Arabidopsis phospholipase D alpha 1-derived phosphatidic acid regulates microtubule organization and cell development under microtubule-interacting drugs treatment

Abstract

Phospholipase D (PLD) and its product phosphatidic acid (PA) are emerging as essential regulators of cytoskeleton organization in plants. However, the underlying molecular mechanisms of PA-mediated microtubule reorganization in plants remain largely unknown. In this study, we used pharmacological and genetic approaches to analyze the function of Arabidopsis thaliana PLDα1 in the regulation of microtubule organization and cell development in response to microtubule-affecting drugs. Treatment with the microtubule-stabilizing drug paclitaxel resulted in less growth inhibition and decreased rightward slant of roots, longitudinal alignment of microtubules, and enhanced length of hypocotyl epidermal cells in the pldα1 mutant, the phenotype of which was rescued by exogenous application of PA. Moreover, the pldα1 mutant was sensitive to the microtubule-disrupting drugs oryzalin and propyzamide in terms of seedling survival ratio, left-skewing angle of roots and microtubule organization. In addition, both disruption and stabilization of microtubules induced by drugs activated PLDα1 activity. Our findings demonstrate that in A. thaliana, PLDα1/PA might regulate cell development by modulating microtubule organization in an activity-dependent manner.

Gene Expression Pattern and Protein Localization of Arabidopsis Phospholipase D Alpha 1 Revealed by Advanced Light-Sheet and Super-Resolution Microscopy

“…Although PLDα1 is the most predominant PLD in plants, pldα1 knockout mutants do not exhibit significant phenotypical changes (Fan et al, 1997 ; Zhang et al, 2012 ). Nevertheless, PLDα1 controls proper water balance in plants responding to ABA by stomatal closure and this response is impaired in the pldα1 knockout mutants (Jiang et al, 2014 ; Pleskot et al, 2014 ; Zhang et al, 2017a ). To verify that pldα1-1 and pldα1-2 mutants were complemented with proPLDα1::PLDα1:YFP construct and show wild type-like behavior, we examined stomatal closure ability of these revertants by measuring stomatal aperture in cotyledons of 7 days old plants after treatment with 10 μM ABA.…”

“…Under normal conditions, knockout mutant pldα1 showed no changes in microtubule organization and density as compared to wild type plants (Zhang et al, 2012 ). However, PLDα1 knockout in Arabidopsis leads to more severe disruption of cortical microtubules by inhibitors (Zhang et al, 2017a ) or under salt stress conditions (Zhang et al, 2012 ). Furthermore, under the salt stress conditions PLDα1 is activated and produce PA which directs AtMAP65-1 to the plasma membrane, leading to microtubule stabilization and enhanced cell protection (Zhang et al, 2012 ; Pleskot et al, 2014 ).…”

“…Later studies on transgenic Arabidopsis cell lines using pull-down assay with GFP tagged PLDδ identified PLDδ as a cortical microtubule-binding protein (Andreeva et al, 2009 ; Ho et al, 2009 ; Hong et al, 2016 ). Such regulatory interactions among microtubules and PLD isoforms (particularly the Arabidopsis PLDα1 isoform) proved to have functional consequences during plant responses to salt and hyperosmotic stress (Zhang et al, 2012 ), ABA-induced stomatal closure (Jiang et al, 2014 ), and drug-induced microtubule reorganization (Zhang et al, 2017a ). One prominent target of PLDα1-produced phosphatidic acid is MAP65-1, a microtubule crosslinker which contains motifs for phosphatidic acid binding outside its carboxylterminal microtubule binding domain (Zhang et al, 2012 ).…”

CRK2 Enhances Salt Tolerance by Regulating Callose Deposition in Connection with PLDα1

“…These enzymes cleave phospholipids to produce PA and a free head group. PLD, along with its product PA, has been linked to a wide range of cellular processes in eukaryotic cells, including endocytosis and vesicle trafficking (Shen et al, 2001;Koch et al, 2004;Lee et al, 2006;Thakur et al, 2016), membrane composition and microdomains (Faraudo and Travesset, 2007), and microtubule and cytoskeletal dynamics (Zhang et al, 2012(Zhang et al, , 2017. Twelve PLD genes are present in Arabidopsis, of which PLDa1 is the major isoform (Pappan et al, 1997a(Pappan et al, , 1997b(Pappan et al, , 1998Qin et al, 1997;Wang and Wang, 2001;Qin and Wang, 2002).…”

CRK2 enhances salt tolerance in Arabidopsis thaliana by regulating endocytosis and callose deposition in connection with PLDα1

“…S. Lee et al, 2006;Shen et al, 2001;Thakur et al, 2016), membrane composition and microdomains (Faraudo & Travesset, 2007), and microtubule and cytoskeletal dynamics (Q. Zhang et al, 2012Zhang et al, , 2017. Twelve PLD genes are present in Arabidopsis, of which PLDα1 is the major isoform (Pappan et al, 1998;Pappan, Qin, et al, 1997;C.…”