Negi Springfield and Triticeae: Difference between pages

Tribe: Triticeae
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Poales
Family:	Poaceae
Subfamily:	Pooideae
Genera
See text.

Triticeae is a taxonomical tribe of Pooideae grasses that includes several common domesticated species. These domesticated cultivars are: Wheat (See Wheat Taxonomy), Barley, Rye, Spelt. Amoung the worlds cultivars this group appears to have some of the most complex genetics, epitomized by bread wheat which appears to have the genomes of three species only one of them originally a wheat species.

Triticeae Genera

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)
Critesion (knee barley- Foxtail barley,etc)
Crithodium (wild einkorn wheat)
Crithopsis (delileana grass)
Dasypyrum (Mosquito grass)
Elymus (wild ryes - blue wildrye,squirreltail ryegrass,E. bottlebrush ryegrass,Texas ryegrass, etc)
Eremium (Argentine desert ryegrass)
Eremopyrum (false wheatgrasses - tapertip false wheatgrass,Oriental false wheatgrass,annual wheatgrass, etc)
Festucopsis
Haynaldia
Henrardia
Heteranthelium
Hordeum (barleys)
Hystrix
Kengyilia
Leymus (wild rye)
Lophopyrum (tall wheatgrass)
Pascopyrum
Peridictyon
Psammopyrum
Psathyrostachys
Pseudoroegneria (beardless wheatgrass)
Secale (Ryes)
Stenostachys
Taeniatherum
Thinopyrum
Triticum (Wheats)

Cultivated or Edible Species

Aegilops

• markgrafii - ancient cultivar or edible seed grass? Source of the M genome
• triuncialis - edible, poor harvesting
• speltoides - edible, poor harvesting, source of B genome in bread wheat, source of G genome in T. timopheevii
• tauschii - ancient cultivar or edible seed grass? Source of D genome in wheat
• umbellulata - ancient cultivar or edible seed grass? Source of U genome

Amblyopyrum

• muticum - ancient cultivar or edible seed grass? Source of T genome

Critesion

• geniculatum - edible poor harvesting

Crithodium

• monococcum aegilopoides - edible poor harvesting, basis of wheat or source of wheat A genome.

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

• canadensis - Edible, breadable flour, fiddly seeds
• trachycaulus - pastorla cultivar

[In progress] . . . . . . .

Goat Grasses and the Evolution of Bread Wheat

File:BreadWheatEvolution.JPG

Evolution of Bread Wheat

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 an estimated 4 million years ago . Aegilops is populated by a number of nondescript goat grasses.

Triticeae Proteins

Grass Storage Proteins - the Glutens Storage Proteins:

• albumins - soluble in hypotonic solutions and are coagulated by heat
• globulins - soluble on 'isotonic' solutions
• prolamins - alcohol in aqueous alcohol
• glutelins - are soluble in dilute acid or bases, detergents, choatrophic or reducing agents.

Glutens are elastic, glue capable proteins derived from seed grasses. Seed Gluten of non-Triticeae plants have a varieties of properties, but none singly can perform on a par with those of the Triticeae taxa, particularly the triticum species (bread wheat, durum wheat).

Proteins of the Endosperm that are rich in Arginine, Proline, and Asparagine.

• Prolamins
  • Triticum (True Wheats) - gliadins
  • Hordeum (Food Barleys) - hordeins
  • Secalum (Food Ryes) - secalins
• glutelins
  • Triticum - glutenin

Gliadin as an example of the Prolamines in Triticeae.

• α/β gliadins - soluble in low percentage alcohols.
  • A1-α gliadin (Encoded by C. m. aegilopoides genome A)
  • Other
• ω gliadins - soluble in higher percentages, 30% - 50% acidic acetonitrile.

(Wheat has three genomes and it can encode for many variations of the same protein, even in the gliadin subcatagories many types of gliadin per cultivar, X = genome (A,B, D))

Glutenin as an example of Glutelins

• Forms long covelantly interlinked polymers of two repeating subunits.
  • Low Molecular Weight - α gliadin-like polypeptide
  • High Molecular Weight - proline-less (loci Chromosome 1, Glu-X1)

Gluten and Industry Glutens are an essential part of the modern food industry. The industry of wheat goes back to before the Neolithic period when people process grains, during the early phase wheats were selected for their harvestability and growability under various climate conditions. This industry spread into many areas of western eurasia by 7000 years ago, carrying the more primative cultivars. These grains were capable of being used for soups (speltiods) or simple flours and baked goods. During the second phase Emmers wheat was produced that and this contained more gluten making baking more efficient, one variant of Emmers wheat is called Durum Wheat and is the source of seminola flour, used in making pastas and other food pastes. Comparable varieties are found through out Eurasia. Finally, Emmers wheat was combined with Taush's goat grass to form what we call bread wheat. The industrial properties of this wheat are based in its glutens, glutens of high elasticity, high heat tolerance of other glutens or that change when subjected to heat to produce stronger polymers.

Comparing wheat gluten with corn (Zea) glutens. Corn is prepared for breading by boiling in water with alkali, resulting in a de-skinned material called masa. Masa can be used for industrial purposes (tortillas, tamales, chips), but it must be used quickly because its glutens change rapidly and binding decreases rapidly. Masa does not store well and chemicals are added to enhance preservation at the expense of quality. At its peak attempting to use masa as dough generally results in a crumbly flat bread, correctable by regrinding masa to a fine flour and adding gums (such as Xanthum gum) corn will never achieve the refined smoothness and silkiness of bread flour. There is a developing Gluten Free food industry that is developing corn flour for the purpose for wheat-food replacement. Masa, of course, can be considered an industrial grain for other reasons, despites its shortcoming it can be combined with fat to make tamales (and wrapped in leaves for storage life of several days), or to make tortillas that wrapped other foods and packaged. While masa is suitable as a flatbread flour in rural communities within major cities were people cannot grind and prepare masa on a daily basis masa quickly falls out of favor in masa utilizing cultures and is replaced by wheat comparables like wheat flour tortillas.

Important Trticeae Composites Wheat, however, has been far more exploited in history. When the flour is combined with water and yeast the dough can be risen and subsequently fixed by heat resulting in a hard outer shell with a soft palatable interior. This makes bread amicable for both transport and preserves the bread for several days (in dry conditions). Barley can be sprouted for a short period and roasted, the resulting malt can be ground for food or combined with bread yeast (currently a brewers variety) to produce beer and distilled spirits such as whiskey, vodka and sour dough malts. Adding egg to T. durum semolina flour can be used to make pastas, or a variant used to make chinese dumplings. Wheat or semolina flour can be added other ingredients such as fish, meat or milk to create food pastes. Wheat can be further processed to a very fine flour and sifted, alternatively the glutens either can be extracted and readded to other products. While many seed glutens and food gums when combined with food starch, come close to creating the refined products of wheat flour and durum flour, no combination can come close to the qualities of these flours at a comparable price.

Glutens are generated by the wheat starch industry. Glutens however are more difficult to handle once starch and other proteins are removed, for example alcohol soluble glutens cannot be mixed with dairy since the alcohol denatures and precipitates dairy proteins. Gluten is often modified for commercial use. Deamidation of Gliadin Gluten can be deamidated by treatment with acid at high temperatures, or enzymatic treatment with deamidase or transglutaminases. The increase charge increases the hydrophilicity of gliadins causing them to stretch out in solution. 20% of the Glutamines side chains to glutaminate is required to generate a soluble product. This renders gluten soluble enough to mix with other products like milk. The unintended consequence of deamidation is to render products more immunogenic to gluten sensitive indivdiuals, it could be a factor in the rise of adult onset gluten sensitivity.

The Bad, The Goods and the Sloppy
One of general problems of Triticeae glutens in their solubility (or lack thereof). Glutens represent the pute water insoluble component of grains, and gliadins, particularly gamma and omega gliadins represent relatively insoluble proteins. Strong organic solvents such as acidic acetonitrile between 25 and 40% are required to solubilize omega gliadin from the carbohydrate bulk of ground wheat. In addition certain regions of the prolamines are indigestable. In α-gliadin there is a 33-mer that is apparently not digested and contains a single immunogenic(cellular) motif as well as 3 internal motifs. These properties of the gliadins also make them excellent glues which are required for making refined pastas, food pastes, high quality baked goods and even pastes for school children. As a result wheat glutens are creeping into foods worldwide (and the labeling often does not 'catch-up') in an effort to make regional foods competitive in internal and international markets. Unfortunately, for people with food allergies and intolerances the labeling and announcement of these changes in product labels is not as rigorously enforced as in western nations. Other products, such as soy sauces, wheat ferments are added a flavoring agent, and in many of these sauces the wheat flour exceeds soy flour in the starting materials. The wheat-free alternatives are often very expensive. The sticky quality of gliadins is also exploited, for example, in production apparently wheat-free foods such a corn and potatoe chips, but have triticeae gluten added to during processing so that flavoring agents will stick to the product during and after processing. Since the unflavored products are processed on the same equipment as flavored products these products may variably have sufficient gluten to cause a reaction in sensitive individuals, and in GSE support groups the incidences of being 'glutened' is commonly reported for foods supposedly free of gluten.

There are still other forms of wheat 'creep', the most notorious example that GSE sufferers are aware of is Oats. Packagers of oats have identified the sources of wheat as uncleaned transport trucks and storage bins. Another source is free seeding wheat rye or barley in feilds in which crops are rotated. So bad is the 'creep' of wheat in the western oat supply that science cannot absolutely descriminate whether Oats mediate GSE or whether it is the wheat contaminants in Oats that mediates CD. In studies of children in Finland with GSE, the most severe and life threatening form, an oat replacement diet has been effective in treating GSE and thus it is likely that wheat contamination is the principle source of oat reactivity. One exception could be allergic diseases or even intolerant diseases mediated by ω-gliadin like proteins abundant in Oats.

Triticeae and Human Evolution

Intense use of wild Triticeae can be seen in the Levant as early as 23,000 years ago.

Einkorn Wheat still grows naturally in many areas of Eurasia, it is very hardy variety of wheat and was also domesiticated and cultivated for use in areas were Quadraploid and Hexaploid wheats grew poorly, such as in europes early neolithic LBK period.

Emmers Wheat (A quadraploid) appears to have been domesticated about 10,000 years ago in SE Turkey around the city of Gaizantep. Emmers wheat and, to a lessor degree, Einkorn Cultivars appear to be the prinicple cereals involved in the Neolithization of Central Europe and western europe.

Rye was originally domesticated in the Levant, but the early lines went out of cultivation. It was redomesticated in prehistoric Germany. Rye is more cold tolerant and drought tolerant than wheat.

Barley was domesticated about the same time as Wheat in the Levant. Barley appears to have been critical in the Neolithization of Scandinavia and distal parts of the British Ilses.

Bread Wheat (hexaploid, genomes include emmers wheat and goat grass genomes) appears to have been domesticate in ancient Armenia around 8,500 years ago. While bread wheat was domesticated before the neolithization of distal parts of europe, earlier strains of Triticum were primarily used during the early neolithic, this may reflect the increased demand for farming technologies that bread wheat requires

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. Today rye and other Triticeae cultivars are used to grazing animals, particularly cattle.

Triticeae and Human Disease

Rather than have a section for each Triticeae cultivar, all known medical conditions linked to all cultivars are placed in this section. It is not clear for instance which pathogenic isoforms in bread wheat come from Aegilops, Crithodium, or Triticum, and similar proteins exist in barley and rye, paraphyletic to the bread wheat taxonomy (see Image below). If there are any sufficient divisions between these proteins in the Triticeae clad that might result in adequat substitution to modulate downward the conditionally pathogenic effects. From the standpoint of individual being treated on a wheat-free diet it is fair to assume all triticeae cultivars have these conditionally pathogenic proteins and this may include grass seeds of sister taxa.

Coeliac Disease and Triticeae
Cultivars of Triticeae can induced Gluten Sensitive Enteropathy (GSE) in susceptible individuals. The incidence rate is about 1:100 lifelong risk in most western populations and is one of the most common autoimmune diseases. While considered by some to be an allergic disease, the effects of wheat gliadin (α/β and γ), barley hordein and rye secalin (In some individuals glutenin or glutenin like proteins can play a role) act more as a poison which cause an destructive innate immunity and cellular immunity that flattens the epithelium of affected individuals and causes acute maladsorption. Gluten peptides, particularly when deamidated or transamidated alter the behavior of proteins, most notorious is tissue transglutaminase (tTG) a protein involved in deamidation and tranamidation of the glutamine amide. The response is Mediated by HLA DQ2.5(HLA DQA1*0501:B*0201) and HLA DQ8(HLA DQA1*0301:B1*0302). DQ2.5 is found at high frequency in Sardinia and NW europes including the Irish, Welsh, Cornish, British, Scottish, Norwegian, Swedish, Finnish, Danish, Northern Slavic, Hungarian, Serbian, Yugoslavian, Swiss, Canada, United States and accounts for the overwhelming majority of GSE incidences detected. DQ8 is globally distributed but is at very high frequency in indigeonous northern South Americans, Central Americans, Mexico, Sweden, Finland, Northern Russia, Japan, Korea and Bedoin and is less often associated with GSE, but heterozygotes of DQ2.5/DQ8 such as occur in Scandinavia are at elevated risk relative to homozygotes of either haplotype. GSE is very uncommon in countries where Triticeae is not a primary cultivar, even in susceptible populations, but is on the rise in countries with susceptible populations and growing wheat consumption, such as Japan and Latin America. Aside from Triticeae and DQ2.5 (and/or DQ8), other genetic risk factors are not clear, one CTLA4 gene product shows linkage to celiac disease but 33% more frequent in GSE than in non-GSE. Other risk factors such as chronic infection of GI tract by enterovirus, rotavirus may play a role, but GSE is known to have much higher risk in families than in the general DQ2.5 or DQ8 bearing population indicating complex genetic factors are involved.

Type 1 Diabetes and Triticeae
The incidence of Juvenile Type 1 Diabetes (T1D) is about 1:500 in the U.S. population, and is the result of autoimmune damage to the Islets of Langerhans cells in the pancrease. The level of adult onset T1D plus ambiguous T1D/T2D is unknown. It is unclear the how large a role Triticeae has in T1D which also shows stong linkage to DQ2.5 and DQ8. Childhood (male) Type 1 diabetes increases the risk for GSE and vice versa . A high frequency of diabetes patients have antibodies to the tTG autoantigen, tTG along with increased levels of Gluten specific T-cells in T1D patients. From an evolutionary point of view it is difficult to explain the high association of T1D and DQ2.5 given negatively selective nature of the disease in NW european population given the number of studies suggesting that the "Super B8" haplotypes has been under positive selection, and appears to be the most characteristic HLA type in NW europeans indicating an advanced natural history of the haplotype. A T. aesitivum storage globulin, Glb-1 (locus), was identified that is similar to the hypersensitizing peanut protein Ara h 1 and other known plant hypersensitizing proteins. Antibodies to this protein correlated with levels of lymphocyte infiltration into Islet regions of the pancrease. Enteroviruses may play a role.

Other Autoimmune and Secondary Conditions Linked to Triticeae
These conditions are consider idiopathic because their occurance is unpredictable or have a random association with other diseases (above), particularly GSE. Triticeae glutens are the primary cause of Dermatitis herpetiformis. Cross reactive anti-beef collagen antibodies may explain some DQ8 mediated rheumatoid Arthritis incidences This has resulted because the clinical manifestations of celiac incidences that fall below clinical detection can still promote secondary allergic responses and secondary autoimmune diseases. The frequency in western societies is typically around 1/2 to 1% but the detection rate are typically 10-fold lower. GSE and subclinical GSE are also responsible peripheral neuropathies, depression, chronic fatique syndrome, anemias, gastroesophageoal reflux disease (GERD) that are the indirect consequences of maladsorption of vitamins and essential fatty acids. GSE also elevates the risk for lymphomas and cancers of the intestinal tract; a risk that is irreversible and presses for the need for early detection and treatment.

Exercise Induced Anaphylaxis and Baker's Allergy
Wheat gliadins and potentially oat avenins are associated with another disease, known as Exercise Induced Anaphylaxis (EIA) which is similar to Baker's Allergy as both are mediated by IgE responses. In EIA however the ω-gliadins and similar proteins in other Triticeae genera can be inhaled or enter the blood stream during exercise where they cause acute asthmatic or allergic reaction). . This response to ω-gliadins may stem from a time when the seed grasses of basal Triticeae taxa, as some species still do, produce seeds that get trapped in grazing animals (ear, eyes, nasal cavities) as a potential defense mechanism that also facilitates the seeds spread. One recent study of ω-gliadins demostrated these gliadins are more similar to the bulk of oat avenins than α/β or γ gliadins but, so far, oat avenins have not been linked to EIA.

Links

[1]Pubmed:Triticeae