下胚轴
细胞壁
过程性
果胶
延伸率
化学
扩张素
生物化学
突变体
生物物理学
拟南芥
解聚
三叶草
细胞生物学
酶
生物
植物
基因表达
材料科学
有机化学
极限抗拉强度
聚合酶
基因
农学
冶金
作者
Ludivine Hocq,Olivier Habrylo,Fabien Sénéchal,Aline Voxeur,Corinne Pau-Roblot,Josip Safran,Françoise Fournet,Solène Bassard,Virginie Battu,Hervé Demailly,Jose C. Tovar,Serge Pilard,Paulo Marcelo,Brett J. Savary,Davide Mercadante,Maria Njo,Tom Beeckman,Arezki Boudaoud,Laurent Gutierrez,Jérôme Pelloux,Valérie Lefebvre
摘要
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.
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