A glossary of plant cell structures: Current insights and future questions

Abstract

In this glossary of plant cell structures, we asked experts to summarize a present-day view of plant organelles and structures, including a discussion of outstanding questions. In the following short reviews, the authors discuss the complexities of the plant cell endomembrane system, exciting connections between organelles, novel insights into peroxisome structure and function, dynamics of mitochondria, and the mysteries that need to be unlocked from the plant cell wall. These discussions are focused through a lens of new microscopy techniques. Advanced imaging has uncovered unexpected shapes, dynamics, and intricate membrane formations. With a continued focus in the next decade, these imaging modalities coupled with functional studies are sure to begin to unravel mysteries of the plant cell.

Phosphatidylinositol 4‐phosphate: a key determinant of plasma membrane identity and function in plants

“…The exact function of PI4P in the Golgi/TGN also remains poorly understood. Given the specificities of the plant TGN (Kang et al ., 2022), it is likely that PI4P may have unique functions in this compartment.…”

“…Phosphatidylinositol 4‐phosphate is also required for the localization of tethering proteins involved in the establishment of membrane contact sites (Noack & Jaillais, 2020; Kang et al ., 2022) (Table 1). SYNAPTOTAGMIN1 (SYT1) is a tethering protein that is embedded in the ER membrane via transmembrane domains, and which contacts the plasma membrane through lipid‐binding C2 domains (Pérez‐Sancho et al ., 2015) (Fig.…”

“…PI4P is also required for the localization of MULTIPLE C2 DOMAIN AND TRANSMEMBRANE PROTEINs (MCTP) (Brault et al ., 2019). MCTPs tether the ER to the plasma membrane within plasmodesmata, which are membrane‐lined pores that connect plant cells (Kang et al ., 2022). Following pharmacological inhibition of PI4P, MCTP4 no longer accumulates in plasmodesmata (Brault et al ., 2019).…”

SLDP and LIPA mediate lipid droplet-plasma membrane tethering in Arabidopsis thaliana

“…While plant LD research has yielded a number of significant advancements in recent years (Lundquist et al, 2020;Ischebeck et al, 2020;Kang et al, 2021), many important questions related to plant LD biology remain unanswered, including if and how they interact with other organelles and subcellular structures. Here, we took advantage of the recent proteomics-based identification of several novel LDassociated proteins (Kretzschmar et al, 2020) and characterised two members of the plant-specific SLDP family, SLDP1 and SLDP2.…”

An Update on the Key Factors Required for Plant Golgi Structure Maintenance

“…In this review, we summarize the up-to-date knowledge on genetic evidences for Golgi maintenance in plants, with a focus on protein elements in intra-Golgi trafficking. For a detailed description and discussion on plant Golgi ultrastructure, please refer to these excellent reviews ( Robinson, 2020 ; Kang et al, 2022 ).…”