<i>Arabidopsis PLD</i>ζ<i>2</i>Regulates Vesicle Trafficking and Is Required for Auxin Response

Li, Gang; Hou, Xue

doi:10.1105/tpc.106.041426

Cited by 201 publications

(160 citation statements)

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“…Thus, for a particular cell file within the arabidopsis root, the TD can also be defined as the region where cells endoreduplicate and continue elongating at the same rate as in the PD. It has also been shown that phospholipase Df2, involved in vesicle trafficking, is strongly expressed in the transition zone (Li and Xue, 2007;Mancuso et al, 2007). The MSC analysis used here clearly shows that before the onset of rapid elongation all cells within a file, irrespective of the tissue type, are distributed in two subsets separated by an identifiable transition: those in the PD and those in the TD.…”

Section: Discussionmentioning

confidence: 52%

Longitudinal zonation pattern inArabidopsisroot tip defined by a multiple structural change algorithm

Pacheco-Escobedo

Ivanov

Ransom-Rodríguez

et al. 2016

Ann Bot

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Background and Aims The Arabidopsis thaliana root is a key experimental system in developmental biology. Despite its importance, we are still lacking an objective and broadly applicable approach for identification of number and position of developmental domains or zones along the longitudinal axis of the root apex or boundaries between them, which is essential for understanding the mechanisms underlying cell proliferation, elongation and differentiation dynamics during root development.Methods We used a statistics approach, the multiple structural change algorithm (MSC), for estimating the number and position of developmental transitions in the growing portion of the root apex. Once the positions of the transitions between domains and zones were determined, linear models were used to estimate the critical size of dividing cells (L critD ) and other parameters.Key Results The MSC approach enabled identification of three discrete regions in the growing parts of the root that correspond to the proliferation domain (PD), the transition domain (TD) and the elongation zone (EZ). Simultaneous application of the MSC approach and G2-to-M transition (CycB1;1DB:GFP) and endoreduplication (pCCS52A1:GUS) molecular markers confirmed the presence and position of the TD. We also found that the MADS-box gene XAANTAL1 (XAL1) is required for the wild-type (wt) PD increase in length during the first 2 weeks of growth. Contrary to wt, in the xal1 loss-of-function mutant the increase and acceleration of root growth were not detected. We also found alterations in L critD in xal1 compared with wt, which was associated with longer cell cycle duration in the mutant.Conclusions The MSC approach is a useful, objective and versatile tool for identification of the PD, TD and EZ and boundaries between them in the root apices and can be used for the phenotyping of different genetic backgrounds, experimental treatments or developmental changes within a genotype. The tool is publicly available at www.ibiologia.com.mx/MSC_analysis.

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Section: Discussionmentioning

confidence: 52%

Longitudinal zonation pattern inArabidopsisroot tip defined by a multiple structural change algorithm

Pacheco-Escobedo

Ivanov

Ransom-Rodríguez

et al. 2016

Ann Bot

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“…In this sense, with regards to the role of PLD2 under the initial stage of phosphate deprivation and PLD2 tonoplast localization (12,22,33,40,41), PA produced by PLD2 could be a switch related to phosphate sensing. Formation of prokaryotic PA could also be important for MGD1 activity.…”

Section: Discussionmentioning

confidence: 99%

Activation of the Chloroplast Monogalactosyldiacylglycerol Synthase MGD1 by Phosphatidic Acid and Phosphatidylglycerol

Dubots

Audry

Yamaryo

et al. 2010

Journal of Biological Chemistry

102

106

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One of the major characteristics of chloroplast membranes is their enrichment in galactoglycerolipids, monogalactosyldiacylglycerol (MGDG), and digalactosyldiacylglycerol (DGDG), whereas phospholipids are poorly represented, mainly as phosphatidylglycerol (PG). All these lipids are synthesized in the chloroplast envelope, but galactolipid synthesis is also partially dependent on phospholipid synthesis localized in non-plastidial membranes. MGDG synthesis was previously shown essential for chloroplast development. In this report, we analyze the regulation of MGDG synthesis by phosphatidic acid (PA), which is a general precursor in the synthesis of all glycerolipids and is also a signaling molecule in plants. We demonstrate that under physiological conditions, MGDG synthesis is not active when the MGDG synthase enzyme is supplied with its substrates only, i.e. diacylglycerol and UDP-gal. In contrast, PA activates the enzyme when supplied. This is shown in leaf homogenates, in the chloroplast envelope, as well as on the recombinant MGDG synthase, MGD1. PG can also activate the enzyme, but comparison of PA and PG effects on MGD1 activity indicates that PA and PG proceed through different mechanisms, which are further differentiated by enzymatic analysis of point-mutated recombinant MGD1s. Activation of MGD1 by PA and PG is proposed as an important mechanism coupling phospholipid and galactolipid syntheses in plants.Chloroplast membrane lipids are mostly composed of nonphosphorous galactoglycerolipids i.e. monogalactosyldiacylglycerol (MGDG) 2 and digalactosyldiacylglycerol (DGDG) that represent more than 50 and 30% of thylakoid lipids, respectively. Phosphatidylglycerol is the main phospholipid in plastids, representing about 10% of thylakoid lipids. Each of those glycerolipid classes is represented by a range of molecular species differing in the acyl composition at sn-1 and sn-2 positions of the glycerol backbone. Based on the model of cyanobacterial lipids, the prokaryotic type of glycerolipids contains a 16-carbon fatty acid at the sn-2 position of glycerol. The eukaryotic type contains an 18-carbon fatty acid at the sn-2 position. Some plants, such as Arabidopsis or spinach, have both prokaryoticand eukaryotic-type MGDG, whereas other plants, such as pea or cucumber, have only eukaryotic-type MGDG. DGDG is mostly of eukaryotic type in all plants. Chloroplast PG contains exclusively a prokaryotic-type DAG moiety in contrast to nonplastidial PG. These different chloroplast lipids are assembled in the chloroplast envelope (1). Most enzymes have now been identified, but their functioning and regulation remain largely unknown.MGDG is synthesized by MGDG synthase (MGD), which transfers galactose from UDP-gal to DAG. In Arabidopsis, there are three MGDG synthases, and among them, MGD1, is necessary for synthesis of galactolipids and for development of photosynthetic membranes (2, 3). MGD1 utilizes DAG derived from two main sources, either from a DAG de novo synthesized in plastid envelope by double acylation of glycer...

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“…Although many pieces of evidence have indicated the crosstalk between the PI signaling pathway and auxin signaling pathway via regulation of auxin homeostasis or auxin transport [12,42,[49][50][51], the potential link of PIP5K with auxin-related processes has not yet been directly investigated. Here we report on the functional characterization of Arabidopsis PIP5K2, which is expressed in various tissues and whose expression is enhanced by exogenous auxin.…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

et al. 2011

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Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5) P 2 ) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k2 shows reduced lateral root formation, which could be recovered with exogenous auxin, and interestingly, delayed root gravity response that could not be recovered with exogenous auxin. Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2. In addition, analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P 2 reduction, which hence results in suppressed cycling of PIN proteins (PIN2 and 3), and delayed redistribution of PIN2 and auxin under gravistimulation in pip5k2 roots. On the contrary, PtdIns(4,5) P 2 significantly enhanced the vesicle trafficking and cycling of PIN proteins. These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response, and reveal a critical role of PIP5K2/PtdIns(4,5)P 2 in root development through regulation of PIN proteins, providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response, and new insights into the control of polar auxin transport.

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Arabidopsis PLDζ2Regulates Vesicle Trafficking and Is Required for Auxin Response

Cited by 201 publications

References 84 publications

Longitudinal zonation pattern inArabidopsisroot tip defined by a multiple structural change algorithm

Longitudinal zonation pattern inArabidopsisroot tip defined by a multiple structural change algorithm

Activation of the Chloroplast Monogalactosyldiacylglycerol Synthase MGD1 by Phosphatidic Acid and Phosphatidylglycerol

Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

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