PIN Polarity Maintenance by the Cell Wall in Arabidopsis

Abstract

A central question in developmental biology concerns the mechanism of generation and maintenance of cell polarity, because these processes are essential for many cellular functions and multicellular development. In plants, cell polarity has an additional role in mediating directional transport of the plant hormone auxin that is crucial for multiple developmental processes. In addition, plant cells have a complex extracellular matrix, the cell wall, whose role in regulating cellular processes, including cell polarity, is unexplored. We have found that polar distribution of PIN auxin transporters in plant cells is maintained by connections between polar domains at the plasma membrane and the cell wall. Genetic and pharmacological interference with cellulose, the major component of the cell wall, or mechanical interference with the cell wall disrupts these connections and leads to increased lateral diffusion and loss of polar distribution of PIN transporters for the phytohormone auxin. Our results reveal a plant-specific mechanism for cell polarity maintenance and provide a conceptual framework for modulating cell polarity and plant development via endogenous and environmental manipulations of the cellulose-based extracellular matrix.

Leaf development and morphogenesis

“…Auxin induces these factors, and they thus partially mediate the effect of auxin on organ initiation (Braybrook and Peaucelle, 2013). Additionally, mechanical forces as well as the cell wall were shown to affect the levels and polar distribution of PIN1 within the cell (Feraru et al, 2011;Heisler et al, 2010;Nakayama et al, 2012). However, mechanical stress appears to affect microtubule orientation and PIN1 polarization in parallel, as disruption of microtubule polymerization did not affect organ initiation in the short term (Hamant et al, 2008;Heisler et al, 2010).…”

Cellulose Synthesis and Its Regulation

“…A mutation in CESA3 (repp3) has been associated with altered PIN polarity that is essential for auxin flow in plants (Feraru et al, 2011). Given the importance of auxin trafficking during embryogenesis, it is possible that the defects in embryogenesis seen in CESA1 mutants might, to some degree, result from altered auxin transport (Beeckman et al, 2002).…”

The use of FTIR spectroscopy to monitor modifications in plant cell wall architecture caused by cellulose biosynthesis inhibitors

“…6 The use of PCA in conjunction with FTIR spectroscopy has proved to be an important tool in the study of cell wall structure and composition heterogeneity in a species, 7,8 or among different species, 5,9-11 as well as in the identification and classification of mutants with altered cell wall compositions. 6,[12][13][14] This approach has been also very useful in the characterization of the modifications appearing in this kind of mutants [15][16][17][18][19][20] or in transgenic plants with altered cell walls 21 and in the modifications to cell wall composition induced by different biotic or abiotic stress factors.…”