RRC ID 78634
Author Hocq L, Habrylo O, Sénéchal F, Voxeur A, Pau-Roblot C, Safran J, Fournet F, Bassard S, Battu V, Demailly H, Tovar JC, Pilard S, Marcelo P, Savary BJ, Mercadante D, Njo MF, Beeckman T, Boudaoud A, Gutierrez L, Pelloux J, Lefebvre V.
Title Mutation of AtPME2, a pH-Dependent Pectin Methylesterase, Affects Cell Wall Structure and Hypocotyl Elongation.
Journal Plant Cell Physiol
Abstract Pectin methylesterases (PMEs) modify homogalacturonan's chemistry and play a key role in regulating primary cell wall mechanical properties. Here, we report on Arabidopsis AtPME2, which we found to be highly expressed during lateral root emergence and dark-grown hypocotyl elongation. We showed that dark-grown hypocotyl elongation was reduced in knock-out mutant lines as compared to the control. The latter was related to the decreased total PME activity as well as increased stiffness of the cell wall in the apical part of the hypocotyl. To relate phenotypic analyses to the biochemical specificity of the enzyme, we produced the mature active enzyme using heterologous expression in Pichia pastoris and characterized it through the use of a generic plant PME antiserum. AtPME2 is more active at neutral compared to acidic pH, on pectins with a degree of 55-70% methylesterification. We further showed that the mode of action of AtPME2 can vary according to pH, from high processivity (at pH8) to low processivity (at pH5), and relate these observations to the differences in electrostatic potential of the protein. Our study brings insights into how the pH-dependent regulation by PME activity could affect the pectin structure and associated cell wall mechanical properties.
Volume 65(2)
Pages 301-318
Published 2024-2-15
DOI 10.1093/pcp/pcad154
PII 7513042
PMID 38190549
MeSH Arabidopsis* / metabolism Carboxylic Ester Hydrolases* Cell Wall / metabolism Hydrogen-Ion Concentration Hypocotyl* / genetics Hypocotyl* / metabolism Mutation / genetics Pectins / metabolism
Arabidopsis / Cultured plant cells, genes pda01692