Sporulation Meeting Notes
August 2007 - January 2008
sporulation (sensu Bacteria)
sporulation (sensu Fungi)
spore development (sensu Magnoliophyta)
What are the distinguishing features of sporulation in different species?
Michelle speaking - I see from below the "sporulation" terms still have sensu designations - didn't we talk once about making terms that were "reproductive sporulation" and "stress-induced sporulation" or something along those lines? If so, could we carry that into these terms? I fear that there might be so much heterogeneity in spore wall structures (even within bacteria) that getting good defs based on that may be hard. But I need to do more checking.... that was just a first thought.
Eurie is to be included in one of these calls so she can get up to speed on editing techniques.
Debby Siegele (Texas A&M) (Nov 25): I think that the child terms for sporulation (GO:0030435) need to be reorganized. The current organization is shown below. A proposed reorganization is shown following my discussion of the current terms.
- GO:0030435: sporulation
- GO:0030436: sporulation (sensu Bacteria)
- GO:0042243: spore wall assembly (sensu Bacteria)
- GO:0042173: regulation of sporulation
- GO:0042244: spore wall assembly
- GO:0048622: reproductive sporulation (def: "The formation of reproductive spores." [GOC:jic])
- GO:0030437: sporulation (sensu Fungi)
- GO:0048315 : conidium formation
- GO:0031321 : prospore formation
- GO:0030476 : spore wall assembly (sensu Fungi)
- GO:0030437: sporulation (sensu Fungi)
- GO:0030436: sporulation (sensu Bacteria)
The term for sporulation (sensu Bacteria) and spore wall assembly (sensus Bacteria) should be eliminated because there are multiple types of bacterial spores (e.g. endospores, exospores, myxospores, and akinetes) and therefore multiple types of spore cell walls and assembly pathways. The term GO:0055030: peptidoglycan-based spore wall (a child term of spore wall) could be retained as it refers to a specific type of spore wall.
I would make the same argument for eliminating the term for sporulation (sensu Fungi) as different groups of fungi make spores differently. (In fact, the synonyms listed for sporulation (sensu Fungi) are specific for formation of ascospores, which excludes fungi outside the Ascomycetes.) I suspect that the terms spore wall (sensu Fungi) (GO:0005619) and spore wall assembly (sensu Fungi) should also be eliminated, since there probably isn't a common spore wall present in all fungal spores, but I don't know enough about this.
I don't know is meant by a reproductive spore. Does this refer to the spore being formed by a sexual process? or that the spores themselves are gametes (as is the case with some fern spores)? or simply that the spores will rise to a new organism? If the first is correct, then GO:0048315 shouldn't be a child term of reproductive spore, since conidia are asexual spores and the true path rule isn't followed.
I saw that one of the parent terms for reproductive sporulation is GO:0022413: reproductive process in single-celled organism. Does "single-celled" refer to spore itself? or to the organism that produces the spores?
A possible reorganization would be
- GO:0030435: sporulation
- GO:0042173: regulation of sporulation
- GO:0042244: spore wall assembly
- new GO term: formation of asexual spores
- GO:0048315: conidium formation
- new GO term: endospore formation
- new GO term: formation of sexual (meiotic) spores (or redefinition/clarification of GO:0048622: reproductive sporulation?)
- GO:0030437: redefined as ascospore formation
In AmiGO, the only genes annotated to GO:0030437: sporulation (sensu Fungi) are from S. cerevisiae and S. pombe. These are both Ascomycetes, so the change in definition wouldn't affect these annotations. Among the model organism databases, the only other organism I found with genes annotated to GO:0030437 is Dictyostelium discoidium. DictyBase has 4 genes (geneDDB0230045, geneDDB0234013, rasC, and rasD) annotated to sporulation (sensu Fungi). The annotations were inferred from electronic annotation.
Midori (Jan. 4, 2008): I have implemented the changes to fungal-type cell wall and spore wall terms as described in the notes from Nov. 2. (I have not tried to mess with the sporulation process terms, but Debby's suggestions sound reasonable. I lean toward renaming GO:0030437 and rewording its definition such that it refers to ascospore formation, because that's been the implicit meaning given who worked on it, what we were thinking of, and how it's been used.)
Feb. 14, 2008
Midori (very) rough draft of possible structure:
Please comment on this -- should any more terms be included, or anything shown be left out? I fully expect more than one round of comments before it's resolved!
[i] reproductive sporulation GO:0048622 (rename 'formation of sexual (meiotic) spores'? should we add any children, such as these:
--[i] fern-type sporulation?
--[i] moss-type sporulation?
[i] ascospore formation GO:0030437 (renamed)
--[p] ascospore wall formation GO:0030476 (renamed)
--[p] prospore formation GO:0031321 (may need to be renamed because the definition seems more specific than the name, but I haven't thought of a new name yet)
[i] (a term for basidomycete sporulation) GO:new
[i] conidium formation GO:0048315
--[p] conidium wall assembly GO:new (or "formation" instead of "assembly")
[i] endospore formation GO:new
--[p] endospore wall assembly GO:new
[i] exospore formation GO:new
--[p] exospore wall assembly GO:new
[i] myxospore formation GO:new
--[p] myxospore wall v GO:new
[i] akinete formation GO:new
--[p] akinete wall assembly GO:new
[p] spore wall assembly GO:0042244
--[i] ascospore wall formation GO:0030476 (renamed)
--[i] conidium wall assembly GO:new
--[i] endospore wall assembly GO:new
--[i] exospore wall assembly GO:new
--[i] myxospore wall v GO:new
--[i] akinete wall assembly GO:new
[p] regulation of sporulation GO:0042173
We can also add "xx spore wall" terms to the cellular component (CC) ontology.
note: we have "peptidoglycan-based spore wall" in CC (GO:0055030); does it correspond to any of the wall types listed above?
To be made obsolete:
- sporulation (sensu Bacteria) GO:0030436
- spore wall assembly (sensu Bacteria) GO:0042243
Some existing definitions should be rewritten. Two that I've had a stab at so far:
- updated earlier draft; see Definitions below
- Reproductive sporulation
- David: I don't think it was necessarily meant to be just meiotic. I think it means 'sporulation whose primary biological objective is reproduction' as opposed to 'sporulation whose primary biological objective is that of protection'. I think it was the fungal groups who worked on this part of the graph. Does it make sense that they would think of sporulation as primarily a reproductive process while you folks would think of it as a protective process? The latter distinction was entirely mine based on reading a textbook.
- Midori: David remembers more of this than I do; I would have just said I don't know where the "reproductive sporulation" term came from! We should check again with fungal experts, because in S. cerevisiae sporulation occurs in diploids in response to nutrient starvation (specifically nitrogen, if I recall correctly); it's not as obviously coupled to reproduction as in ferns or some other fungi, e.g. mushrooms. Back in my lab days I tended to think of cerevisiae sporulation as more protective than reproductive, although four spores are produced so it's got a bit of reproductive character. Sporulation in ferns and mosses would certainly fit under "reproductive sporulation"; I don't know anything more about them, such as distinguishing features or whether we would need one term or more. We should discuss whether to keep the "reproductive sporulation" term; if so, whether to change its name, what (if any) children it should have, whether to add a sibling for "sporulation in response to stress", etc.
- Pascale: I think we should use sexual and asexual to distinguish meiotic and mitotic spores. As far as I know, all spoulation is a form of reproduction. Plus there are no direct associations to 'reproductive sporulation'. This is also consistent with the definition of reproduction: 'The production by an organism of new individuals that contain some portion of their genetic material inherited from that organism.'
- Michelle: All sporulation is not reproductive. Sporulation in bacteria does not result in a net increase in the number of organisms - one cell becomes a spore and then germinates into one cell again. Sporulation in bacteria is generally a means to survive adverse conditions. So, if asexual sporulation will refer to a reproduction process, we will still need some kind of non-reproductive sporulation term.
- Jim: I think there is a problem with the fungal sporulation terms excluding or misrepresenting the basidomycetes by being marked as synonymous with ascospore processes.
- Midori: I think the apparent exclusion of basidomycetes will be addressed by renaming the existing "fungal" sporulation term and adding new terms.
- Jim: The myxospores mentioned above by Debby are made by the Myxococcales. The model organism for them is Myxococcus xanthus, and their mod is at http://xanthusbase.org. I'm trying to help them with a clade-specific cluster of MODs project right now. In an oversimplified description, myxo is sort of a bacterial version of dicty. There is social behavior followed by aggregation into a multicellular fruiting body that differentiates into spores. Some of these are quite lovely. Via googling:
February 20, 2008 Skype "meeting"
Present: Midori, Debby, Maria, Pascale, Val
We discussed whether sporulation should go under reproduction; it's not resolved yet, but the other changes don't depend on the decision. If sporulation (GO:0030435) itself doesn't go under reproduction, descendants of sporulation can have reproduction as an additional parent as needed.
Changes we did decide on:
- Create two child terms, for spores produced by mitosis (= asexual) and by meiosis (sexual), The definitions probably need work; any other comments also welcome. Definitions below.
- For types of sporulation observed in bacteria, Debby will look up distinguishing features that can be used in definitions; Midori will help convert that information into GO-definition-friendly sentences. See below ...
- Rename 30437 to ascospore formation, and improve definition; also rename 30476 to ascospore wall assembly.
- Move conidium formation (GO:0048315) to is_a mitotic/asexual sporulation.
- We agreed to make three terms obsolete:
- reproductive sporulation GO:0048622
- This term is ill defined, so much so that we don't know what it was intended to mean; it also has a parent (reproductive process in single-celled organism) that isn't consistent with the 'sporulation whose primary biological objective is reproduction' meaning (true path violation - cf ferns, mosses, mushrooms). No gene products are annotated directly to GO:0048622
- sporulation (sensu Bacteria) GO:0030436
- This is a grouping term that isn't useful -- there are several different types of spore formed by different species/genera/etc. of bacteria, and there is neither a need nor a good basis for grouping them with each other.
- spore wall assembly (sensu Bacteria) GO:0042243
- Reasons analogous to those given for GO:0030436 above.
- Sexual or meiotic spores (child term of sporulation)
- Ascospores (meiotically produced spores form by Ascomycetes)
- Basidiospores (is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. From Wikipedia)
- Zygospores (Zygomycota, or zygote fungi, are a phylum of fungi. The name of the phylum comes from zygosporangia, where resistant spherical spores are formed during sexual reproduction. From Wikipedia)
- Asexual or mitotic spores (child term of sporulation)
- Arthrospores (aka oidia)(Hypha fragment through splitting of the cell wall to form cells that behave as spores. Prescott ) (asexual spores formed by Basidiomycetes)
- Blastospores (Spores produced from a vegetative mother cell by budding. Prescott) (produced by Candida, produced by fungi in the class Glomeromycota, others?)
- Chlamydospores (Spores produced by hyphal fragmentation that are surrounded by a thick wall before separation. Prescott)
- Conidia (Spores produced at the tips or sides of a hyphae, but are not enclosed in a sac. Prescott) (asexual spores formed by Ascomycetes)
- Sporangiospores (Asexual Spores that develop with a sac (sporangia) at a hyphal tip. Prescott) (A spore that is formed by a cleavage process following karyogamy and mitosis in a sporangium. Dr. Fungus) (produced by fungi in the class Chytridiomycota, differ from conidia in being surrounded by a second wall) Sporangium (pl. sporangia): An asexual sac-like cell that has its entire content cleaved into sporangiospores.
- Dictyostelium - forms spores inside fruiting bodies
- Endospore (Dormant, highly resistant spore with a thick wall that forms within another cell, produced by some low G+C Gram-positive bacteria)
- Akinete (An akinete is a thick-walled dormant cell derived from the enlargement of a vegetative cell. It serves as a survival structure. It is a resting cell of cyanobacteria and unicellular and filamentous green algae.  Under magnification, akinetes appear thick walled with granular-looking cytoplasms.)
- Actinomycetes (High G+C Gram-positive bacteria that form spores)
Midori: Current draft of the proposed ontology structure (Feb. 20):
[i] asexual sporulation GO:new
--[i] conidium formation GO:0048315
--[new terms as needed, e.g. as in Feb. 14 draft above]
[i] sexual sporulation GO:new --[i] ascospore formation GO:0030437 (renamed)
-- --[p] ascospore wall formation GO:0030476 (renamed)
-- --[p] ascospore-type prospore formation GO:0031321 (renamed; suggestions welcome for nicer new name)
--[other new terms as needed, e.g. as in Feb. 14 draft above]
--[p] spore wall assembly GO:0042244
-- --[i] ascospore wall formation GO:0030476 (renamed)
-- --[other new terms as needed, e.g. as in Feb. 14 draft above]
(Feb. 26; Midori) (minor updates March 7; Midori)
id: GO:0030435 name: sporulation def: "The process by which a relatively unspecialized cell acquires the specialized features of a spore, a cell form that can be used for dissemination, for survival of adverse conditions because of its heat and dessication resistance, and/or for reproduction.Spores are usually unicellular and may develop into vegetative organisms or gametes. They may be produced asexually or sexually and are of many types." [GOC:mah; ISBN:0072992913] id: GO:0030436 name: asexual sporulation def: "The formation of spores derived from the products of mitosis." [GOC:mah; PMID: 9529886] synonym: "asexual spore formation" EXACT  synonym: "mitotic sporulation" EXACT  synonym: "mitotic spore formation" EXACT  synonym: "spore formation (sensu Bacteria)" NARROW  synonym: "sporulation (sensu Bacteria)" NARROW  is_a: GO:0030435 ! sporulation id: GO:new name: sexual sporulation def: "The formation of spores derived from the products of meiosis." [GOC:mah] synonym: "meiotic sporulation" EXACT  synonym: "meiotic spore formation" EXACT  synonym: "sexual spore formation" EXACT  is_a: GO:0030435 ! sporulation Note: any of the synonyms could be used as the term name, if you prefer. id: GO:0030437 name: ascospore formation def: "The process by which a diploid cell undergoes meiosis, and the meiotic products acquire the specialized features of ascospores. Ascospores are generally found in clusters of four or eight spores within a single mother cell, the ascus, and are characteristic of the ascomycete fungi (phylum Ascomycota)." [GOC:mah; PMID:16339736] is_a: GO:new ! sexual sporulation id: GO:new name: basidiospore formation def: "The process by which spores form outside a specialized end cell known as a basidium. Basidia are characteristic of the basidiomycete fungi (phylum Basidiomycota), and give rise to spores that each contain a haploid nucleus that is the product of meiosis. The spores are usually attached to the basidium by short spikes called sterigmata (singular: sterigma). In most basidiomycetes there are four sterigmata (and four spores) to a basidium." [GOC:mah, GOC:ds, http://www.ilmyco.gen.chicago.il.us/Terms/basid133.html, http://www.gsbs.utmb.edu/microbook/ch073.htm] is_a: GO:new ! sexual sporulation id: GO:new name: zygospore formation def: "The process by which zygospores are formed. Zygospores are characteristic of the zygomycete fungi (phylum Zygomycota) thick-walled and darkly colored, and usually heavily ornamented as well, with many spines or ridges. It is formed between two specialized organs called suspensors, which are themselves usually heavily ornamented, one from each mating partner. The zygospore forms between them and then breaks away." [GOC:mah, GOC:ds, http://www.ilmyco.gen.chicago.il.us/Terms/zygos581.html] is_a: GO:new ! sexual sporulation
more Feb. 28 (Midori)
I think some of these are likely to require more work, because different sources don't quite agree on some things, especially for "chlamydospore" -- the Illinois Mycological Association fungal term glossary says that chlamydospores can be sexual or asexual. I'm also not sure where the part about hyphal fragmentation that Debby found in Prescott belongs. And we also have to deal with the existing term 'chlamydospore developmen GO:0001410, which is defined and used for structures in Candida that may not be true spores.
I've concocted two possible versions, with one or two chlamydospore formation terms (note that neither option considers the GO:0001410 wrinkle).
refs: PMID: 16215181, http://www.ilmyco.gen.chicago.il.us/Terms/chlam385.html, the wiki and sources noted therein
One possibility: id: GO:new name: chlamydospore formation def: "The process by which chlamydospores, a specialized type of spore found in fungi, are formed. Chlamydospores are larger than the standard spores produced by the fungus, have a very thick wall, and are usually darkly pigmented." [GOC:mah, http://www.ilmyco.gen.chicago.il.us/Terms/chlam385.html] is_a: GO:0030435 ! sporulation id: GO:new name: asexual chlamydospore formation def: "The process by which chlamydospores, a specialized type of spore found in fungi, are formed from products of mitosis. Chlamydospores are larger than the standard spores produced by the fungus, have a very thick wall, and are usually darkly pigmented." [GOC:mah, http://www.ilmyco.gen.chicago.il.us/Terms/chlam385.html] synonym: "chlamyodoconidium formation" EXACT [http://en.wikipedia.org/wiki/Chlamydospore] is_a: GO:0048315 ! conidium formation Another possibility, assuming that all chlamydospores are formed asexually after all: id: GO:new name: chlamydospore formation def: "The process by which chlamydospores, a specialized type of spore found in fungi, are formed. Chlamydospores are produced by hyphal fragmentation and are surrounded by a thick wall before separation." [GOC:mah, GOC:ds, ISBN:??] is_a: GO:0030435 ! sporulation
more defs that I'm reasonably confident of:
id: GO:0048315 name: conidium formation def: "The process by which conidia, nonmotile asexual spores found in fungi, are formed. Conidia form on specialized structures called conidiophores, which may arise by conversion of hyphal elements or from specialized sporogenous cells." [ISBN:0963117211, PMID:2524423, PMID:9529886, http://www.ilmyco.gen.chicago.il.us/Terms/conid162.html] id: GO:new name: oidium formation def: "The process by which oidia, a type of asexual spore found in fungi, are formed. Oidia are borne a few at a time on very simple hyphae that protrude a short distance into the substrate, and are usually presumed not to constitute the main reproductive strategy of the fungus." [GOC:mah, http://www.ilmyco.gen.chicago.il.us/Terms/oidiu163.html] is_a: GO:0030436 ! asexual sporulation id: GO:new name: arthrospore formation def: "The formation of conidia by the conversion of a pre-existing hypha. An arthrospore is produced by the last cell on a hypha breaking off and dispersing. Usually the walls thicken and the cell(s) separates before swelling of each spore. Sometimes further septa form in each cell prior to disarticulation." [GOC:mah, http://www.ilmyco.gen.chicago.il.us/Terms/arthr620.html, http://bugs.bio.usyd.edu.au/Mycology/Glossary/glossary_a_b.shtml#arthrospore] synonym: "arthroconidium formation" EXACT [http://medical.merriam-webster.com/medical/medical?book=Medical&va=arthroconidium] is_a: GO:0048315 ! conidium formation Note: I also noticed some older papers (e.g. PMID: 618842) that use "arthrospore" to refer to a type of bacterial spore. Do we need to worry about that? id: GO:new name: blastospore formation def: "The formation of produced from a vegetative mother cell by budding. Blastospores are a type of asexual spore found in some fungi, including Candida species and the class Glomeromycota." [GOC:ds, ISBN:??] synonym: "blastoconidium formation" EXACT [http://cancerweb.ncl.ac.uk/cgi-bin/omd?Blastoconidium] is_a: GO:0048315 ! conidium formation id: GO:new name: sporangiospore formation def: "The process by which sporangiospores, a type of asexual spore found in fungi, are formed. Sporangiospores are formed within sac-like structure, the sporangium, following the division of the cytoplasm" [GOC:mah, GO:ds, http://bugs.bio.usyd.edu.au/Mycology/Glossary/glossary_n_z.shtml] is_a: GO:0030436 ! asexual sporulation id: GO:new name: endospore formation def: "The process by which a cell gives rise to an endospore, a dormant, highly resistant spore with a thick wall that forms within the mother cell. Endospores are produced by some low G+C Gram-positive bacteria in response to harsh conditions." [GOC:mah, GOC:ds, http://howie.myweb.uga.edu/introduction.html] is_a: GO:0030436 ! asexual sporulation id: GO:new name: akinete formation def: "The process by which an akinete, a thick-walled (encysted) dormant cell derived from the enlargement of a vegetative cell, is formed ''in several groups of Cyanobacteria''. Akinetes typically have granular cytoplasm." ''Akinetes are more resistant to environmental extremes than vegetative cells.'' [GOC:mah, GOC:ds, PMID:11948167, http://www.msu.edu/course/bot/423/algalglossary.htm#Reproductive] another def: is_a: GO:0030436 ! asexual sporulation id: GO:new name: myxospore formation def: The process by which differentiated, resting cells are formed usually within a fruiting body by Myxobacteria, usually within a fruiting body. The myxospore is more resistant to high temperature, dessication, and UV than vegetative myxobacteria. (encyclopedia of microbiology) is_a: GO:0030436 ! asexual sporulation id: GO:new name: actinomycete-type spore formation? another def: Formation of differentiated, resting celsls from a substrate mycelium in many members of the order Actinomycetales. def: ?? might be able to use http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=70 but need distinguishing features of the spores is_a: GO:0030436 ! asexual sporulation id: GO:0042243 (or GO:new) name: asexual spore wall formation def: "The chemical reactions and pathways resulting in the formation of the specialized envelope lying outside the cell membrane of a spore derived from a product of mitosis." [GOC:mah] (or 'spore wall formation, asexual', 'formation of asexual spore wall'?) id: GO:new name: sexual spore wall formation def: "The chemical reactions and pathways resulting in the formation of the specialized envelope lying outside the cell membrane of a spore derived from a product of meiosis." [GOC:mah] name changes only: id: GO:0030476 name: ascospore wall assembly id: GO:0034217 name: ascospore wall chitin biosynthetic process id: GO:0034218 name: ascospore wall chitin metabolic process id: GO:0034232 name: ascospore wall chitin catabolic process id: GO:0034223 name: regulation of ascospore wall chitin biosynthetic process id: GO:0034234 name: regulation of ascospore wall chitin catabolic process id: GO:0042763 name: intracellular immature spore id: GO:0042764 name: ascospore-type prospore?? check annotations
March 7, 2008
By email and at the last meeting (March 4th), we agreed to use GO:0030436 as the 'asexual sporulation' term rather than make it obsolete; ditto for GO:0042243 and spore walls. I've made other changes as agreed -- the parent 'sporulation' term is not under reproduction, but some of its children have additional parentage leading to reproduction, and additional relationships can be made if we've missed any sporulation types that should have paths to reproduction.
I have not added any new 'chlamydospore' terms, but can do so once we've sorted out the existing 'chlamydospore development' term and whether we need another term for chlamydospores that are unambiguously regarded as spores.
I also haven't added any new *spore wall assembly terms except GO:0034294, but can add terms as the need arises.
new terms sexual sporulation GO:0034293 sexual spore wall assembly GO:0034294 basidiospore formation GO:0034295 zygospore formation GO:0034296 oidium formation GO:0034297 arthrospore formation GO:0034298 blastospore formation GO:0034299 sporangiospore formation GO:0034300 endospore formation GO:0034301 akinete formation GO:0034302 myxospore formation GO:0034303 actinomycete-type spore formation GO:0034304 regulation of asexual sporulation GO:0034305 regulation of sexual sporulation GO:0034306 regulation of ascospore formation GO:0034307 terms moved ascospore formation GO:0030437 to is_a GO:0034293 conidium formation GO:0048315 to is_a GO:0030436
March 18, 2008 Chlamydospores
Based on the reading I've done chlamydospores are a mitotic spore formed by many different types of filamentous fungi. The 9th edition of Ainsworth & Bisby’s Dictionary of the Fungi (2001,ISBN:085199377X) gives the following definition for chlamydospore: "an asexual 1-celled spore (primarily for perennation, not dissemination) originating endogenously and singly within part of a pre-existing cell, by the contraction of the protoplast and possessing an inner seconary and often thickened hyaline or brown wall, usually impregnated with hydrophobic material. Originally proposed by de Bary in 1859 for Asterophora anamorphs. See Griffiths (Nova Hedw. 25: 503, 1974; origin, structure, function), Hughes (in Arai (Ed.), Filamentous microorganisms: 1, 1985; definition, occurrence)."
I suggest that GO term 'GO:0001410 chlamydospore development' be redefined so that it is inclusive of all fungal groups rather than being written specifically for Candida sp. and also that it be included under the parent term 'GO:0030435: sporulation'. The new definition could be based on the definition from Ainsworth & Bisby as follows: "a mitotic (asexual) 1-celled spore (primarily for survival, not dispersal) originating endogenously and singly within part of a pre-existing cell and possessing an inner secondary and often thickened cell wall." I've copied the current definition for term GO:0001410 below for comparison.
id: GO:0001410 name: chlamydospore development namespace: biological_process alt_id: GO:0055027 def: "The process whose specific outcome is the progression of the chlamydospore over time, from its formation to the mature structure. Chlamydospores are thick-walled, spore-like cells borne on the ends of elongated cells attached to hyphae or pseudohyphae, seen in the species Candida albicans and Candida dubliniensis. Note that although these structures resemble the chlamydospores of other fungi, it is not known whether they are true spores, so this process is not currently considered an instance of spore formation." [GOC:mcc, GOC:mtg_sensu, PMID:14663094]
(Maria) I've just returned from a Candida meeting, and the exact nature of Candida chlamydospores is not understood. However, they do seem to be resting cells, and they can be isolated and germinated. The suggested definition above sounds like it would be appropriate.