Analysis of regulatory networks underlying morphogenesis of leaf epidermis pavement cells
Final Report Abstract
Plant cell shape formation relies on the intricate interplay between extracellular cell walls, intracellular cytoskeletal elements, and the plasma membrane. The precise coordination of these components orchestrates the diverse morphologies crucial for tissue function. In many plant species, leaf epidermis pavement cells are characterized by highly complex jigsaw puzzle-like shapes with alternating lobes and indentations in their anticlinal walls that develop from simple-shaped polyhedral cells. Understanding the mechanisms underlying morphogenesis of epidermis pavement cells, which exemplify highly anisotropic growth, thus has gained great interest in developmental biology. Previously, we identified members of the plant-specific IQ67 Domain (IQD) protein family as novel regulators of pavement cell shape in Arabidopsis thaliana. IQDs share hallmarks of cellular scaffolds with proposed functions in macromolecular complex assemblies at the microtubule cytoskeleton. The composition and architecture of IQD-assembled complexes and their modes of function, however, are largely unknown. In this project, we identified Kinesin Light Chain-Related (KLCR) proteins, also termed Cellulose Microtubule Uncoupling (CMU) as in planta interactors of IQDs and showed that IQD2-KLCR1 modules control the morphogenesis of leaf epidermis pavement cells. Using seed mucilage as a model for genetic analysis of cell wall composition, we uncovered functions of IQD9-KLCR1 in orchestration of cellulose patterning. We further showed that functions of IQDs in shape regulation are conserved across different species, as evidenced by defects in cell and fruit shape in tomato (Solanum lycopersicum) mutants with altered IQD expression. These functions involve interactions with MAP70 proteins, potentially facilitating differential tissue- and developmental control of the microtubule cytoskeleton. Collectively, we broadened our understanding of IQD-assembled complexes by the identification of novel interactors and provide first mechanistic insights into cellular functions in microtubule organization and cellulose deposition. Our results provide a framework for future mechanistic studies aimed at elucidating the molecular structure of IQD-assembled complexes and, more generally, for identification of principles underlying shape establishment in plants.
Publications
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User-friendly assessment of pavement cell shape features with PaCeQuant: Novel functions and tools. Methods in Cell Biology, 349-363. Elsevier.
Poeschl Y.; Möller B.; Müller L. & Bürstenbinder K.
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The Morphological Diversity of Plant Organs: Manipulating the Organization of Microtubules May Do the Trick. Frontiers in Cell and Developmental Biology, 9.
Bao, Zhiru; Xu, Zhijing; Zang, Jingze; Bürstenbinder, Katharina & Wang, Pengwei
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Microtubule‐associated IQD9 orchestrates cellulose patterning in seed mucilage. New Phytologist, 235(3), 1096-1110.
Yang, Bo; Stamm, Gina; Bürstenbinder, Katharina & Voiniciuc, Cătălin
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Microtubule-associated protein SlMAP70 interacts with IQ67-domain protein SlIQD21a to regulate fruit shape in tomato. The Plant Cell, 35(12), 4266-4283.
Bao, Zhiru; Guo, Ye; Deng, Yaling; Zang, Jingze; Zhang, Junhong; Deng, Yingtian; Ouyang, Bo; Qu, Xiaolu; Bürstenbinder, Katharina & Wang, Pengwei
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Origin and Evolution of IQD Scaffolds and Assembled Protein Complexes in Plant Cell Division.
Dahiya, Pradeep; Haluška, Samuel; Buhl, Jonas; Kölling, Malte; Papsdorf, Sven; Zehnich, Daniela; Machalett, Klara; Pfeiffer, Pauline; Stamm, Gina; Potocký, Martin & Bürstenbinder, Katharina
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Quantitative Analysis of Microtubule Organization in Leaf Epidermis Pavement Cells. Methods in Molecular Biology, 43-61. Springer US.
Klemm, Sandra; Buhl, Jonas; Möller, Birgit & Bürstenbinder, Katharina
