Reduced pectin content of cell walls prevents stress-induced root cell elongation in Arabidopsis

Abstract

The primary cell walls of plants provide mechanical strength while maintaining the flexibility needed for cell extension growth. Cell extension involves loosening the bonds between cellulose microfibrils, hemicelluloses and pectins. Pectins have been implicated in this process, but it remains unclear if this depends on the abundance of certain pectins, their modifications and/or structure. Here, cell wall-related mutants of the model plant Arabidopsis thaliana were characterized by biochemical and immunohistochemical methods and Fourier-transform infrared microspectroscopy. Mutants with reduced pectin or hemicellulose contents showed no root cell elongation in response to simulated drought stress, in contrast to wild-type plants or mutants with reduced cellulose content. While no association was found between the degrees of pectin methylesterification and cell elongation, cell wall composition analysis suggested an important role of the pectin Rhamnogalacturonan II (RGII) that was corroborated in experiments with the RGII-modifying chemical 2β-deoxy-Kdo. Results were complemented by expression analysis of cell wall synthesis genes and the microscopic analysis of cell wall porosity. It is concluded that a certain amount of pectin is necessary for stress-induced root cell elongation and hypotheses regarding the mechanistic basis of this result are formulated.

Cellulose synthase‐like protein OsCSLD4 plays an important role in the response of rice to salt stress by mediating abscisic acid biosynthesis to regulate osmotic stress tolerance

“…The rapid alkalinization factors (RALFs) are a type of small signalling peptides. RALFs play important roles in growth and development, and are involved in stress responses (Liu et al, 2021b;Murphy and De Smet, 2014). In Arabidopsis, the constitutive expression of AtRALFL8 increased transgenic plant susceptibility to drought stress (Atkinson and Lilley, 2013).…”

“…Plant cell walls not only determine cell shape and provide structural support, but they also act as the front line of various environmental stresses (Doblin and Pettolino, 2010;Liu et al, 2021a;Tenhaken, 2014;Voxeur and H€ ofte, 2016). Plant cell wall polysaccharides exhibit a striking variety in composition in accordance with environmental conditions, and therefore, there is a close relationship between the variety of plant cell wall polysaccharide compositions and the response of plants to environmental stresses (Corrêa-Ferreira et al, 2019;Doblin et al, 2010;Houston et al, 2016;Lenk et al, 2019;Liu et al, 2021b;Yang et al, 2021;Zhang et al, 2021).…”

“…Cell wall polysaccharides also play important roles in plant responses to environmental stresses (Corrêa-Ferreira et al, 2019;Houston et al, 2016;Lenk et al, 2019;Liu et al, 2021b;Tenhaken, 2014;Yang et al, 2021). Salinity stress is one of the most widespread abiotic stresses and has a serious threat to global food security.…”

OsDMI3‐mediated OsUXS3 phosphorylation improves oxidative stress tolerance by modulating OsCATB protein abundance in rice

“…Cell wall biosynthesis‐related enzymes play important and complex roles in plant responses to environmental stresses (Zhu et al, 2010; Zhang et al, 2016; Corrêa‐Ferreira et al, 2019; Lenk et al, 2019; Liu et al, 2021; Yan et al, 2021; Zhao et al, 2021). Besides modulating the biosynthesis of cell wall polysaccharides, several enzymes have been reported to be involved in stress response by regulating ROS scavenging.…”

“…Cytosolic UXSs contribute to xylan biosynthesis more substantially than their Golgi‐localized UXS counterparts (Kuang et al, 2016; Zhong et al, 2017). As the majority of work on cell wall polysaccharide‐related enzymes has focused on their roles in stress responses, little is known about the possible involvement of UXS in plant tolerance mechanisms (Tenhaken., 2015; Houston et al, 2016; Han et al, 2017; Lenk et al, 2019; Liu et al, 2021; Yan et al, 2021). In this study, we show that the cytosolic enzyme OsUXS3 is a novel phosphorylation target of OsDMI3 in response to oxidative stress.…”