Triticeae

Taxobox
name = Common wheat or bread wheat


name = Tribe: "Triticeae"
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Poales
familia = Poaceae
subfamilia = Pooideae
tribus = Triticeae
tribus_authority = L.
subdivision_ranks = Genera
subdivision = See text.

"Triticeae" is a tribe within the "Pooideae" subfamily of grasses that includes genera with many domesticated species. Major crop genera are found in this tribe including wheat (See Wheat taxonomy), barley, and rye; crops in other genera include some for human consumption and others used for animal feed or rangeland protection. Among the world's cultivated species this tribe has some of the most complex genetic histories. An example is bread wheat, which contains the genomes of three species, only one of them originally a wheat "Triticum" species. Seed storage proteins in "Triticeae" are implicated in various food allergies and intolerances.

"Triticeae" Genera

This list of tribes broadly follows that in [http://delta-intkey.com/grass/ Grass Genera of World] . Although there are taxonomic disagreements about the precise circumscription of some genera, this scheme is typical of those used in taxonomic literature. "Aegilops" ( [http://plants.usda.gov/java/profile?symbol=AEGIL goat grasses] - [http://plants.usda.gov/java/profile?symbol=AECY jointed goatgrass] , [http://plants.usda.gov/java/profile?symbol=AETA2 Tausch goatgrass] , etc)
"Agropyron" ("crested wheatgrasses" - [http://plants.usda.gov/java/profile?symbol=AGDE2 Desert wheatgrass] , [http://www.agf.gov.bc.ca/cropprot/weedguid/quackg.htm quackgrass] , etc)
"Amblyopyrum" (" [http://www.k-state.edu/wgrc/Germplasm/Aegilops/muticum.html Slim wheat grass] " - [http://plants.usda.gov/java/profile?symbol=AMBLY5 amblyopyrum] )
"Australopyrum" (Australian wheatgrasses - [http://delta-intkey.com/pooid/www/descr061.htm velvet wheatgrass] , [http://floraseries.landcareresearch.co.nz/pages/Taxon.aspx?id=_826dec51-e37d-49f7-a6bc-102c854c3342&fileName=Flora%205.xml pectinated wheatgrass] , etc)
"Cockaynea"
"Crithopsis" ( [http://www.kew.org/data/grasses-db/www/imp02570.htm "delileana" grass] )
"Dasypyrum" ( [http://plants.usda.gov/java/profile?symbol=DAVI2 Mosquito grass] )
" [http://plants.usda.gov/java/profile?symbol=ELYMU Elymus] " (wild ryes - [http://plants.usda.gov/java/profile?symbol=ELGL blue wildrye] , [http://plants.usda.gov/java/profile?symbol=ELIN6 Texas ryegrass] , etc)
"Elytrigia"
"Eremium" ( [http://delta-intkey.com/grass/www/eremium.htm Argentine desert ryegrass] )
"Eremopyrum" ( [http://plants.usda.gov/java/profile?symbol=EREMO5 false wheatgrasses] - [http://plants.usda.gov/java/profile?symbol=ERBO3 tapertip false wheatgrass] , [http://plants.usda.gov/java/profile?symbol=ERTR13 annual wheatgrass] , etc)
" [http://delta-intkey.com/grass/www/festucop.htm Festucopsis] "
" [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3606565&dopt=Abstract Haynaldia] "
" [http://delta-intkey.com/grass/www/henrardi.htm Henrardia] "
" [http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?18941 Heteranthelium] "
"Hordelymus"
"Hordeum" ( [http://plants.usda.gov/java/profile?symbol=HORDE barleys] - [http://plants.usda.gov/java/profile?symbol=HOVU common barley] , [http://plants.usda.gov/java/profile?symbol=HOJU foxtail barley] , etc)
"Hystrix" ( [http://plants.usda.gov/java/profile?symbol=ELHYH porcupine grass] - [http://spuds.agron.ksu.edu/ksgrasskey/images/Hystrixpatula.html bottlebrush grass] )
" [http://hua.huh.harvard.edu/china/novon/yenyabau8-1.htm Kengyilia] "
"Leymus" (wild rye- [http://www.laspilitas.com/plants/1193.htm American dune grass] , [http://www.plant-identification.co.uk/skye/gramineae/leymus-arenarius.htm lyme grass] ,etc)
"Lophopyrum" ( [http://plants.usda.gov/java/profile?symbol=THPO7 tall wheatgrass] )
"Malacurus"
"Pascopyrum"( [http://plants.usda.gov/java/profile?symbol=PASM western wheatgrass] )
" [http://herbarium.usu.edu/Triticeae/peridictyon.html Peridictyon] "
"Psathyrostachys" ( [http://plants.usda.gov/java/profile?symbol=PSJU3 Russian wildrye] )
" [http://herbarium.usu.edu/Triticeae/Pseudoroegneria.htm Pseudoroegneria] " ( [http://plants.usda.gov/java/profile?symbol=PSEUD22 bluebunch wheatgrasses] - [http://plants.usda.gov/java/profile?symbol=PSSPI beardless wheatgrass] , etc)
"Secale" (Ryes - [http://plants.usda.gov/java/profile?symbol=SECAL Cereal rye] , [http://www.pfaf.org/database/plants.php?Secale+sylvestre Himalayan Rye] ,etc)
"Sitanion"
" [http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?17566 Stenostachys] " (New Zealand wheatgrasses)
"Taeniatherum" ( [http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=TAENI2&display=63 medusahead] - [http://plants.usda.gov/java/ClassificationServlet?source=display&classid=TACA8 medusahead] )
" [http://plants.usda.gov/java/ClassificationServlet?source=display&classid=THINO Thinopyrum] " ( [http://plants.usda.gov/java/profile?symbol=THIN6 intermediate wheatgrass] , [http://plants.usda.gov/java/ClassificationServlet?source=display&classid=THJU3 Russian wheatgrass] , [http://plants.usda.gov/java/ClassificationServlet?source=display&classid=THPY4 thick quackgrass] )
"Triticum" (Wheats - common wheat, durum wheat, etc)

Cultivated or Edible Species

[
wheat gluten flour, European spelt, barley corns, rolled rye]

"Aegilops"

*Various species (rarely identifiable to species in archaeological material) occur in pre-agrarian archaeobotanical remains from Near Eastern sites. Their edible grains were doubtless harvested as wild food resources.
* "speltoides" - [http://www.ibiblio.org/pfaf/cgi-bin/arr_html?Aegilops+speltoides ancient food grain] , putative source of B genome in bread wheat and G genome in "T. timopheevii"
* "tauschii" - Source of D genome in wheat

"Amblyopyrum"

* "muticum" - Source of T genome.

"Elmyus"

Various species are cultivated for pastoral purposes or to protect fallowland from opportunistic or invasive species
* "canadensis" - [http://www.pfaf.org/database/plants.php?Elymus+canadensis edible, bread flour capable, fiddly seeds]
* "trachycaulus" - [http://www.hort.purdue.edu/newcrop/proceedings1999/v4-015b.html pastoral cultivar]

"Hordeum"

Many barley cultivars
* "vulgare" - common barley (6 subspecies, ~100 cultivars)
* "bulbosum" - [http://www.pfaf.org/database/plants.php?Hordeum+bulbosum edible seeds]
* "murinum" (mouse barley) - [http://www.pfaf.org/database/plants.php?Hordeum+murinum cooked as piñole, bread flour capable] , medicinal: diuretic.

"Leymus"

* "arenarius" (Lyme grass) - [http://www.pfaf.org/database/plants.php?Leymus+arenarius bread flour capable, possible food additive]
* "racemosus" (Volga Wild Rye) - [http://www.pfaf.org/database/plants.php?Leymus+racemosus drought tolerant cereal, used in Russia]
* "condensatus" (Giant Wild Rye) - [http://www.pfaf.org/database/plants.php?Leymus+condensatus Edible seeds, harvesting problematic small seeds]
* "triticoides" (Squaw grass) - [http://www.pfaf.org/database/plants.php?Leymus+triticoides used in North America, seed hairs must be singed]

"Secale"

Ryes
* "cereale" (Cereal Rye) - Livestock feed and sour dough bread - 6 subspecies.
* "cornutum"-ergot (Ergot of Spurred Rye) - herbal medicine at very low doses, [cite journal | author = Eadie M | title = Ergot of rye-the first specific for migraine. | journal = J Clin Neurosci | volume = 11 | issue = 1 | pages = 4–7 | year = 2004 | pmid = 14642357 | doi = 10.1016/j.jocn.2003.05.002] deadly poisonous as food.
* "strictum" - [http://www.pfaf.org/database/plants.php?Secale+strictum+kuprijanovii actively cultivated]
* "sylvestre" - (Tibetan Rye) - [http://www.pfaf.org/database/plants.php?Secale+sylvestre actively cultivated] in Tibet and China highlands.
* "vavilovi" (Armenian Wild Rye) - [http://www.pfaf.org/database/plants.php?Secale+vavilovii edible seeds, thickener] .

"Triticum"

(Wheat)
* "aestivum" (bread wheat) - (AABBDD Genome)
** "compactum" (club wheat)
** "macha" (hulled)
** "spelta" (hulled, spelt)
** "sphaerococcum" (shot wheat)
* "monococcum" (Einkorn wheat) (A Genome)
* "timopheevii" (Sanduri wheat)
* "turgidum" (poulard wheat) (AB Genome)
** "carthlicum" (Persian black wheat)
** "dicoccoides" (wild emmer wheat)
** "dicoccum" (cultivated emmer wheat) - used to make Farro
** "durum" (durum wheat)
** "paleocolchicum"
** "polonicum" (Polish wheat)
** "turanicum"
** "turgidum"

Genetics

"Triticeae" and its sister tribe "Bromeae" (possible cultivars: " [http://www.pfaf.org/database/plants.php?Bromus+mango Bromus mango] " S. America) when joined form a sister clade with "Poeae" and "Aveneae" (oats). Inter-generic gene flow characterized these taxa from the early stages. For example, "Poeae" and "Aveneae" share a genetic marker with barley and 10 other members of "Triticeae", whereas all 19 genera of "Triticeae" bear a wheat marker along with "Bromeae".cite journal | author = Kubo N, Salomon B, Komatsuda T, von Bothmer R, Kadowaki K | title = Structural and distributional variation of mitochondrial rps2 genes in the tribe Triticeae (Poaceae). | journal = Theor Appl Genet | volume = 110 | issue = 6 | pages = 995–1002 | year = 2005 | pmid = 15754209 | doi = 10.1007/s00122-004-1839-x] Genera within "Triticeae" contain diploid, allotetraploid and/or allohexaploid genomes, the capacity to form allopolyploid genomes varies within the tribe. In this tribe, the majority of diploid species tested are closely related to "Aegilops", the more distal members (earliest branch points) include "Hordeum" (Barley), "Eremian", "Psathyrostachys". The broad distribution of cultivars within the Tribe and the properties of the proteins have implication in the treatment of certain digestive diseases and autoimmune disorders.

Evolution of the Tribe

One of the earliest branches in "Triticeae", to "Psuedoroegeneria", produces the genome StSt and another "Hordeum" then genome = HH. Allotetraploid combinations of "Psuedoroegeneria" and "Hordeum" and are seen in "Elmyus" (HHStSt),cite journal | author = Mason-Gamer R | title = Reticulate evolution, introgression, and intertribal gene capture in an allohexaploid grass. | journal = Syst Biol | volume = 53 | issue = 1 | pages = 25–37 | year = 2004 | pmid = 14965898 | doi = 10.1080/10635150490424402] but also shows introgression from Australian and Agropyron wheatgrasses.cite journal | author = Liu Q, Ge S, Tang H, Zhang X, Zhu G, Lu B | title = Phylogenetic relationships in Elymus (Poaceae: Triticeae) based on the nuclear ribosomal internal transcribed spacer and chloroplast trnL-F sequences. | journal = New Phytol | volume = 170 | issue = 2 | pages = 411–20 | year = 2006 | pmid = 16608465 | doi = 10.1111/j.1469-8137.2006.01665.x] Elymus contains mostly "Psuedoroegeneria" mtDNA.cite journal | author = Mason-Gamer R, Orme N, Anderson C | title = Phylogenetic analysis of North American Elymus and the monogenomic Triticeae (Poaceae) using three chloroplast DNA data sets. | journal = Genome | volume = 45 | issue = 6 | pages = 991–1002 | year = 2002 | pmid = 12502243 | doi = 10.1139/g02-065]

Many genera and species of "Triticeae" are exemplary of allopolyploids, having more chromosomes than seen in typical diploids. Typically allopolyploids are tetraploid or hexaploid, XXYY or XXYYZZ. The creation of polyploid species results from natural random events tolerated by polyploid capable plants. Likewise natural allopolyploid plants may have selective benefits and may allow the recombination of distantly related genetic material facilitating at a later time a reversion back to diploid. Poulard wheat is an example of a stable allotetraploid wheat.

The "Secale" (domesticated rye) may be a very early branch from the goat grass clad (or goat grasses are a branch of early rye grasses), as branch these are almost contemporary with the branching between monoploid wheat and "Aegilops tauschii". Studies in Anatolia now suggest Rye ("Secale") was cultivated, but not domesticated, prior to the holocene and to evidence for the cultivation of wheat. As climate changed the favorablitiy of "Secale" declined. At that time other strains of barley and wheat may have been cultivated, but humans did little to change them.

Goat Grasses and the Evolution of Bread Wheat

Tetraploidation in Wild Emmer Wheat

"Aegilops" appears to be basal to several taxa such as "Triticum", "Ambylopyrum", and "Crithopsis". Certain species such as "Aegilops speltoides" could potentially represent core variants of the taxa. The generic placement may be more a matter of nomenclature. "Aegilops" and "Triticum" genera are very closely related as the image to the right illustrates the "Aegilops" species occupy most of the basal branch points in bread wheat evolution indicating that "Triticum" genus evolved from Aegilops after an estimated 4 million years ago.cite journal | author = Dvorak J, Akhunov ED, Akhunov AR, Deal KR, and Luo MC | title = Molecular characterization of a diagnostic DNA marker for domesticated tetraploid wheat provides evidence for gene flow from wild tetraploid wheat to hexaploid wheat. | journal = Mol Biol Evol. | volume = 23 | issue = 7 | pages = 1386–1396 | year = 2006 | pmid = 16675504 | doi = 10.1093/molbev/msl004] The divergence of the genomes is followed by allotetraploidation of a speltoid goatgrass x basal wheat species "Triticum boeoticum" with strains in the middle eastern region giving rise to cultivated emmer wheat.>cite journal | author = Heun M, Schäfer-Pregl R, Klawan D, Castagna R, Accerbi M, Borghi B, and Salamini F | title = Site of Einkorn Wheat Domestication Identified by DNA Fingerprinting. | journal = Science | volume = 278 | issue = 5341 | pages = 1312–1314 | year = 1997 | id = | doi = 10.1126/science.278.5341.1312]

Hexaploidation of tetraploid wheat

[http://www.ipgri.cgiar.org/Publications/HTMLPublications/47/ch10.htm Hybridization] of tetraploid wheat with "Ae. tauschii" produced a hulled wheat similar to spelt, suggesting "T. spelta" is basal. The "tauschii" species can be subdivided into subspecies "tauschii" (eastern Turkey to China or Pakistan) and "strangulata" (Caucasus to S. Caspian, N. Iran). The D genome of bread wheat is closer to "A.t. strangulata" than "A.t. tauschii". It is suggested that "Ae. tauschii" underwent rapid selective evolution prior to combining with tetraploid wheat.

Wild "Triticeae" use by humans

Intense use of wild "Triticeae"' can be seen in the Levant as early as 23,000 years ago.cite journal | author = Weiss E, Wetterstrom W, Nadel D, Bar-Yosef O | title = The broad spectrum revisited: evidence from plant remains. | journal = Proc Natl Acad Sci USA | volume = 101 | issue = 26 | pages = 9551–5 | year = 2004 | pmid = 15210984 | doi = 10.1073/pnas.0402362101] This site, Ohala II (Israel), also shows that "Triticeae" grains were processed and cooked.cite journal | author = Piperno D, Weiss E, Holst I, Nadel D | title = Processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis. | journal = Nature | volume = 430 | issue = 7000 | pages = 670–3 | year = 2004 | pmid = 15295598 | doi = 10.1038/nature02734] Many cultivars appear to have been domesticated in the region of the upper Fertile Crescent, Levant and central Anatolia.cite journal | author = Lev-Yadun S, Gopher A, and Abbo S | title = (ARCHAEOLOGY:Enhanced:) The Cradle of Agriculture. | journal = Science | volume = 288 | issue = 5471 | pages = 1602–1603 | year = 2000 | doi = 10.1126/science.288.5471.1602 | pmid = 10858140] cite journal | author = Weiss E, Kislev ME, and Hartmann A | title = (Perspectives-Anthropology:) Autonomous Cultivation Before Domestication. | journal = Science | volume = 312 | issue = 5780 | pages = 1608–1610 | year = 2006 | doi = 10.1126/science.1127235 | pmid = 16778044] More recent evidence suggests that cultivation of wheat from emmer's wheatrequired a longer period with wild seeding maintaining a presence in archaeological finds.cite journal | author = Balter M | title = Seeking Agriculture's Ancient Roots | journal = Science | volume = 316 | pages = 1830–1835 | year = 2007 | doi = 10.1126/science.316.5833.1830 | pmid = 17600193]

Pastoral Grasses

"Triticeae" has a pastoral component that some contend goes back to the Neolithic period and is referred to as the [http://www.princeton.edu/~bogucki/mosaic.html Garden Hunting Hypothesis] . In this hypothesis grains could be planted or shared for the purpose of attracting game animals so that they could be hunted close to settlements.

Today, rye and other "Triticeae" cultivars are used to grazing animals, particularly cattle.Rye grasses in the New World have been used to selectively for use as fodder, but alsoto protect grasslands without the introduction of invasive old world species.

Triticeae and health

Glutens (storage proteins) in the "Triticeae" tribe have been linked to gluten-sensitive diseases. While it was once believed that [oat] s carried similar potentials, recent studies indicate that most-oat sensitivity is the result of contamination. Triticeae glutens examines of the proteins of "Triticeae", important in the link between gluten, gastrointestinal, allergic and autoimmune diseasescite journal |author=Silano M, Dessì M, De Vincenzi M, Cornell H |title=In vitro tests indicate that certain varieties of oats may be harmful to patients with coeliac disease |journal=J. Gastroenterol. Hepatol. |volume=22 |issue=4 |pages=528–31 |year=2007 |pmid=17376046 |doi=10.1111/j.1440-1746.2006.04512.x] Some of the recently discovered biochemical and immunochemical properties of these proteins suggest they evolved for protection against dedicated or continuous consumption by mammalian seed eaters.cite journal |author=Mamone G, Ferranti P, Rossi M, "et al" |title=Identification of a peptide from alpha-gliadin resistant to digestive enzymes: Implications for celiac disease |journal= Journal of Chromatography B|volume= 855|issue= |pages= 236|year=2007 |pmid=17544966 |doi=10.1016/j.jchromb.2007.05.009] cite journal |author=Shan L, Qiao SW, Arentz-Hansen H, "et al" |title=Identification and analysis of multivalent proteolytically resistant peptides from gluten: implications for celiac sprue |journal=J. Proteome Res. |volume=4 |issue=5 |pages=1732–41 |year=2005 |pmid=16212427 |doi=10.1021/pr050173t] One recent publication even raises doubts about wheat's safety for anyone to eatcite journal |author=Bernardo D, Garrote JA, Fernández-Salazar L, Riestra S, Arranz E |title=Is gliadin really safe for non-coeliac individuals? Production of interleukin 15 in biopsy culture from non-coeliac individuals challenged with gliadin peptides |journal=Gut |volume=56 |issue=6 |pages=889–90 |year=2007 |pmid=17519496 |doi=10.1136/gut.2006.118265] Overlapping properties with regard to food preparation have made these proteins much more useful as cereal cultivars and a balanced perspective suggest a variable tolerance to "Triticeae" glutens reflects early childhood environment and genetic predisposition.cite journal | author = Collin P, Mäki M, Kaukinen K | title = Safe gluten threshold for patients with celiac disease: some patients are more tolerant than others | journal = Am. J. Clin. Nutr. | volume = 86 | issue = 1 | pages = 260; author reply 260–1 | year = 2007 | pmid = 17616789 | doi = ] cite journal | author = Guandalini S | title = The influence of gluten: weaning recommendations for healthy children and children at risk for celiac disease | journal = Nestlé Nutrition workshop series. Paediatric programme | volume = 60 | issue = | pages = 139–55 | year = 2007 | pmid = 17664902 | doi = 10.1159/0000106366 | doi_brokendate = 2008-10-03] cite journal | author = Bao F, Yu L, Babu S, "et al" | title = One third of HLA DQ2 homozygous patients with type 1 diabetes express celiac disease-associated transglutaminase autoantibodies | journal = J. Autoimmun. | volume = 13 | issue = 1 | pages = 143–8 | year = 1999 | pmid = 10441179 | doi = 10.1006/jaut.1999.0303] cite journal | author = Zubillaga P, Vidales MC, Zubillaga I, Ormaechea V, García-Urkía N, Vitoria JC | title = HLA-DQA1 and HLA-DQB1 genetic markers and clinical presentation in celiac disease | journal = J. Pediatr. Gastroenterol. Nutr. | volume = 34 | issue = 5 | pages = 548–54 | year = 2002 | pmid = 12050583 | doi =10.1097/00005176-200205000-00014 ]

References

Links

* [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=147389 Pubmed:Triticeae]

* [http://www.pfaf.org/database/search_use.php Database of Edible Seed Plants]

* [http://www.ipgri.cgiar.org/Publications/HTMLPublications/47/ch01.htm#TopOfPage International Center for Agricultural Research in the Dry Areas (ICARDA)] - An excellent resource for the ancestral genetics of "Triticeae".

* [https://www.ksu.edu/wgrc/Taxonomy/compaeg.html Aegilops (genome) Comparative Classification Table]

* [https://www.ksu.edu/wgrc/Taxonomy/comptri.html Triticum (genome)Comparative Classification Table]

* [http://herbarium.usu.edu/Triticeae/genomesaegilops.htm Genomes in Aegilops, Triticum, and Amblyopyrum]

* [http://data.jic.bbsrc.ac.uk/cgi-bin/germplasm/triticeae/ Triticeae germplasm]