Stomatal Complex Development and F-Actin Organization in Maize Leaf Epidermis Depend on Cellulose Synthesis

Abstract

Cellulose microfibrils reinforce the cell wall for morphogenesis in plants. Herein, we provide evidence on a series of defects regarding stomatal complex development and F-actin organization in Zea mays leaf epidermis, due to inhibition of cellulose synthesis. Formative cell divisions of stomatal complex ontogenesis were delayed or inhibited, resulting in lack of subsidiary cells and frequently in unicellular stomata, with an atypical stomatal pore. Guard cells failed to acquire a dumbbell shape, becoming rounded, while subsidiary cells, whenever present, exhibited aberrant morphogenesis. F-actin organization was also affected, since the stomatal complex-specific arrays were scarcely observed. At late developmental stages, the overall F-actin network was diminished in all epidermal cells, although thick actin bundles persisted. Taken together, stomatal complex development strongly depends on cell wall mechanical properties. Moreover, F-actin organization exhibits a tight relationship with the cell wall.

Cytoskeletal regulation of primary plant cell wall assembly

“…The resulting actin response occurred at forces and in time frames considerably smaller than those required for microtubules 152,153 . Furthermore, similar to microtubules, changes in cellulose synthesis and the cell wall also affect actin organization 34,154 . These findings raise the possibility of an actin-based sensory mechanism in plants that, similar to microtubules, perceives mechanical cues, for example due to pathogen invasion 155 , and responds by ensuring immediate vesicle supply of relevant material such as callose synthases to the sites of infection 156 .…”

Controlling the Gate: The Functions of the Cytoskeleton in Stomatal Movement

“…Emerging studies provide evidences indicating that the cytoskeleton, including actin filaments (AFs) and microtubules (MTs), is considered as an important factor involved in stomatal movement, possibly via affecting turgor pressure in guard cells ( Zhang and Fan, 2009 ; Khanna et al, 2014 ). The cytoskeleton participates in cell division and cell wall synthesis, which affect guard cell shape, structure, and mechanics ( Galatis and Apostolakos, 2004 ; Panteris et al, 2018 ; Woolfenden et al, 2018 ; Muroyama et al, 2020 ). MTs guide cellulose synthesis complexes and determine cellulose microfibril orientation, which might provide high tensile strength in guard cells during stomatal movement ( Woolfenden et al, 2018 ).…”

Beyond Microcystins: Cyanobacterial Extracts Induce Cytoskeletal Alterations in Rice Root Cells

“…F-actin was labeled with fluorescent phalloidin, according to [ 64 ], with slight modifications. F-actin in rice root tips was prestabilized with 300 μM m-maleimidobenzoyl- N -hydroxysuccinimide ester in PEM + 0.1% ( v / v ) Triton X-100 for 30 min in the dark and fixed with 4% ( w / v ) PFA in PEM + 5% ( v / v ) DMSO + 0.1% ( v / v ) Triton X-100 + DyLight 554-phalloidin (Cell Signaling Technology, Danvers, MA, USA) 1:400 for better F-actin preservation.…”