Phosphatidic Acid Regulates Microtubule Organization by Interacting with MAP65-1 in Response to Salt Stress in Arabidopsis

Abstract

Membrane lipids play fundamental structural and regulatory roles in cell metabolism and signaling. Here, we report that phosphatidic acid (PA), a product of phospholipase D (PLD), regulates MAP65-1, a microtubule-associated protein, in response to salt stress. Knockout of the PLDa1 gene resulted in greater NaCl-induced disorganization of microtubules, which could not be recovered during or after removal of the stress. Salt affected the association of MAP65-1 with microtubules, leading to microtubule disorganization in plda1cells, which was alleviated by exogenous PA. PA bound to MAP65-1, increasing its activity in enhancing microtubule polymerization and bundling. Overexpression of MAP65-1 improved salt tolerance of Arabidopsis thaliana cells. Mutations of eight amino acids in MAP65-1 led to the loss of its binding to PA, microtubule-bundling activity, and promotion of salt tolerance. The plda1 map65-1 double mutant showed greater sensitivity to salt stress than did either single mutant. These results suggest that PLDa1-derived PA binds to MAP65-1, thus mediating microtubule stabilization and salt tolerance. The identification of MAP65-1 as a target of PA reveals a functional connection between membrane lipids and the cytoskeleton in environmental stress signaling.

Effect of n-butanol and cold pretreatment on the cytoskeleton and the ultrastructure of maize microspores when cultured in vitro

“…As recently discovered, phosphatidic acid has a regulating role in the case of microtubules as well. The binding of exogenously added PA to a microtubule associated protein MAP65-1, elevates the microtubule polymerization and bundling activity of this regulatory protein, stabilizing microtubule cytoskeleton during salt stress in Arabidopsis (Zhang et al 2012). Nevertheless, microtubule content did not elevated further, when various PA species were added to control cells, suggesting that MAP65-1 may have a stress-related role.…”

Phospholipids

“…13 Although Dhonukshe et al (2003) studied there was link between phospholipids and MTs, the underlying mechanisms that activation of PLD in BY-2 cells induces rapid MTs reorganization remain unclear. 4 Afterwards, Zhang et al (2012) first elucidated that PA interacted with microtubule cytoskeleton to regulate plants salt response in detail. More exactly, salt treatment activated PLDα1 followed by a rapid rise of PA. PA then bound to MAP65-1 (Microtubuleassociated protein 65-1) through specific amino acids and enhanced its activity of polymerizing and bundling cortical MTs.…”

“…9,10,[19][20][21][22] Phospholipase D (PLD), which can hydrolyze phospholipids into phosphatidic acid and head group, is involved in plant salt tolerance. Arabidopsis PLDα1 and PLDδ are proved to function cooperatively in high salinity.…”

“…[13][14][15] It has been well documented MTs and MFs take part in salt stress, heat shock, dehydration and drought. 10,12,13,[15][16][17][18] However, the exact mechanisms about how MTs and MFs sense cues and reorganize themselves in these processes remain to be elucidated.…”

“…In recent years, increasing studies uncover phospholipids are vital mediators in plant processes, e.g., stomatal movement, root hair development, nutrient uptake, cytoskeletal dynamics, salt stress and heat shock. [1][2][3][4][5][6][7][8][9][10][11][12] In plant kingdom, the cytoskeletal system consists of microtubules (MTs) and microfilaments (MFs). MTs are composed of α-and β-tubulins, which form dimers and then polymerize into MTs.…”