Wikipedia

Stramenopile

(Redirected fromHeterokonta)

TheStramenopiles,also calledHeterokonts,are acladeof organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached toflagella,in some they are attached to other areas of the cellular surface, and in some they have been secondarily lost (in which case relatedness to stramenopile ancestors is evident from other shared cytological features or from genetic similarity). Stramenopiles represent one of the three major clades in theSAR supergroup,along withAlveolataandRhizaria.

Stramenopiles
Temporal range: LateMesoproterozoic-present,1025–0 Ma[1]
KelpOomyceteBicosoecidDiatomLabyrinthulomycetesOpalineYellow-green algaeGolden algaeSilicoflagellate
Diversity of stramenopiles
Scientific classificationEdit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Patterson 1989[2]emend. Adl et al. 2005[3]
Phyla and subphyla[4]
Diversity
>100000 species[1]
Synonyms

Stramenopiles areeukaryotes;most are single-celled, but some are multicellular including some large seaweeds, thebrown algae.The group includes a variety of algalprotists,heterotrophic flagellates,opalinesand closely relatedproteromonadflagellates (allendobiontsin other organisms); the actinophryidheliozoa,andoomycetes.The tripartite hairs characteristic of the group have been lost in some of the included taxa – for example in mostdiatoms.

Many stramenopiles are unicellularflagellates,and most others produce flagellated cells at some point in their lifecycles, for instance asgametesorzoospores.Most flagellated heterokonts have two flagella; the anterior flagellum has one or two rows of stiff hairs ormastigonemes,and the posterior flagellum is without such embellishments, being smooth, usually shorter, or in a few cases not projecting from the cell.

The term 'heterokont' is used both as an adjective – indicating that a cell has two dissimilar flagella, and as the name of a taxon. The groups included in that taxon have however varied widely, creating the 'heterokont problem', now resolved by the definition of the stramenopiles.

History

edit

The term 'stramenopile' was introduced byD. J. Pattersonin 1989, defining a group that overlapped with the ambiguously definedheterokonts.[12][13]The name "stramenopile" has been discussed by J. C. David.[14]

The heterokont problem

edit

The term 'heterokont' is used as both an adjective – indicating that a cell has two dissimilar flagella – and as the name of a taxon. The taxon 'Heterokontae' was introduced in 1899 by Alexander Luther for algae that are now considered theXanthophyceae.[15]But the same term was used for other groupings of algae. For example, in 1956, Copeland[16]used it to include the xanthophytes (using the name Vaucheriacea), a group that included what became known as thechrysophytes,thesilicoflagellates,and thehyphochytrids.Copeland also included the unrelated collar flagellates (as thechoanoflagellates) in which he placed thebicosoecids.He also included the not-closely relatedhaptophytes.The consequence of associating multiple concepts to the taxon 'heterokont' is that the meaning of 'heterokont' can only be made clear by making reference to its usage: Heterokontae sensu Luther 1899; Heterokontae sensu Copeland 1956, etc. This contextual clarification is rare, such that when the taxon name is used, it is unclear how it should be understood. The term 'Heterokont' has lost its usefulness in critical discussions about the identity, nature, character and relatedness of the group.[17]The term 'stramenopile' sought to identify a clade (monophyletic and holophyletic lineage) using the approach developed by transformed cladists of pointing to a defining innovative characteristic or apomorphy.[18]

Over time, the scope of application has changed, especially when in the 1970s ultrastructural studies revealed greater diversity among the algae with chromoplasts (chlorophylls a and c) than had previously been recognized. At the same time, a protistological perspective was replacing the 19th century one based on the division of unicellular eukaryotes into animals and plants. One consequence was that an array of heterotrophic organisms, many not previously considered as 'heterokonts', were seen as related to the 'core heterokonts' (those having anterior flagella with stiff hairs). Newly recognized relatives included the parasiticopalines,proteromonads,and actinophryidheliozoa.They joined other heterotrophic protists, such asbicosoecids,labyrinthulids,andoomycetefungi, that were included by some as heterokonts and excluded by others. Rather than continue to use a name whose meaning had changed over time and was hence ambiguous, the name 'stramenopile' was introduced to refer to the clade of protists that had tripartite stiff (usually flagellar) hairs and all their descendants. Molecular studies confirm that the genes that code for the proteins of these hairs are exclusive to stramenopiles.[19]

Characteristics

edit
Schematic drawing ofCafeteria roenbergensis(a heterotrophicbicosoecid), a common bacterivore in marine ecosystems: the anterior flagellum is tripartite and covered with hairs (mastigonemes); the posterior flagellum is without hairs.
Two livingC. roenbergensis.Light micrograph. The cells are about 6 µm long. The anterior flagellum beats with an undulating pattern, the posterior (recurrent or smooth) flagellum usually holds the cell to the substrate.

The presumedapomorphyof tripartite flagellar hairs in stramenopiles is well characterized. The basal part of the hair is flexible and inserts into the cell membrane; the second part is dominated by a long stiff tube (the 'straw' or 'stramen'); and finally the tube is tipped by many delicate hairs calledmastigonemes.[20]The proteins that code for the mastigonemes appear to be exclusive to the stramenopile clade, and are present even in taxa (such as diatoms) that no longer have such hairs.[21]

Most stramenopiles have two flagella near the apex.[22]They are usually supported by fourmicrotubuleroots in a distinctive pattern. There is a transitional helix inside the flagellum where the beatingaxonemewith its distinctive geometric pattern of nine peripheral couplets around two central microtubules changes into the nine-triplet structure of the basal body.[23]

Plastids

edit

Many stramenopiles haveplastidswhich enable them tophotosynthesise,using light tomake their own food.Those plastids are coloured off-green, orange, golden or brown because of the presence ofchlorophyll a,chlorophyll c,andfucoxanthin.This form of plastid is called a stramenochrome orchromoplast.[a]The most significant autotrophic stramenopiles are thebrown algae(wracks and many other seaweeds), and thediatoms.The latter are among the most significant primary producers in marine and freshwater ecosystems.[24]Most molecular analyses suggest that the most basal stramenopiles lacked plastids and were accordingly colourlessheterotrophs,feeding on other organisms. This implies that the stramenopiles arose as heterotrophs, diversified, and then some of them acquired chromoplasts. Some lineages (such as theaxodinelineage that included the chromophyticpedinellids,colourless ciliophryids, and colourless actinophryid heliozoa) have secondarily reverted to heterotrophy.[25][26]

Ecology

edit
Giant kelp,Macrocystis pyrifera,an example of a multicellular stramenopile, is a largeseaweed,up to 45 metres (150 feet) long, in thePhaeophyceae,within the Gyrista.

Some stramenopiles are significant as autotrophs and as heterotrophs in natural ecosystems; others are parasitic. Blastocystisis a gastrointestinal parasite of humans;[27] opalines and proteromonads live in the intestines of cold-blooded vertebrates and have been described as parasitic;[28] oomycetes include some significant plant pathogens such as the cause of potato blight,Phytophthora infestans.[29] Diatoms are major contributors to global carbon cycles because they are the most important autotrophs in most marine habitats.[30] The brown algae, including familiar seaweeds like wrack and kelp, are major autotrophs of the intertidal and subtidal marine habitats.[31] Some of the bacterivorous stramenopiles, such asCafeteria,are common and widespread consumers of bacteria, and thus play a major role in recycling carbon and nutrients withinmicrobial food webs.[32][33]

Evolution

edit

External

edit

Stramenopiles are most closely related to Alveolates and Rhizaria, all of which have tubular mitochondrialcristaeand collectively form theSAR supergroup,whose name is formed from their initials.[34][26][35]The ancestor of the SAR supergroup appears to have captured a unicellular photosyntheticred alga,and many Stramenopiles, as well as members of other SAR groups such as the Rhizaria, still have plastids which retain the double membrane of the red alga and a double membrane surrounding it, for a total of four membranes.[36]In addition, species ofTelonemia,the sister group to SAR, exhibit heterokont flagella with tripartite mastigonemes, implying a more ancient origin of stramenopile characteristics.[37]

TSAR

Internal

edit

The followingcladogramsummarizes the evolutionary relationships between Stramenopiles. Thephylogeneticrelationships ofBigyravary greatly from one analysis to the next: it has been recovered as eithermonophyletic[38][39]orparaphyletic.When paraphyletic, the branching order of the bigyran groups also varies: in some studiesSagenistais the most basal-branching clade,[38][40][41]while in othersOpalozoais the most basal.[42]Nonetheless,Platysulceais consistently recovered as thesister cladeto all other stramenopiles.[39][40]In addition, a flagellate species discovered in 2023,Kaonashia insperata,remains in an uncertain phylogenetic position, but more closely related toGyristathan to other clades.[41]

Stramenopiles

Classification

edit
Electron micrograph of the protistParaphysomonas butcheri.It illustrates the stramenopile property – of having stiff hairs. The hairs attach to one longer flagellum, the other is without hairs (an arrangement also called 'heterokont', meaning "unequal" ). The body of the flagellate is coated with delicate scales.Paraphysomonasfeeds on bacteria, two of which lie near the hairy flagellum.

The classification of the Stramenopiles according to Adlet al.(2019), with additions from newer research:[43] [4]

Notes

edit
  1. ^They are not called chloroplasts, the most common form of photosynthetic plastid. If used narrowly, a chloroplast is a plastid which contains chlorophyll B, as ingreen algae,someeuglenids,and theland plants.

References

edit
  1. ^abH.S. Yoon; R.A. Andersen; S.M. Boo; D. Bhattacharya (17 February 2009)."Stramnenopiles".Encyclopedia of Microbiology (Third Edition):721–731.doi:10.1016/B978-012373944-5.00253-4.Retrieved2 March2024.
  2. ^Patterson, D.J. (1989). "Stramenopiles: Chromophytes from a protistan perspective". In Green, J.C.; Leadbeater, B.S.C.; Diver, W.L. (eds.).The chromophyte algae: Problems and perspectives.Clarendon Press.ISBN978-0198577133.
  3. ^Sina M Adl; Alastair G B Simpson; Mark A Farmer; et al. (1 September 2005). "The new higher level classification of eukaryotes with emphasis on the taxonomy of protists".Journal of Eukaryotic Microbiology.52(5): 399–451.doi:10.1111/J.1550-7408.2005.00053.X.ISSN1066-5234.PMID16248873.WikidataQ22065654.
  4. ^abCavalier-Smith, Thomas (January 2018)."Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences".Protoplasma.255(1): 297–357.doi:10.1007/s00709-017-1147-3.PMC5756292.PMID28875267.
  5. ^Vørs, N. (1993). "Marine heterotrophic amoebae, flagellates and heliozoa from Belize (Central America) and Tenerife".Journal of Eukaryotic Microbiology.40(3): 272–287.doi:10.1111/j.1550-7408.1993.tb04917.x.S2CID221852241.
  6. ^David, J.C. (2002)."A preliminary catalogue of the names of fungi above the rank of order".Constancea.83:1–30.
  7. ^Cavalier-Smith, T.(1999)."The kingdom Chromista, origin and systematics".In Round, F.E.; Chapman, D.J. (eds.).Progress in Phycological Research.Vol. 4. Elsevier. pp. 309–347.ISBN978-0-948737-00-8.
  8. ^van den Hoek, C.; Mann, D.G.; Jahns, H.M. (1995).Algae An Introduction to Phycology.Cambridge University Press.ISBN978-0-521-30419-1.
  9. ^Alexopoulos, C.J.; Mims, C.W.; Blackwell, M. (1996).Introductory Mycology(4th ed.). Wiley.ISBN978-0471522294.
  10. ^Dick, M.W. (2013).Straminipilous Fungi: Systematics of the Peronosporomycetes Including Accounts of the Marine Straminipilous Protists, the Plasmodiophorids and Similar Organisms.Springer.ISBN978-94-015-9733-3.
  11. ^"Stramenipila M.W. Dick (2001)".MycoBank.International Mycological Association.
  12. ^Patterson, D. J. (1989). "Stramenopiles: chromophytes from a protistological perspective". In Green, J. C.; Leadbeater, B. S. C.; Diver, W. L. (eds.).The chromophyte algae: problems and perspectives.Oxford: Clarendon Press. pp. 357–379.
  13. ^Patterson, David J. (1999). "The Diversity of Eukaryotes".The American Naturalist.154(S4): S96–S124.doi:10.1086/303287.PMID10527921.S2CID4367158.
  14. ^David, J. C. (2002)."A preliminary catalogue of the names of fungi above the rank of order".Constancea(83): 1–30.
  15. ^Luther, Alexander F. (1899).Über Chlorosaccus eine neue Gattung der Süsswasseralgen nebst einiger Bemerkungen zur Systematik verwandter Algen[About Chlorosaccus a new genus of freshwater algae together with some comments on the systematics of related algae] (in German). Stockholm:Norstedt.pp. 1–22.
  16. ^Copeland, H. F. (1956).The Classification of Lower Organisms.Palo Alto, California: Pacific Books.
  17. ^Blackwell, W. H. (2009)."Chromista revisited: A dilemma of overlapping putative kingdoms, and the attempted application of the botanical code of nomenclature"(PDF).Phytologia.91(2).
  18. ^Patterson, Colin (1982). "Morphological characters and homology". In Joysey, Kenneth A.; Friday, A. E. (eds.).Problems in Phylogenetic Reconstruction.Systematics Association Special Volume 21. London: Academic Press.ISBN978-0-1239-1250-3.
  19. ^Hee, Wei Yih; Blackman, Leila M.; Hardham, Adrienne R. (2019). "Characterisation of Stramenopile-specific mastigoneme proteins in Phytophthora parasitica".Protoplasma.256(2): 521–535.doi:10.1007/s00709-018-1314-1.PMID30302550.S2CID52947780.
  20. ^Bouck, G. Benjamin (1 August 1971)."The structure, origin, and composition of the tubular mastigonemes of theOchromonasflagellum ".Journal of Cell Biology.50(2): 362–384.doi:10.1083/jcb.50.2.362.PMC2108286.PMID5123323.
  21. ^Blackman, Leila M.; Arikawa, Mikihiko; Yamada, Shuhei; Suzaki, Toshinobu; Hardham, Adrienne R. (2011). "Identification of a Mastigoneme Protein from Phytophthora nicotianae".Protist.162(1): 100–114.doi:10.1016/j.protis.2010.01.005.PMID20663714.
  22. ^Yoon, H.S.; Andersen, R.A.; Boo, S.M.; Bhattacharya, D. (2009). "Stramenopiles".Encyclopedia of Microbiology.Elsevier. pp. 721–731.doi:10.1016/b978-012373944-5.00253-4.ISBN9780123739445.
  23. ^Fu, Gang; Nagasato, Chikako; Oka, Seiko; Cock, J. Mark; Motomura, Taizo (2014)."Proteomics Analysis of Heterogeneous Flagella in Brown Algae (Stramenopiles)"(PDF).Protist.165(5): 662–675.doi:10.1016/j.protis.2014.07.007.PMID25150613.S2CID7936118.
  24. ^Leipe, D. D.; Wainright, P. O.; Gunderson, J. H.; et al. (1994). "The stramenopiles from a molecular perspective: 16S-like rRNA sequences from Labyrinthuloides minuta and Cafeteria roenbergensis".Phycologia.33(5): 369–377.doi:10.2216/i0031-8884-33-5-369.1.
  25. ^Leyland, Ben; Leu, Stefan; Boussiba, Sammy (2017). "Are Thraustochytrids algae?".Fungal Biology.121(10): 835–840.doi:10.1016/j.funbio.2017.07.006.PMID28889907.
  26. ^abDerelle, Romain; López-García, Purificación; Timpano, Hélène; Moreira, David (10 August 2016)."A Phylogenomic Framework to Study the Diversity and Evolution of Stramenopiles (=Heterokonts)".Molecular Biology and Evolution.33(11): 2890–2898.doi:10.1093/molbev/msw168.PMC5482393.PMID27512113.
  27. ^Roberts, Tamalee; Stark, Damien; Harkness, John; Ellis, John (2014)."Update on the pathogenic potential and treatment options for Blastocystis sp".Gut Pathogens.6(1): 17.doi:10.1186/1757-4749-6-17.PMC4039988.PMID24883113.
  28. ^Olsen, O. Wilford (1986).Animal Parasites: their life cycles and ecology.New York: Dover. pp. 56, 74–75.ISBN0-486-65126-6.OCLC13123309.
  29. ^Nowicki, Marcin; et al. (17 August 2011)."Potato and tomato late blight caused byPhytophthora infestans:An overview of pathology and resistance breeding ".Plant Disease.96(1).American Phytopathological Society:4–17.doi:10.1094/PDIS-05-11-0458.PMID30731850.
  30. ^Yool, Andrew; Tyrrell, Toby (2003). "Role of diatoms in regulating the ocean's silicon cycle".Global Biogeochemical Cycles.17(4): n/a.Bibcode:2003GBioC..17.1103Y.CiteSeerX10.1.1.394.3912.doi:10.1029/2002GB002018.S2CID16849373.
  31. ^Cock, J. Mark; Peters, Akira F.; Coelho, Susana M. (2011-08-09)."Brown algae".Current Biology.21(15): R573–R575.doi:10.1016/j.cub.2011.05.006.PMID21820616.
  32. ^Guiry, Wendy (7 April 2011)."Cafeteria T.Fenchel & D.J.Patterson 1988".AlgaeBase.Retrieved17 March2023.
  33. ^Fenchel, T.; Patterson, D. J. (1988)."Cafeteria roenbergensisnov. gen., nov. sp., a heterotrophic microflagellate from marine plankton ".Marine Microbial Food Webs.3:9–19.
  34. ^Krylov, M. V.; Dobrovolskii, A. A.; Issi, I. V.; Michaelevich, B. I.; Podlipaev, S. A.; Reshetnyak, V. V.; Seravin, L. N.; et al. 1980. New concepts for the system of unicellular organisms. Trudy Zoologischkei Institut Akademiya Nayuk, SSSR 94:122–132.
  35. ^Burki, F.; Shalchian-Tabrizi; Pawlowski, J. (August 2008)."Phylogenomics reveals a new 'megagroup' including most photosynthetic eukaryotes".Biology Letters.4(4): 366–369.doi:10.1098/rsbl.2008.0224.PMC2610160.PMID18522922.
  36. ^Oborník, Miroslav; Lukeš, Julius (2013). "Cell Biology of Chromerids".International Review of Cell and Molecular Biology.Vol. 306.Elsevier.pp. 333–369.doi:10.1016/b978-0-12-407694-5.00008-0.ISBN9780124076945.PMID24016529.
  37. ^Tikhonenkov, Denis V.; Jamy, Mahwash; Borodina, Anastasia S.; Belyaev, Artem O.; Zagumyonnyi, Dmitry G.; Prokina, Kristina I.; Mylnikov, Alexander P.; Burki, Fabien; Karpov, Sergey A. (2022)."On the origin of TSAR: morphology, diversity and phylogeny of Telonemia".Open Biology.12(3). The Royal Society.doi:10.1098/rsob.210325.ISSN2046-2441.PMC8924772.PMID35291881.
  38. ^abCavalier-Smith, Thomas; Scoble, Josephine Margaret (2013). "Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes".European Journal of Protistology.49(3): 328–353.doi:10.1016/j.ejop.2012.09.002.PMID23219323.
  39. ^abcThakur, Rabindra; Shiratori, Takashi; Ishida, Ken-ichiro (2019)."Taxon-rich Multigene Phylogenetic Analyses Resolve the Phylogenetic Relationship Among Deep-branching Stramenopiles".Protist.170(5): 125682.doi:10.1016/j.protis.2019.125682.ISSN1434-4610.PMID31568885.S2CID202865459.
  40. ^abcShiratori, Takashi; Thakur, Rabindra; Ishida, Ken-ichiro (2017)."Pseudophyllomitus vesiculosus (Larsen and Patterson 1990) Lee, 2002, a Poorly Studied Phagotrophic Biflagellate is the First Characterized Member of Stramenopile Environmental Clade MAST-6".Protist.168(4): 439–451.doi:10.1016/j.protis.2017.06.004.ISSN1434-4610.PMID28822908.
  41. ^abElizabeth J. Weston; Yana Eglit; Alastair G. B. Simpson (6 October 2023). "Kaonashia insperata gen. et sp. nov., a eukaryotrophic flagellate, represents a novel major lineage of heterotrophic stramenopiles".Journal of Eukaryotic Microbiology.doi:10.1111/JEU.13003.ISSN1066-5234.WikidataQ123562228.
  42. ^Anna Cho; Denis V. Tikhonenkov; Gordon Lax; Kristina I. Prokina;Patrick J. Keeling(10 November 2023). "Phylogenomic position of genetically diverse phagotrophic stramenopile flagellates in the sediment-associated MAST-6 lineage and a potentially halotolerant placididean".Molecular Phylogenetics and Evolution.190:107964.doi:10.1016/J.YMPEV.2023.107964.ISSN1055-7903.PMID37951557.WikidataQ124719861.
  43. ^Adl SM, Bass D, Lane CE, Lukeš J, Schoch CL, Smirnov A, Agatha S, Berney C, Brown MW, Burki F, Cárdenas P, Čepička I, Chistyakova L, del Campo J, Dunthorn M, Edvardsen B, Eglit Y, Guillou L, Hampl V, Heiss AA, Hoppenrath M, James TY, Karnkowska A, Karpov S, Kim E, Kolisko M, Kudryavtsev A, Lahr DJG, Lara E, Le Gall L, Lynn DH, Mann DG, Massana R, Mitchell EAD, Morrow C, Park JS, Pawlowski JW, Powell MJ, Richter DJ, Rueckert S, Shadwick L, Shimano S, Spiegel FW, Torruella G, Youssef N, Zlatogursky V, Zhang Q (2019)."Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes".Journal of Eukaryotic Microbiology.66(1): 4–119.doi:10.1111/jeu.12691.PMC6492006.PMID30257078.
  44. ^Wetherbee R, Jackson CJ, Repetti SI, Clementson LA, Costa JF, van de Meene A, Crawford S, Verbruggen H (April 2019). "The golden paradox - a new heterokont lineage with chloroplasts surrounded by two membranes".J Phycol.55(2): 257–278.doi:10.1111/jpy.12822.hdl:11343/233613.PMID30536815.S2CID54477112.
  45. ^Medlin LK, Desdevises Y (2018)."Sequence analysis confirms a new algal class".Vie et Milieu/Life & Environment.
  46. ^Graf, Louis; Yoon, Hwan Su (21 July 2021). "Olisthodiscophyceae, the 17th heterokont algal class".Journal of Phycology.57(4): 1091–1093.doi:10.1111/jpy.13184.PMID34289104.S2CID236175098.
  47. ^Barcytė, Dovilė; Eikrem, Wenche; Engesmo, Anette; Seoane, Sergio; Wohlmann, Jens; Horák, Aleš; Yurchenko, Tatiana; Eliáš, Marek (2 March 2021)."Olisthodiscusrepresents a new class of Ochrophyta ".Journal of Phycology.57(4): 1094–1118.doi:10.1111/jpy.13155.hdl:10852/86515.PMID33655496.S2CID232101186.
  48. ^Graf L, Yang EC, Han KY, Küpper FC, Benes KM, Oyadomari JK, Herbert RJH, Verbruggen H, Wetherbee R, Andersen RA, Yoon HS (December 2020)."Multigene Phylogeny, Morphological Observation and Re-examination of the Literature Lead to the Description of the Phaeosacciophyceae Classis Nova and Four New Species of the Heterokontophyta SI Clade".Protist.171(6): 125781.doi:10.1016/j.protis.2020.125781.PMID33278705.S2CID227315556.
edit
Retrieved from "https://en.wikipedia.org/w/index.php?title=Stramenopile&oldid=1243251481"