POC Conf. Call 4-12-11

POC meeting, Webex Conference Call; Date: Tuesday April 12th, 2011 10am (PDT)

In attendance:

POC members:

Absent:

Collaborators:

Acceptance of the minutes from the POC_Conf._Call_4-5-11?

Items arising from last week's meeting:

In vitro plant structures

We agreed last week that the in vitro structures should be children of their respective plant structure parents (cell, tissue, and embryo). This required a little revision on some of the terms (see below). Also, removed part_of relationships to whole plant between plant cell and portion of plant tissue.- redundant

After much searching and discussion with developers of the other ontologies (details are available, but don't want to take up the whole meeting with them), we decided it was better to just keep "in vitro plant structure" and use a textual definition and assert dual parentage to it. This was after consultation with PATO, OBI, and GO, specifically CM.

* in vitro plant structure(PO:0000004):

Current definition: A plant structure that was derived from part of a plant and involves microbe-free growth in a sterile environment.

Proposed new def’n: A plant structure that is grown or maintained in vitro.

Comment: In vitro growth is defined as microbe-free growth in a sterile, culture environment, usually in the laboratory. An example of a sterile culture environment is growth on or in a nutrient medium in a Petri dish, culture flask or test tube. Microbes may be intentionally added to the culture environment, such as in co-culture with Agrobacterium.

• cultured protoplast(PO:0000006):

Current Def’n: In vitro isolated cells from which the entire cell wall has been enzymatically removed.

Propose renaming: plant protoplast (PO:0000006) ('cultured' is redundant here)

Proposed def’n: An in vitro plant structure that is derived from a cultured plant cell from which the entire plant cell wall has been removed.

Comment: The cell wall is generally removed using polysaccharide-degrading enzymes such as cellulase, pectinase and /or xylanase.

Note: The cultured plant cell may be in suspension culture or from callus culture on solid media

parentage: is_a in vitro plant structure, derives_from a cultured plant cell

* cultured cell (PO:0000005):

Renamed: cultured plant cell (PO:0000005)

Proposed def’n: A plant cell that is grown or maintained in vitro.

is_a plant cell, is_a in vitro plant structure

Comment: Includes isolated plant cells and small plant cell aggregates that proliferate while suspended in sterile liquid medium or spread on a solid agar medium. In cell cultures, the cells are no longer organized into tissues.

Note: in order to make this is_a plant cell, I had to revise the definition of plant cell, so that it includes cell that are not part of the whole plant.

* plant cell: (PO:0009002)

Current def’n: A cell that is part of a plant and that has as its parts a plant cell wall. [source: GO:0005623, ISBN:0471245208, POC:curators]

Comment: Applies to cells that are living or dead at maturity (e.g., fiber cell or tracheid). Definition of cell GO:0005623: "The basic structural and functional unit of all organisms. Includes the plasma membrane and any external encapsulating structures such as the cell wall and cell envelope". See definition of plant-type cell wall GO:0009505. Egg and sperm cells lack the cell wall.

Proposed new def’n: A plant structure which has as its parts a maximally connected lumen and the contents of this lumen and any external encapsulating structures (if present) such as the plasma membrane and the plant cell wall.

[source: POC:curators, GO:0005623]

Comment: Applies to cells that are living or dead at maturity (e.g., fiber cell or tracheid). Definition of cell GO:0005623: "The basic structural and functional unit of all organisms. Includes the plasma membrane and any external encapsulating structures such as the cell wall and cell envelope". See definition of plant-type cell wall GO:0009505. Egg and sperm cells lack the cell wall.

-By using 'plant structure' we cover any cells are are or were parts of a plant, plus it makes it in the g-d format.

* cultured root cell (PO:0000008): Proposed new name: root-derived cultured plant cell

current def’n: In vitro grown isolated cells and small cell aggregates that originated from isolated protoplasts after they re-established cell wall, or from callus that was induced from segment of root

Proposed new def’n: A cultured plant cell that was derived from root tissue.

Comment: The root-derived cultured plant cell may be derived from isolated protoplasts after they re-established cell wall or from callus that was induced from a segment of root.

portion of plant tissue (PO:0009007)

current definition: A plant structure that has as its parts multiple cells and is a proper part of an organ. [source: POC:curators, TAIR:lr]

Comment: These cells are organized into a structural unit, and may include an intercellular matrix.

There are several problems with this definition:

-It does not exclude cardinal organ parts.

-Saying that it is a proper part of an organ does not work for cultured callus or for tissues in plants that don't have any organs (like a protonema or thallus).

From FMA: "...consists predominantly of similarly specialized cells, with or without cells of other types and intercellular matrix"

From CARO:0000043 (also used by TAO): "Anatomical structure, that consists of similar cells and intercellular matrix, aggregated according to genetically determined spatial relationships."

Proposed definition: A plant anatomical structure that has as its parts multiple cells of the same type(s) aggregated according to genetically determined spatial relationships and is a proper part of a plant.

Comment: A portion of plant tissue may contain one or several types of cells. These cells are organized into a structural unit and may include an intercellular matrix. May include other types of isolated cells, such as idoblasts in parenchyma tissue.

Should add disjoint_from cardinal organ part.

Do we want to include the part_of whole plant relation? This would exclude cultured callus. Also, it is not consistent with our definition of plant structure which is "an anatomical structure that is or was part of a plant."

embryo (PO:0009009)

current definition: A whole plant in the post-zygotic stage that does not yet consist of fully differentiated tissues.

Comment: Adventitious embryos and somatic embryos do not arise from zygotes. Cultured embryos (PO:0000010), including haploid embryos, are in vitro plant structures. Embryos occur prior to germination in vascular plants.

This is not really consistent with the fact that we have tissues like embryonic epidermis and embryonic cortex.

Logically, an embryo could be treated like a sporophyte or gametophyte, that is, a whole plant in the embryonic life cycle phase. Since we don't have embryonic phase yet, it may be appropriate to add the embryonic phase to the PGDSO now. Also, it may be appropriate to pre-compose the term embryo, since so much research is done on embryos.

Option 1: Add embryonic phase, then define embryo as a whole plant in the embryonic phase.

Proposed definition of embryonic phase: A plant life cycle phase that is the early part of a sporophytic phase beginning with the first cell division of an organism (or could say a whole plant) and ending with emergence from the seed or archegonium.

Comment: An embryonic phase generally begins after the first division of a zygote, but in the case of adventitious embryos, somatic embryos, embryos that arise through apogamy, and cultured haploid embryos, an embryonic phase begins after the division of a single cell that is not a zygote. An embryonic phase ends with germination in the case of seed plants and with emergence from the archegonium in the case of non-seed plants (bryophytes and pteridophytes).

is_a whole plant growth phase, part_of sporophytic phase

Proposed definition of embryo: A whole plant in the embryonic phase that is contained in (located in?) an archegonium or a seed.

Comment: Haploid embryos that arise through apogamy or in vitro culture develop into haploid sporophytes.

Option 2: Do not add embryonic phase yet, and work the definition of the embryonic phase into definition of embryo.

Proposed definition of embryo: A whole plant in the early part of a sporophytic phase after the first cell division of an organism (or could say a whole plant) and before germination or emergence from the archegonium.

Comment: An embryo is generally formed after the first division of a zygote, but in the case of adventitious embryos, somatic embryos, embryos that arise through apogamy, and cultured haploid embryos, it is formed after the division of a single cell that is not a zygote. The embryonic phase ends with germination in the case of seed plants and with emergence from the archegonium in the case of non-seed plants (bryophytes and pteridophytes.

Other issues:

At the moment, haploid embryos cannot be considered in the sporophytic phase (as it it defined now), since they are not the product of fertilization. Suggest that we rework the definition of sporophytic phase with a comment about apogamy.

We could add zygotic and haploid embryo as children of embryo.

gametophytic phase and sporophytic phase

sporophytic phase (PO:0028002)

Current definition: A plant life cycle phase that is the product of fertilization. [source: POC:rw]

Comment: During the sporophtyic phase, a plant may produce meiospores by meiosis.

Proposed definition: A plant life cycle phase (or a whole plant growth stage) that begins with fertilization or the division of a non-fertilized embryogenic cell.

Comment: During the sporophtyic phase, a plant may produce meiospores by meiosis. A whole plant in the sporophytic phase usually has twice the chromosome complement of a plant in the gametophytic phase, but not in the case of apogamy or in vitro culture of haploid embryos.

gametophytic phase (PO:0028003)

Current definition: A plant life cycle phase that arises through meiosis. [source: POC:rw]

Comment: During the gametophytic phase, a plant may produce gametes by mitosis.

Proposed definition: A plant life cycle phase (or a whole plant growth stage) that begins with meiosis.

Comment: During the gametophytic phase, a plant may produce gametes by mitosis. In bryophytes and pteridophytes, a gametophytic phase may begin without meiosis, when damage to a plant in the sporophytic phase leads directly to the growth of a plant in the gametophytic phase that bears the chromosome complement that would normally be found in the sporophytic phase (apospory). A whole plant in the gametophytic phase usually has half the chromosome complement of a plant in the sporophytic phase, but not in the case of apospory.

embryonic plant structures

Definition of embryonic plant structure:

embryonic plant structure (PO:0025099): A plant structure that is part of an embryo.

Comment: Includes organs, tissues and cell types that are unique to embryos, not plant structures that can occur in both embryos and mature plant structures.

Changed definition from "proper part of" to "part of", so it would be consistent with the intersection of term. Think part_of is better anyway, because technically an embryo is an embryonic plant structure.

Some terms were left as is_a children of embryonic plant structure:

coleoptile (PO:0020033): A tubular embryonic structure developed at the junction of the cotyledonary sheath with the seedling axis, and surrounding the plumule of a monocot embryo or seedling.

embryo proper (PO:0000001): An embryonic plant structure that is the body of a developing embryo attached to the maternal tissue in an ovule by a suspensor.

scutellum (PO:0020110): An embryonic plant structure that is a more or less shield-shaped and absorptive portion of an embryo of Poaceae.

suspensor (PO:0020108): An embryonic plant structure at the base of an embryo that develops from a basal cell and connects an embryo proper to the wall of a megagametophyte.

New definitions for embryonic plant cells and tissues

Both now have cross-product definitions, and no asserted is_a children

embryonic plant cell (PO:0025028): A plant cell that is part of an embryo.

is_a embryonic plant structure, intersection_of: is_a plant cell, intersection_of: part_of embryo

Made apical cell (PO:0004000, now embryonic apical cell) is_a apical cell part_of embryo (still dev_from zygote). Should probably obsolete and replace with new term to avoid confusion

Made basal cell (PO:0002002, now embryonic basal cell) is_a plant cell, part of embryo (still dev_from zygote)

Made hypophysis (PO:0020109, now embryonic hypophysis) is_a plant cell, part_of embryo.

(portion of) embryonic plant tissue (PO:0025233): A portion of plant tissue that is part of an embryo.

is_a embryonic plant structure, intersection_of: is_a portion of plant tissue, intersection_of: part_of embryo

Should we add the portion of prefix to the name?

coleorhiza (PO:0020034), embryo cortex (PO:0005014), embryo epidermis (PO:0005015), embryonic shoot apical meristem (PO:0006362), epiblast (PO:0020036), scutellar epithelium (PO:0008048), and scutellum epidermis (PO:0006049) are now inferred children of embryonic plant tissue.

Technically, we could get rid of the is_a embryonic plant structure relation for both, because it would be inferred, but is makes it easier to work with the reasoner off when the relations are there.

Here is a picture of some plant tissues, to show how it works:

Proposed changes/questions for structures that were is_a embryonic plant structure:

embryonic leaf (PO:0006338): One of the first few leaves to develop from the embryonic shoot apical meristem [GR:pj].

Is this an embryonic plant structure, that is, is it always part of the embryo?

Proposed definition: A vascular leaf that is one of the first few leaves to develop from the embryonic shoot apical meristem and is part of an embryo.

is_a vascular leaf,

Should this really be part_of embryo? Can these leaves persist after germination?

embryonic root (PO:0000045): An embryonic plant structure that is a root that is initiated in a developing embryo. [TAIR:ki]

Propose that this should be is_a root instead of is_a embryonic plant structure, b/c it is not necessarily part of an embryo.

Proposed definition: A root that is initiated in a developing embryo.

radicle (PO:0020031): The radicle is the basal continuation of the hypocotyl in an embryo and gives rise to the root system of the adult plant; sometimes more or less abortive. is_a embryonic root [APWeb:Glossary]

Proposed definition: An embryonic root that is the basal continuation of a hypocotyl in an embryo and may develop into the root system of an adult plant.

Comment: Sometimes abortive.

remove part_of embryo axis, because it persists after germination.

hypocotyl (PO:0020100): The part of the stem below the cotyledonary node and transitional to a root, found in a young sporophyte. [APWeb:Glossary]

currently is_a cardinal organ part, propose is_a stem internode (we didn't have this term before but do now)

Proposed definition: A stem internode that is the part of a stem below the cotyledonary node and transitional to a root.

is_a stem internode

epicotyl (PO:0020035): The first internode of a stem above the hypocotyl. In literature also used for the entire embryonic axis, consisting of several internodes, above the cotyledonary node. [APWeb:Glossary]

currently is_a embryonic plant structure, propose is_a stem internode (PO:0005005). Also, the second part of the current definition only adds ambiguity. Need to define it more precisely.

Proposed definition: The first stem internode above a hypocotyl.

mesocotyl (PO:0020037): The internode between the cotyledon or cotyledons and the leaf or leaves at the next node of a young sporophyte.

This definition sounds like the same thing as an epicotyl. Should they be synonyms?

made is_a stem internode

hypocotyl-root junction PO:0004724: A cardinal organ part that is the part of an embryonic axis where the radicle joins the hypocotyl.

Moved to is_a cardinal organ part. Will automatically be is_a embryonic plant structure b/c it is part of embryonic axis. Is this accurate? The hypocotyl-root junction remains after germination.

plumule(PO:0020032): A somewhat differentiated terminal bud in several embryo types above the cotyledonary node, in which one or more internodes and leaves or scales can be discerned in a primordial stage.

made is_a terminal bud, part_of embryo

scutellar node (PO:0004708): The region in of an embryo axis between the primary root (enclosed in the coleorhiza) and the plumule (enclosed in the coleoptile) to which the scutellum is attached. [MaizeGDB:lv]

Sounds like it should be is_a stem node.

Proposed definition: A stem node that is the part of an embryo axis where the scutellum is attached.

Comment: A scutellum is attached to an embryo axis between the primary root (enclosed in the coleorhiza) and the plumule (enclosed in the coleoptile).

is_a stem node, part_of embryo axis