Characterization of a ubiquitous expressed gene family encoding polygalacturonase in Arabidopsis thaliana

Torki, Moez; Mandaron, Paul; Mache, Régis; Falconet, Denis

doi:10.1016/s0378-1119(99)00497-7

Cited by 84 publications

(80 citation statements)

References 26 publications

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“…PME action on a highly esterified HG is required before polygalacturonases can cleave effectively. Plant polygalacturonases occur in large multigene families, and members are likely to have a range of functions in plant growth and development although these are as yet uncertain (32,33). The generation of HG substrates susceptible to polygalacturonase cleavage is likely to be greatly influenced by PME activities.…”

Section: Discussionmentioning

confidence: 99%

Modulation of the Degree and Pattern of Methyl-esterification of Pectic Homogalacturonan in Plant Cell Walls

Willats

Orfila

Limberg³

et al. 2001

Journal of Biological Chemistry

552

415

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Homogalacturonan (HG) is a multifunctional pectic polysaccharide of the primary cell wall matrix of all land plants. HG is thought to be deposited in cell walls in a highly methyl-esterified form but can be subsequently de-esterified by wall-based pectin methyl esterases (PMEs) that have the capacity to remove methyl ester groups from HG. Plant PMEs typically occur in multigene families/isoforms, but the precise details of the functions of PMEs are far from clear. Most are thought to act in a processive or blockwise fashion resulting in domains of contiguous de-esterified galacturonic acid residues. Such de-esterified blocks of HG can be crosslinked by calcium resulting in gel formation and can contribute to intercellular adhesion. We demonstrate that, in addition to blockwise de-esterification, HG with a non-blockwise distribution of methyl esters is also an abundant feature of HG in primary plant cell walls. A partially methyl-esterified epitope of HG that is generated in greatest abundance by non-blockwise de-esterification is spatially regulated within the cell wall matrix and occurs at points of cell separation at intercellular spaces in parenchymatous tissues of pea and other angiosperms. Analysis of the properties of calcium-mediated gels formed from pectins containing HG domains with differing degrees and patterns of methyl-esterification indicated that HG with a non-blockwise pattern of methyl ester group distribution is likely to contribute distinct mechanical and porosity properties to the cell wall matrix. These findings have important implications for our understanding of both the action of pectin methyl esterases on matrix properties and mechanisms of intercellular adhesion and its loss in plants.

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Section: Discussionmentioning

confidence: 99%

Modulation of the Degree and Pattern of Methyl-esterification of Pectic Homogalacturonan in Plant Cell Walls

Willats

Orfila

Limberg³

et al. 2001

Journal of Biological Chemistry

552

415

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“…However, little is known about the enzyme activity and substrate specificity of most plant PGs. There are at least 69 and 59 predicted PGs in the Arabidopsis and rice (Oryza sativa) genomes, respectively Gonzá lez-Carranza et al, 2007), and it has been suggested that one group of related PGs tend to be expressed in flowers and flower buds, while PGs expressed in vegetative tissues generally belong to other groups (Torki et al, 2000;. The implication is that the diverse potential physiological roles of PGs may be a consequence of differential expression in specific tissues rather than or in addition to differences in enzyme substrate specificity.…”

Section: Introductionmentioning

confidence: 99%

ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1), ADPG2, and QUARTET2 Are Polygalacturonases Required for Cell Separation during Reproductive Development inArabidopsis

et al. 2009

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Cell separation is thought to involve degradation of pectin by several hydrolytic enzymes, particularly polygalacturonase (PG). Here, we characterize an activation tagging line with reduced growth and male sterility caused by increased expression of a PG encoded by QUARTET2 (QRT2). QRT2 is essential for pollen grain separation and is part of a small family of three closely related endo-PGs in the Arabidopsis thaliana proteome, including ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1) and ADPG2. Functional assays and complementation experiments confirm that ADPG1, ADPG2, and QRT2 are PGs. Genetic analysis demonstrates that ADPG1 and ADPG2 are essential for silique dehiscence. In addition, ADPG2 and QRT2 contribute to floral organ abscission, while all three genes contribute to anther dehiscence. Expression analysis is consistent with the observed mutant phenotypes. INDEHISCENT (IND) encodes a putative basic helix-loop-helix required for silique dehiscence, and we demonstrate that the closely related HECATE3 (HEC3) gene is required for normal seed abscission and show that IND and HEC3 are required for normal expression of ADPG1 in the silique dehiscence zone and seed abscission zone, respectively. We also show that jasmonic acid and ethylene act together with abscisic acid to regulate floral organ abscission, in part by promoting QRT2 expression. These results demonstrate that multiple cell separation events, including both abscission and dehiscence, require closely related PG genes.

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“…Plants, instead, utilize PG in processes such as growth (2), fruit softening (3), root formation (4), organ abscission (5), and pollen development (6). The complex role of PG in the dynamics of the plant cell wall is suggested by the presence of large PG gene families in plant genomes; e.g., more than 50 putative PGs have been identified in the small plant Arabidopsis thaliana (7). Fungal PGs with an endo mode of action catalyze the fragmentation and solubilization of pectic polymers by cleaving the internal bonds of homogalacturonan, which is the constituent of the ''smooth region'' of pectin.…”

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confidence: 99%

Structural requirements of endo polygalacturonase for the interaction with PGIP (polygalacturonase-inhibiting protein)

Federici

Caprari

Mattei

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

135

129

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To invade a plant tissue, phytopathogenic fungi produce several cell wall-degrading enzymes; among them, endopolygalacturonase (PG) catalyzes the fragmentation and solubilization of homogalacturonan. Polygalacturonase-inhibiting proteins (PGIPs), found in the cell wall of many plants, counteract fungal PGs by forming specific complexes with them. We report the crystal structure at 1.73 Å resolution of PG from the phytopathogenic fungus Fusarium moniliforme (FmPG). The structure of FmPG was useful to study the mode of interaction of the enzyme with PGIP-2 from Phaseolus vulgaris. Several amino acids of FmPG were mutated, and their contribution to the formation of the complex with PGIP-2 was investigated by surface plasmon resonance. The residues Lys-269 and Arg-267, located inside the active site cleft, and His-188, at the edge of the active site cleft, are critical for the formation of the complex, which is consistent with the observed competitive inhibition of the enzyme played by PGIP-2. The replacement of His-188 with a proline or the insertion of a tryptophan after position 270, variations that both occur in plant PGs, interferes with the formation of the complex. We suggest that these variations are important structural requirements of plant PGs to prevent PGIP binding.

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Characterization of a ubiquitous expressed gene family encoding polygalacturonase in Arabidopsis thaliana

Cited by 84 publications

References 26 publications

Modulation of the Degree and Pattern of Methyl-esterification of Pectic Homogalacturonan in Plant Cell Walls

Modulation of the Degree and Pattern of Methyl-esterification of Pectic Homogalacturonan in Plant Cell Walls

ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1), ADPG2, and QUARTET2 Are Polygalacturonases Required for Cell Separation during Reproductive Development inArabidopsis

Structural requirements of endo polygalacturonase for the interaction with PGIP (polygalacturonase-inhibiting protein)

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