Ethylene Signaling Modulates Cortical Microtubule Reassembly in Response to Salt Stress.

Regulation of cortical microtubule reorganization is essential for plant cell survival under high salinity conditions. In response to salt stress, microtubules undergo rapid depolymerization followed by reassembly to form a new microtubule network that promotes cell survival; however, the upstream regulatory mechanisms for this recovery response are largely unknown. In this study, we demonstrate that ethylene signaling facilitates salt stress-induced reassembly of cortical microtubules in Arabidopsis (Arabidopsis thaliana). Microtubule depolymerization was not affected under salt stress following the suppression of ethylene signaling with Ag+ or in ethylene-insensitive mutants, whereas microtubule reassembly was significantly inhibited. ETHYLENE-INSENSITIVE3, a key transcription factor in the ethylene signaling pathway, was shown to play a central role in microtubule reassembly under salt stress. In addition, we performed functional characterization of the microtubule-stabilizing protein WAVE-DAMPENED2-LIKE5 (WDL5), which was found to promote ethylene-associated microtubule reassembly and plant salt stress tolerance. These findings indicate that ethylene signaling regulates microtubule reassembly by up-regulating WDL5 expression in response to salt stress, thereby implicating ethylene signaling in salt-stress tolerance in plants.