Abstract
Cortical microtubules guide the direction and deposition of cellulose microfibrils to build the cell wall, which in turn influences cell expansion and plant morphogenesis. In the model plant Arabidopsis thaliana (Arabidopsis), petal is a relatively simple organ that contains distinct epidermal cells, such as specialized conical cells in the adaxial epidermis and relatively flat cells with several lobes in the abaxial epidermis. In the past two decades, the Arabidopsis petal has become a model experimental system for studying cell expansion and organ morphogenesis, because petals are dispensable for plant growth and reproduction. Recent advances have expanded the role of microtubule organization in modulating petal anisotropic shape formation and conical cell shaping during petal morphogenesis. Here, we summarize recent studies showing that in Arabidopsis, several genes, such as SPIKE1, Rho of plant (ROP) GTPases, and IPGA1, play critical roles in microtubule organization and cell expansion in the abaxial epidermis during petal morphogenesis. Moreover, we summarize the live-confocal imaging studies of Arabidopsis conical cells in the adaxial epidermis, which have emerged as a new cellular model. We discuss the microtubule organization pattern during conical cell shaping. Finally, we propose future directions regarding the study of petal morphogenesis and conical cell shaping.
Highlights
Plant microtubules exhibit a highly dynamic network and play pivotal roles in cell proliferation, cell expansion, and shape formation during plant development [1,2]
Microtubules are tethered to the plasma membrane, referred to as cortical microtubules, which serve as tracks for plasma membrane-localized cellulose synthase complexes (CSCs) and thereby guide the direction and deposition of cellulose microfibrils [3,4,5,6]
Plant cell expansion is largely defined by cell wall anisotropy, which is correlated with the orientation of cellulose microfibrils [7,8,9,10,11,12]
Summary
Plant microtubules exhibit a highly dynamic network and play pivotal roles in cell proliferation, cell expansion, and shape formation during plant development [1,2]. Arabidopsis petals serve as a good experimental model system to investigate the molecular and genetic mechanisms regulating plant cell expansion and organ morphogenesis [16,17]. Molecular and genetic studies in the past two decades have shown that a large number of regulators play critical roles in petal growth and development [21,22,23,24,25,26,27,28,29,30,31,32,33]. More than 25 years ago, microtubules have been shown to correlate with petal epidermal cell morphogenesis [34] Despite this progress, the mechanisms by which the petal grows into its final anisotropic shape remain to be further understood. We propose future directions for the study of petal morphogenesis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
