improve def phragmoplast

[ValWood]

Existing Fibrous structure (light microscope view) that arises between the daughter nuclei at telophase and within which the initial partition (cell plate), dividing the mother cell in two (cytokinesis), is formed. Appears at first as a spindle connected to the two nuclei, but later spreads laterally in the form of a ring. Consists of microtubules.

https://en.wikipedia.org/wiki/Phragmoplast The phragmoplast is a plant cell specific structure that forms during late cytokinesis. It serves as a scaffold for cell plate assembly and subsequent formation of a new cell wall separating the two daughter cells. The phragmoplast can only be observed in Phragmoplastophyta,

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518215/#:~:text=The%20cell%20plate%20is%20synthetized,transition%20from%20anaphase%20to%20telophase. The cell plate is synthetized by a specialized structure called the phragmoplast, which consists of microtubules, actin filaments, membrane compartments and associated proteins. The phragmoplast forms between daughter nuclei during the transition from anaphase to telophase.

[ValWood]

Suggest The phragmoplast is a plant cell specific cytoplasmic actin and microtubule-based structure that serves as a scaffold for cell plate assembly and the formation of a new cell wall during late cytokinesis.

• [x] Also add taxon constraint: only in Viridiplantae

[ValWood]

@tberardini does this sound OK?

[ValWood]

Also, should phragmoplast](https://github.com/geneontology/go-ontology/issues/24426#top) have "cytoskeleton" as a part_of parent?

[tberardini]

Slight tweak:

The phragmoplast is a plant cell specific cytoplasmic actin and microtubule-based structure that serves as a scaffold for cell plate assembly and the formation of a new cell wall between two daughter cells during late cytokinesis.

If 'spindle' is part_of 'microtubule cytoskeleton', then I suppose that 'phragmoplast' should be part_of cytoskeleton.

More background: https://www.sciencedirect.com/topics/medicine-and-dentistry/phragmoplast

[ValWood]

The phragmoplast is a plant cell specific cytoplasmic secretory module consisting of actin filaments, microtubules, membrane compartments and other structures to facilitate plate assembly and the formation of a new cell wall during late cytokinesis. PMID:29074579, PMID:28943203

[pgaudet]

Nice defintion from Plant Cytokinesis: Terminology for Structures and Processes

Structure composed of cytoskeletal polymers, membranes, and associated cytosolic proteins that functions as the focused secretory module for assembling the cell plate.

[ValWood]

tweak to: The phragmoplast is a plant cell specific cytoplasmic structure composed of cytoskeletal polymers, membranes, and associated cytosolic proteins that functions as the focused secretory module for assembling the cell plate. PMID: 28943203