Microtubule Dynamics Plays a Vital Role in Plant Adaptation and Tolerance to Salt Stress.

Hyun Jin Chun,Mi Suk Park,Ye Jin Cha,Su Hyeon Lee,Lack Hyeon Lim,Byung Jun Jin,Sun Tae Kim,Dong-Won Bae,Dongwon Baek,Hyun Min Cho,Min Chul Kim,Dae-Jin Yun

doi:10.3390/ijms22115957

Abstract

Although recent studies suggest that the plant cytoskeleton is associated with plant stress responses, such as salt, cold, and drought, the molecular mechanism underlying microtubule function in plant salt stress response remains unclear. We performed a comparative proteomic analysis between control suspension-cultured cells (A0) and salt-adapted cells (A120) established from Arabidopsis root callus to investigate plant adaptation mechanisms to long-term salt stress. We identified 50 differentially expressed proteins (45 up- and 5 down-regulated proteins) in A120 cells compared with A0 cells. Gene ontology enrichment and protein network analyses indicated that differentially expressed proteins in A120 cells were strongly associated with cell structure-associated clusters, including cytoskeleton and cell wall biogenesis. Gene expression analysis revealed that expressions of cytoskeleton-related genes, such as FBA8, TUB3, TUB4, TUB7, TUB9, and ACT7, and a cell wall biogenesis-related gene, CCoAOMT1, were induced in salt-adapted A120 cells. Moreover, the loss-of-function mutant of Arabidopsis TUB9 gene, tub9, showed a hypersensitive phenotype to salt stress. Consistent overexpression of Arabidopsis TUB9 gene in rice transgenic plants enhanced tolerance to salt stress. Our results suggest that microtubules play crucial roles in plant adaptation and tolerance to salt stress. The modulation of microtubule-related gene expression can be an effective strategy for developing salt-tolerant crops.

Highlights

IntroductionPlant cells have adapted to salt stress by changing cell wall composition [2,3]
NaCl), we observed that the A120 cells showed distinct morphological changes compared with A0 cells, including spherical or ellipsoidal and isodiametric shapes (Figure 1a) with A0 cells, including spherical or ellipsoidal and isodiametric shapes (Figure 1a)
This study suggests that the morphological changes of plant cells are an essential cellular process for adaptation to prolonged salt stress

Summary

Introduction

Plant cells have adapted to salt stress by changing cell wall composition [2,3]. The RhEXP4, expansin A4 of rose, overexpressing Arabidopsis plants show increased seed germination, root growth, and several lateral roots under salt stress conditions [4]. A higher pectin content in root tips enhances plant tolerance to salt stress by increasing root growth compared with the cell wall composition in two soybean cultivars [5]. The Arabidopsis CC1 and CC2 proteins, along with cellulose synthases, interact with microtubules (MTs) and are essential for seedling growth under salt stress conditions [7]. The molecular mechanisms of changing cell wall dynamics by salt stress, including signal transduction and cell wall integrity pathways, remain unclear

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Conclusion