) act as secondary messengers in mammals, essential for immunosuppressive responses. Despite the clear role of eATP as a plant damage-associated molecular pattern, the function of its nucleoside, eAdo, and of the eAdo/eATP balance in plant stress response remain to be fully elucidated. This is particularly relevant in the context of plant/microbe interaction, where the intruder manipulates the extracellular matrix. Here, we identify Ado as a main elicitor secreted by the vascular fungus Fusarium oxysporum. We show that eAdo modulates the plants susceptibility to fungal colonization by altering eATP-mediated physiological immune responses, such as apoplastic pH and calcium homeostasis. Our work indicates that plant pathogens actively imbalance the eAdo/eATP levels as a virulence mechanism. One Sentence SummaryThe apoplastic Adenosine/ATP balance is a messenger for plant defense and can be manipulated by the fungal pathogen F. oxysporum.

plant biology↗

bioRxiv2022

Peripheral membrane proteins modulate stress tolerance by safeguarding cellulose synthases

Controlled primary cell wall remodeling adapts plant growth under stressful conditions, but how these changes are conveyed to adjust cellulose synthesis is unknown. Here, we identify the Tetratricopeptide Thioredoxin-Like (TTL) proteins as new members of the cellulose synthase complex (CSC) and describe their unique and hitherto unknown dynamic association with the CSC under cellulose-deficient conditions. We find that TTLs are essential for maintaining cellulose synthesis under salinity stress, establishing a stress-resilient cortical microtubule array, and stabilizing CSCs at the plasma membrane. To fulfill these functions, TTLs interact with Cellulose Synthase1 (CESA1) and engage with cortical microtubules to promote their polymerization. We propose that TTLs function as bridges connecting stress perception with dynamic regulation of cellulose biosynthesis at the plasma membrane. One Sentence SummaryTTLs are peripheral membrane proteins that maintain the integrity of the cellulose synthase complex upon adverse conditions.

plant biology↗

bioRxiv2019

Pathogen-induced pH changes regulate the growth-defense balance of plants

Environmental adaptation of organisms relies on fast perception and response to external signals, which lead to developmental changes. Plant cell growth is strongly dependent on cell wall remodeling. However, little is known about cell wall-related sensing of biotic stimuli and the downstream mechanisms that coordinate growth and defense responses. We generated genetically encoded pH sensors to determine absolute pH changes across the plasma membrane in response to biotic stress. A rapid apoplastic acidification by phosphorylation-based proton pump activation was followed by an acidification of the cortical side of the plasma membrane in response to the fungus Fusarium oxysporum. The proton chemical gradient modulation immediately reduced cellulose synthesis and cell growth and, furthermore, had a direct influence on the pathogenicity of the fungus. All these effects were dependent on the COMPANION OF CELLULOSE SYNTHASE proteins that are thus at the nexus of plant growth and defense. Hence, our discoveries show a remarkable connection between plant biomass production, immunity, and pH control, and advance our ability to investigate the plant growth-defense balance.

plant biology↗

bioRxiv2018

A molecular mechanism for salt stress-induced microtubule array formation in Arabidopsis

Microtubules are filamentous structures necessary for cell division, motility and morphology, with dynamics critically regulated by microtubule-associated proteins (MAPs). We outline the molecular mechanism by which the MAP, COMPANION OF CELLULOSE SYNTHASE1 (CC1), controls microtubule bundling and dynamics to sustain plant growth under salt stress. CC1 contains an intrinsically disordered N-terminus that links microtubules at evenly distributed distances through four conserved hydrophobic regions. NMR analyses revealed that two neighboring residues in the first hydrophobic binding motif are crucial for the microtubule interaction, which we confirmed through live cell analyses. The microtubule-binding mechanism of CC1 is remarkably similar to that of the prominent neuropathology-related protein Tau, indicating evolutionary convergence of MAP functions across animal and plant cells.

cell biology↗