Regulation of Microtubule Stability by Tubulin Phosphorylation in Arabidopsis thaliana Under Altered Gravity Conditions
Author ORCID
Abstract
Microtubules play a critical role in plant growth, development, and responses to environmental stimuli, including gravity. The BRIC-20 experiment, which analyzed proteomic and transcriptomic changes in Arabidopsis seedlings grown on the International Space Station (ISS), identified differential phosphorylation of 16 peptides in microgravity, including tubulin-α 1, 3, 4, and 6, which were preferentially phosphorylated at T349 on Earth. Phosphorylation at this site is associated with microtubule depolymerization, suggesting that reduced phosphorylation in microgravity may contribute to increased microtubule stability. Given the established role of microtubules in cellulose deposition, cytoskeletal organization, and gravity sensing, this study aims to investigate the regulatory function of tubulin phosphorylation in microgravity-induced microtubule dynamics. To elucidate this relationship, knockout mutants will be generated to assess the role of tubulin phosphorylation in root development, with phenotypic analyses focused on root curvature, gravitropic set point angle, and growth responses under clinostat-based altered gravity conditions. Additionally, phospho-mimic (T349E) and phospho-inhibitory (T349A) mutants will be constructed to determine whether constitutive phosphorylation or its inhibition influences microtubule organization, root growth directionality, and cellular stress responses. These mutants will be characterized through live-cell imaging of microtubule dynamics, reactive oxygen species (ROS) quantification, and cellulose deposition assays to evaluate how phosphorylation affects microtubule stability and structural integrity. Given that microtubule depolymerization is induced under hyperosmotic stress and ROS fluctuations, the potential role of ROS-mediated cytoskeletal adaptation under altered gravity conditions will also be explored. This study will provide insights into how tubulin phosphorylation modulates microtubule stability and plant adaptation to spaceflight conditions. Understanding these regulatory pathways may inform future strategies for optimizing plant growth and biomass production in microgravity, with implications for space agriculture and plant-based life support systems in long-term space missions.
Status
Graduate
Department
Environmental & Plant Biology
College
College of Arts and Sciences
Campus
Athens
Faculty Mentor
Dr. Sarah Wyatt
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Regulation of Microtubule Stability by Tubulin Phosphorylation in Arabidopsis thaliana Under Altered Gravity Conditions
Microtubules play a critical role in plant growth, development, and responses to environmental stimuli, including gravity. The BRIC-20 experiment, which analyzed proteomic and transcriptomic changes in Arabidopsis seedlings grown on the International Space Station (ISS), identified differential phosphorylation of 16 peptides in microgravity, including tubulin-α 1, 3, 4, and 6, which were preferentially phosphorylated at T349 on Earth. Phosphorylation at this site is associated with microtubule depolymerization, suggesting that reduced phosphorylation in microgravity may contribute to increased microtubule stability. Given the established role of microtubules in cellulose deposition, cytoskeletal organization, and gravity sensing, this study aims to investigate the regulatory function of tubulin phosphorylation in microgravity-induced microtubule dynamics. To elucidate this relationship, knockout mutants will be generated to assess the role of tubulin phosphorylation in root development, with phenotypic analyses focused on root curvature, gravitropic set point angle, and growth responses under clinostat-based altered gravity conditions. Additionally, phospho-mimic (T349E) and phospho-inhibitory (T349A) mutants will be constructed to determine whether constitutive phosphorylation or its inhibition influences microtubule organization, root growth directionality, and cellular stress responses. These mutants will be characterized through live-cell imaging of microtubule dynamics, reactive oxygen species (ROS) quantification, and cellulose deposition assays to evaluate how phosphorylation affects microtubule stability and structural integrity. Given that microtubule depolymerization is induced under hyperosmotic stress and ROS fluctuations, the potential role of ROS-mediated cytoskeletal adaptation under altered gravity conditions will also be explored. This study will provide insights into how tubulin phosphorylation modulates microtubule stability and plant adaptation to spaceflight conditions. Understanding these regulatory pathways may inform future strategies for optimizing plant growth and biomass production in microgravity, with implications for space agriculture and plant-based life support systems in long-term space missions.