NationMaster - Encyclopedia: Triticeae

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. Miracle wheat (Triticum turgidum var. ... Binomial name L. Barley (Hordeum vulgare) is an annual cereal grain, which serves as a major animal feed crop, with smaller amounts used for malting and in health food. ... Binomial name Secale cereale M.Bieb. ... Species T. monococcum T. spelta References: ITIS 42236 2002-09-22 Wheat (Triticum spp) is a grass that is cultivated around the world. ... A food allergy is an immunologic response to a food protein. ...

Triticeae Genera

This list of tribes broadly follows that in 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 (goat grasses - jointed goatgrass, Tausch goatgrass,ovate goatgrass,barbed goatgrass, Persian goatgrass, etc)
Agropyron (crested wheatgrasses - Desert wheatgrass, quackgrass,western wheatgrass, etc)
Amblyopyrum (Slim wheat grass - amblyopyrum)
Australopyrum (Australian wheatgrasses - velvet wheatgrass,pectinated wheatgrass, etc)
Cockaynea
Crithopsis (delileana grass)
Dasypyrum (Mosquito grass)
Elymus (wild ryes - blue wildrye,squirreltail ryegrass,Texas ryegrass, etc) (Genome = StH)
Elytrigia
Eremium (Argentine desert ryegrass)
Eremopyrum (false wheatgrasses - tapertip false wheatgrass,Oriental false wheatgrass,annual wheatgrass, etc)
Festucopsis
Haynaldia
Henrardia
Heteranthelium
Hordelymus
Hordeum (barleys - common barley, arizona barley,foxtail barley, etc) (genome = H)
Hystrix (porcupine grass- bottlebrush grass)
Kengyilia
Leymus (wild rye- American dune grass,lyme grass,creeping rye,etc)
Lophopyrum (tall wheatgrass)
Malacurus
Pascopyrum(western wheatgrass)
Peridictyon
Psathyrostachys (Russian wildrye)
Pseudoroegneria (bluebunch wheatgrasses - bluebunch wheatgrass, beardless wheatgrass, etc) (Genome = St)
Secale (Ryes - Cereal rye, Himalayan Rye, Montana Rye,etc)
Sitanion
Stenostachys (New Zealand wheatgrasses) (Genome HW)
Taeniatherum (medusahead - medusahead)
Thinopyrum (intermediate wheatgrass, Russian wheatgrass, tall wheatgrass,thick quackgrass)
Triticum (Wheats - common wheat, durum wheat, etc)
Species See text Aegilops is a genus of plants belonging to the family Graminaceae. ... Species See text Agropyron is a genus of grasses (family Poaceae). ... Hordeum is a genus of about 30 species of annual and perennial grasses, native throughout the temperate Northern Hemisphere, temperate South America, and also South Africa. ... species Leymus arenarius - sand ryegrass Leymus aristiglumus Leymus cinereus Leymus condensatus - giant wild rye Leymus divaricatus Leymus flexus Leymus mollis mollis - American dune grass Leymus obvipodus Leymus pendulus Leymus triticoides - creeping wild rye Leymus is a genus of the true grass family (Poaceae). ... species Leymus arenarius - sand ryegrass Leymus aristiglumus Leymus cinereus Leymus condensatus - giant wild rye Leymus divaricatus Leymus flexus Leymus mollis mollis - American dune grass Leymus obvipodus Leymus pendulus Leymus triticoides - creeping wild rye Leymus is a genus of the true grass family (Poaceae). ... Binomial name Secale cereale References: ITIS 42089 2002-09-22 Rye (Secale cereale) is a grass grown extensively as a grain and forage crop. ... Species T. monococcum T. spelta References: ITIS 42236 2002-09-22 Wheat (Triticum spp) is a grass that is cultivated around the world. ... Binomial name Triticum aestivum L. Common wheat (also known as bread wheat) is by far the most important wheat species in cultivation today. ... Durum wheat (Triticum turgidum durum) is the only tetraploid species of wheat widely cultivated today. ...

Cultivated or Edible Species

Aegilops

Amblyopyrum

Elmyus

Various species are cultivated for pastoral purposes or to protect fallow land from opportunistic or invasive species

Hordeum

Leymus

Secale

Triticum

Binomial name Triticum spelta L. Spelt (Triticum spelta) was an important wheat species in parts of Europe from the Bronze Age to medieval times. ... Binomial name Triticum timopheevii Zhuk. ... Binomial name Triticum dicoccon Schrank Emmer wheat is a low yielding, awned wheat. ... Durum wheat (Triticum turgidum durum) is the only tetraploid species of wheat widely cultivated today. ...

Genetics

Triticeae and its sister tribe Bromeae (possible cultivars: 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.^[2] Genera within Triticeae contain diploid, allotetraploid and/or allohexaploid genomes, the capacity for 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.

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.^[3] The divergence of the genomes is followed by allotetraploidation of a speltoid goatgrass x basal wheat species Triticum boeoticum with populations in the middle eastern region giving rise to cultivated emmer wheat.^[4]

Hexaploidation of tetraploid wheat

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 strangulata than tauschii. It is suggested that Ae. tauschii. underwent rapid selective evolution prior to combining with tetraploid wheat.

Evolution of distal taxa

While it might be tempting to think that since Hordeum and Triticum were domesticated proximally, that these two crop plants are closely related within Triticeae. 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. The Secale 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. Binomial name Secale cereale References: ITIS 42089 2002-09-22 Rye (Secale cereale) is a grass grown extensively as a grain and forage crop. ... The Holocene epoch is a geological period that extends from the present day back to about 10,000 radiocarbon years, approximately 11,430 Â± 130 calendar years BP (between 9560 and 9300 BC). ...

More distantly related are the Australian wheatgrasses. One of the earliest branches in Triticeae produces the Psuedoroegeneria (Genome = StSt) and another Hordeum (Genome = HH) genera. Allotetraploid crosses with Hordeum and are seen in Elmyus (HHStSt),^[5] but also shows introgression from Australian and Agropyron wheatgrasses.^[6] Elymus contains mostly Psuedoroegeneria mtDNA.^[7] Like other polyploid genomic Triticeae, Elymus represents also a number of prospective cultivars. Thus Hordeum cultivatable properties are not necessarily tied to the middle east or wheat domestication, and its relatively early branchpoint relative to Aegilopoides and derivatives indicate relatively independent evolution for millions of years. Hordeum is a genus of about 30 species of annual and perennial grasses, native throughout the temperate Northern Hemisphere, temperate South America, and also South Africa. ...

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.

Human cultivation adds artificial selection (human preference) to bring naturally produced allopolyploid strains into widespread cultivation. Genetic studies of Aegilopoidic species indicate that cultivating and selecting grasses prior to crossing (removing the undesirable traits in both stains) is one possibly way to simplify selection on the allopolyploid products. Bread Wheat (Triticum aestivum) is an example of human preference acting on a random allopolyploidation AABB X DD to produce a new species of wheat, T. aestivum, with the allohexaploid genome AABBDD.

The process of allopolyploidation and selecting increased the level and diversity of expressed proteins. T. aestivum contains a larger proportion of these proteins. A prefered set of cultivars because of the level of digestible protein and because these proteins facilitate bread making, having the drawback also of combining sensitizing proteins and increasing levels of these proteins. T. aestivum is the result of the combining of genomes from several Triticeae 'species' within a single species each genome producing a different but similar set of proteins. T. aestivum domestication demostrates the benefit of increasing genomes as a means of enriching certain seed qualities. The process also benefits the reduction of genes that interfere with industrial processing.

Wild Triticeae use by humans

Intense use of wild Triticeae' can be seen in the Levant as early as 23,000 years ago.^[8] This site, Ohala II (Israel), also shows that Triticeae grains were processed and cooked.^[9] Many cultivars appear to have been domesticated in the region of the upper Fertile Crescent, Levant and central Anatolia.^[10]^[11]

Pastoral Grasses

Triticeae has a pastoral component that some contend goes back to the Neolithic period and is referred to as the 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. Titians The Pastoral Concert Pastoral refers to the lifestyle of shepherds and pastoralists, moving livestock around larger areas of land according to seasons and availability of water and feed. ...

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 also to protect grasslands without the introduction of invasive old world species.

Triticeae and health

Glutens (storage proteins) in the Triticeae tribe have been linked with certainty to coeliac disease, certain complex allergic reactions and controversaly to other conditions. Triticeae glutens examines of the proteins of Triticeae, important in the link between gluten, gastrointestinal, allergic and autoimmune diseases that are primarily focused on the glutens of Wheat, Rye and Barley, but may also be triggered by similar proteins in Aveneae species or subspecies.^[12] 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.^[13]^[14] One recent publication even begs the question is wheat safe for anyone to eat?^[15] 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. Triticeae glutens are seed storage proteins found in mature seeds of grass tribe Triticeae. ... Gluten sensitivity describes the collection of medical conditions in which the patient responds favorably, either directly or indirectly, to the removal of gluten from the diet. ...

References

^ Eadie M (2004). "Ergot of rye-the first specific for migraine.". J Clin Neurosci 11 (1): 4-7. PMID 14642357.
^ Kubo N, Salomon B, Komatsuda T, von Bothmer R, Kadowaki K (2005). "Structural and distributional variation of mitochondrial rps2 genes in the tribe Triticeae (Poaceae).". Theor Appl Genet 110 (6): 995-1002. PMID 15754209.
^ Dvorak J, Akhunov ED, Akhunov AR, Deal KR, and Luo MC (2006). "Molecular characterization of a diagnostic DNA marker for domesticated tetraploid wheat provides evidence for gene flow from wild tetraploid wheat to hexaploid wheat.". Mol Biol Evol. 23 (7): 1386-1396. PMID 16675504.
^ >Heun M, Schäfer-Pregl R, Klawan D, Castagna R, Accerbi M, Borghi B, and Salamini F (1997). "Site of Einkorn Wheat Domestication Identified by DNA Fingerprinting.". Science 278 (5341): 1312-1314.
^ Mason-Gamer R (2004). "Reticulate evolution, introgression, and intertribal gene capture in an allohexaploid grass.". Syst Biol 53 (1): 25-37. PMID 14965898.
^ Liu Q, Ge S, Tang H, Zhang X, Zhu G, Lu B (2006). "Phylogenetic relationships in Elymus (Poaceae: Triticeae) based on the nuclear ribosomal internal transcribed spacer and chloroplast trnL-F sequences.". New Phytol 170 (2): 411-20. PMID 16608465.
^ Mason-Gamer R, Orme N, Anderson C (2002). "Phylogenetic analysis of North American Elymus and the monogenomic Triticeae (Poaceae) using three chloroplast DNA data sets.". Genome 45 (6): 991-1002. PMID 12502243.
^ Weiss E, Wetterstrom W, Nadel D, Bar-Yosef O (2004). "The broad spectrum revisited: evidence from plant remains.". Proc Natl Acad Sci U S A 101 (26): 9551-5. PMID 15210984.
^ Piperno D, Weiss E, Holst I, Nadel D (2004). "Processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis.". Nature 430 (7000): 670-3. PMID 15295598.
^ Lev-Yadun S, Gopher A, and Abbo S (2000). "(ARCHAEOLOGY:Enhanced:) The Cradle of Agriculture.". Science 288 (5471): 1602-1603.
^ Weiss E, Kislev ME, and Hartmann A (2006). "(Perspectives-Anthropology:) Autonomous Cultivation Before Domestication.". Science 312 (5780): 1608-1610.
^ Silano M, Dessì M, De Vincenzi M, Cornell H (2007). "In vitro tests indicate that certain varieties of oats may be harmful to patients with coeliac disease". J. Gastroenterol. Hepatol. 22 (4): 528-31. DOI:10.1111/j.1440-1746.2006.04512.x. PMID 17376046.
^ Mamone G, Ferranti P, Rossi M, et al (2007). "Identification of a peptide from alpha-gliadin resistant to digestive enzymes: Implications for celiac disease". DOI:10.1016/j.jchromb.2007.05.009. PMID 17544966.
^ Shan L, Qiao SW, Arentz-Hansen H, et al (2005). "Identification and analysis of multivalent proteolytically resistant peptides from gluten: implications for celiac sprue". J. Proteome Res. 4 (5): 1732-41. DOI:10.1021/pr050173t. PMID 16212427.
^ Bernardo D, Garrote JA, Fernández-Salazar L, Riestra S, Arranz E (2007). "Is gliadin really safe for non-coeliac individuals? Production of interleukin 15 in biopsy culture from non-coeliac individuals challenged with gliadin peptides". Gut 56 (6): 889-90. DOI:10.1136/gut.2006.118265. PMID 17519496.

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Contents

Triticeae Genera

Cultivated or Edible Species

Aegilops

Amblyopyrum

Elmyus

Hordeum

Leymus

Secale

Triticum

Genetics

Goat Grasses and the Evolution of Bread Wheat

Tetraploidation in Wild Emmer Wheat

Hexaploidation of tetraploid wheat

Evolution of distal taxa

Wild Triticeae use by humans

Pastoral Grasses

Triticeae and health

References

Links

Contents

Triticeae Genera GA_googleFillSlot("encyclopedia_square");

Cultivated or Edible Species

Aegilops

Amblyopyrum

Elmyus

Hordeum

Leymus

Secale

Triticum

Genetics

Goat Grasses and the Evolution of Bread Wheat

Tetraploidation in Wild Emmer Wheat

Hexaploidation of tetraploid wheat

Evolution of distal taxa

Wild Triticeae use by humans

Pastoral Grasses

Triticeae and health

References

Links

Triticeae Genera