Identification of pectin methylesterase 3 as a basic pectin methylesterase isoform involved in adventitious rooting in Arabidopsis thaliana

Abstract

Summary• Here, we focused on the biochemical characterization of the Arabidopsis thaliana pectin methylesterase 3 gene (AtPME3; At3g14310) and its role in plant development.• A combination of biochemical, gene expression, Fourier transform-infrared (FT-IR) microspectroscopy and reverse genetics approaches were used.• We showed that AtPME3 is ubiquitously expressed in A. thaliana, particularly in vascular tissues. In cell wall-enriched fractions, only the mature part of the protein was identified, suggesting that it is processed before targeting the cell wall. In all the organs tested, PME activity was reduced in the atpme3-1 mutant compared with the wild type. This was related to the disappearance of an activity band corresponding to a pI of 9.6 revealed by a zymogram. Analysis of the cell wall composition showed that the degree of methylesterification (DM) of galacturonic acids was affected in the atpme3-1 mutant. A change in the number of adventitious roots was found in the mutant, which correlated with the expression of the gene in adventitious root primordia.• Our results enable the characterization of AtPME3 as a major basic PME isoform in A. thaliana and highlight its role in adventitious rooting.

Requirement for Pectin Methyl Esterase and Preference for Fragmented over Native Pectins for Wall-associated Kinase-activated, EDS1/PAD4-dependent Stress Response in Arabidopsis

“…Alternative interpretations of the increased response to OGs by pme3/pme3 are also possible, including an increased porosity of the wall in a pme3/pme3 mutant such that OGs have more access to membrane receptors. This is less likely because, first, few structural differences in the walls were detected in the pme3/pme3 mutant (29), and second, treatment of WT seedlings with fluorescent OGs results in a rapid (minutes) and apparent ubiquitous coating of the plasma membrane (data not shown), and the OG treatment given here to detect the transcriptional response was 3 h. It was also observed that methyl esterified OGs had no ability to induce the stress response as assayed by the induction of FADlox transcription. 3 Indeed, most pectinases expressed by pathogens prefer as targets de-esterified pectins (13), and subsequently, the predominant OGs generated upon infection are de-esterified.…”

“…We therefore asked if the WAK2cTAP phenotype was affected by a mutation in the most abundantly expressed pectin methyl esterase, PME3 (29). Null alleles of this locus lead to altered branching and root growth, but little effect on leaf morphology and size has been reported (29). Plants at the seedling and rosette stage homozygous for pme3 and WAK2cTAP appear to have a wild type morphology ( Fig.…”

“…In addition, WAKs appear to have a higher affinity for de-esterified than for esterified pectin in vitro. We therefore asked if the WAK2cTAP phenotype was affected by a mutation in the most abundantly expressed pectin methyl esterase, PME3 (29). Null alleles of this locus lead to altered branching and root growth, but little effect on leaf morphology and size has been reported (29).…”

PECTIN METHYLESTERASE48 Is Involved in Arabidopsis Pollen Grain Germination

“…The regulation of the DM of HG has been implicated in many aspects of plant development (Wolf et al, 2009a), including cell adhesion (Tieman and Handa, 1994;Wen et al, 1999;Mollet et al, 2000;Bouton et al, 2002;Mouille et al, 2007;Durand et al, 2009), adventitious rooting (Guénin et al, 2011), primordia emergence at the shoot apical meristem (Peaucelle et al, 2008(Peaucelle et al, , 2011, fruit ripening (Brummell and Harpster, 2001;Phan et al, 2007), and plant defense (Bethke et al, 2014). Although data have shown an important role for Figure 5.…”

Analysis of LuPME3, a pectin methylesterase from Linum usitatissimum, revealed a variability in PME proteolytic maturation

“…These antibodies were also shown to specifically recognize the Arabidopsis AtPME3 ortholog. 5 To gain insights into the role of LuPME3 in flax, cell wallenriched protein extracts from plantlets were separated by isolectric focusing (IEF) and then submitted to a PME activity assay on gel (zymogram) or to protein gel blot analysis. Flax seedlings were grown at 25°C for 3 d in the dark, then under light for 1, 7 and 13 d. Epicotyls (7 and 13 d only), cotyledons, hypocotyls and roots were collected and their cell wall proteins extracted.…”