meristematic cell and child terms: meristemoid/initial cell

[planteome-user]

Right now there is overlap between the terms meristermoid (PO:0000070) and initial cell (PO:0004011), and as a result, stomatal guard cell has develops from relations to both epidermal initial and meristemoid.

Although an initial cell is now defined as "a cell in a meristem...", in fact, neither child of initial cell (cambial initial or epidermal initial) is part of a meristem. Perhaps it would be better if initial cell was child of meristemoid.

Current definitions: meristematic cell: A cell synthesizing protoplasm and producing new cells by division and with only a primary cell wall. is_a plant cell, part_of meristem

meristemoid: A cell or a group of cells constituting an active locus of meristematic activity in a tissue composed of somewhat older, differentiating cells. is_a plant cell

initial cell: Cell in a meristem that by division gives rise to two cells one of which remains in the meristem, the other is added to the plant body. is_a meristematic cell. is_a meristematic cell

epidermal initial: A relatively unspecialized cell that will give rise to specialized cell types of the epidermis. is_a intial cell

Suggested definitions:

meristematic cell: okay as is, but change from part_of meristem to meristem has_part meristematic cell (since not all meristematic cells are part of a meristem -- we can discuss this)

meristemoid: A meristematic cell that is part of a portion of tissue that is composed mostly of somewhat older, differentiating cells.

initial cell: A meristemoid that by (uneven?) division gives rise to two cells, one of which remains meristematic, while the other is added to the plant body.

epidermal initial: An initial cell that is part of an epidermis and will give rise to specialized cell types of the epidermis.

New term: stomatal initial/stomatal meristemoid (child of initial cell): see separate tracker item: https://sourceforge.net/tracker/index.php?func=detail&aid=3112108&group\_id=76834&atid=835555

Reported by: rlwalls2008

Original Ticket: obo/plant-ontology-po-term-requests/272

[planteome-user]

Question: do we need separate terms for meristemoid and initial cell, or should they be synonyms?

Original comment by: rlwalls2008

[planteome-user]

My experience is that meristemoid is sort of limited to stomatal development.

Original comment by: dws409

[planteome-user]

At the POC meeting on 2-1-11, we merged meristermoid into initial cell. New definition: A meristematic cell that by division gives rise to two cells, one of which remains meristematic, while the other is added to the plant body. Comment: Initial cells are often part of a portion of tissue that is composed mostly of somewhat older, differentiating cells. The division of an initial cell is often uneven, with the smaller daughter cell remaining meristematic.

New definition of epidermal initial was accepted. Added synonym epidermal initial cell

Original comment by: rlwalls2008

[planteome-user]

• summary: meristemoid/initial cell --> meristematic cell and child terms: meristemoid/initial cell
• status: closed-fixed --> open
• assigned_to: Ramona Walls --> Laurel Cooper
• Priority: 5 --> 8

Original comment by: cooperl09

[planteome-user]

Question from Chris Mungall by email:

[Term] id: PO:0004010 name: meristematic cell namespace: plant_anatomy def: "A plant cell synthesizing protoplasm and producing new cells by division and with only a primary cell wall." [ISBN:0471245208] subset: CL xref: CL:0000034 is_a: PO:0009002 ! plant cell

The CL class is 'stem cell': def: "A relatively undifferentiated cell that retains the ability to divide and proliferate throughout life to provide progenitor cells that can differentiate into specialized cells." [GOC:tfm, MESH:A11.872]

Would you say the plant cell type is the equivalent for plants?

Original comment by: cooperl09

[planteome-user]

Do you mean that is a (plant) meristematic cell (PO:0004010) the same as a stem cell (CL:0000034)? If so, the answer is yes (more or less) and they are used interchangeably in the literature.

For example, from the recent paper by Machida et al 2013: "After germination, the SAM develops shoot organs and tissues by proliferation and differentiation of cells in peripheral regions, whereas the RAM differentiates several types of root tissues in proximal and distal directions to form the root proper and the root cap, respectively. Both meristems maintain the stem cell population by self-renewal. (http://pcp.oxfordjournals.org/content/54/3/295.extract).

And from Uchida et al, 2013: "Shoot apical meristems (SAMs), which are maintained at the tips of stems, are indeterminate structures and sources of stem cells from which all aerial organs are ultimately derived." http://pcp.oxfordjournals.org/content/54/3/343.abstract

I added the name "stem cell" as an exact synonym.

Original comment by: cooperl09

[planteome-user]

Note the syn "stem cell" is used for the child "initial cell"

This is a related synonym only, as initial cells are a special sub class of meristematic cells.

Original comment by: cooperl09

[planteome-user]

Moved to be is_a native plant cell and updated the def'n: See: [plant-ontology-po-term-requests:#586]

meristematic cell (PO:0004010): A native plant cell (PO:0025606) synthesizing protoplasm and producing new cells by division and with only a primary cell wall.

Added missing Xref: Updated OBO_SF2_PO: 272

Original comment by: cooperl09