Table of Contents

Whole Allergen

g12 Cultivated rye

g12 Cultivated rye Scientific Information

Type:

Whole Allergen

Display Name:

Cultivated rye

Allergen code:

g12

Family:

Poaceae (Gramineae)

Species:

Secale cereale

Route of Exposure:

Inhalation

Latin Name:

Secale cereale

Other Names:

Common rye, Spring rye, Winter rye

WHO/ICD-11 code:

XM8M82

(ICD-11 is currently under implementation by WHO and the ICD-11 codes displayed in the encyclopedia may not yet be available in all countries)

Summary

Globally, grass pollens are a significant cause of IgE-mediated allergy, affecting approximately 40% of all grass allergic patients. Cultivated rye (Secale cereale) is one of the major cereal crops globally. It is used as feed for farm animals. It is widely distributed over the temperate regions of the northern hemisphere and pollinates by the wind. Cultivated rye grass (S. cereale; g12) should not be confused with perennial ryegrass (Lolium perenne; g5); rye, the foodstuff (Secale cereale; f5); and the Wild Rye grass (Elymus tricoides; g70). The pollinating season of cultivated rye varies between May and August, differing according to the geographical location. Its pollens are shed in huge amounts and are considered as a significant triggering factor for acute allergic symptoms like conjunctivitis, allergic rhinitis, and asthma in individuals sensitized to grass pollens. Sensitization to pollens of cereals is widespread. Cultivated rye shows extensive cross-reactivity with the other species of Pooideae family including Timothy grass and perennial ryegrass.

Allergen

Nature

Cultivated rye (Secale cereale) is a diploid annual grass (1) belonging to the sub-family of Pooideae grasses and thus resembles wheat (2). The stem of the plant of cultivated rye is non-brittle and has large seeds (3). The rye plants are usually tall with a height between 18-40 inches. The terminal spike of cultivated rye is long, slender, inclined, and is flattened to a certain degree. It has short awns and bears a 2-flowered spikelet. The leaf blades are flat, varying from 1/16 to 3/8 inches in width. The upper side of the leaves are rough (2).

Pollination of this grass is by the wind. It releases allergenic pollens in huge amounts during the peak flowering time (4, 5). The flowering season differs according to the geographical location. In the eastern regions of the USA, it flowers from May through June/July, while in the Southwest, its flowering takes place between May and August. Nearly 4,200,000 pollen grains are produced from one cultivated rye plant (2).

Cultivated rye is known to be one of the major cereal crops globally. It is used as a feed for farm animals and as a cover crop for making green manure (6). It is used as hay and green fodder (7).

Taxonomy

he cultivated rye (Secale cereale) belongs to the tribe Triticeae and genus Secale (8). This genus has been bio-systematically classified further into 3 species groups namely, S. montanum, S. sylvestre, and S. cereale. The S. cereale contains mostly the annual wild, weedy as well as cultivated rye. This species is said to be evolved from S. montanum. It was consciously or unconsciously selected by the man from the weedy varieties which invaded wheat and barley fields (9).

The current classification of the American Germplasm Resources Information Network indicates four species to this genus that are S. montanum (S. strictum), S. vavilovii, S. sylvestre, and S. cereale. Among all of them, only S. montanum is a perennial plant whereas all others are annual plants (10).

Taxonomic tree of Cultivated rye (11)
Domain	Eukaryota
Kingdom	Plantae
Phylum	Spermatophyta
Subphylum	Spermatophytina
Class	Magnoliopsida
Order	Poales
Family	Poaceae
Genus	Secale
Species	Secale cereale

Tissue

Pollen grains of cultivated rye are large, measuring 53-57 × 38-43 µm. They are ellipsoidal with a single circular pore on the side, towards one end. The border of the pore is wavy, and the diameter is 5.7 µm. The operculum is irregular and small with a diameter of only 2.3 µm (2).

The outer layer of the pollen grain (exine) is sculptured (tectate) like covered with microgranules and with 1.0-1.5 µm thickness. The outer part (sexine) and the inner part (nexine) of the exine are equally thick. The inner layer of the pollen grain (intine) is thicker than the outer layer, measuring up to 5 µm (2). Sec c V, a group 5 allergen is reported as an allergenic molecule from this pollen (12).

Epidemiology

Worldwide distribution

All over the world, grass pollens are an important cause of IgE-mediated allergy. Nearly 40% of all allergic patients are affected by grass pollen allergy (4). Sensitization to pollens of cereals is categorized as the most widespread sensitization (13).

A study in 1998 in Riyadh, Saudi Arabia, reported that cultivated rye was one of the most abundant aeroallergens found in dust samples collected during sandstorms, and are potential triggers of respiratory diseases (14). In Azerbaijan, Iran, 78 (48.6%) of 150 patients (mean age of 30.2 ± 14.7 years) with atopic dermatitis (AD) were found to be sensitized to cultivated rye, of which 39 (53.4%) were females, and 34 (44.1%) were males (15).

Cultivated rye pollen, along with wheat and oat was a major triggering factor for bronchial asthma in 327 allergic patients (aged between 18 to 85 years) in Portugal (16). In a representative sample of 17,641 children and adolescents (0–17 years) across Germany, the German Health Interview and Examination Survey for Children and Adolescents (2003 to 2006) found that the prevalence of allergic sensitization to cultivated rye was 21.2% (CI: 20.0–22.4). In the entire sample, 17% of girls and 25.1% of boys were reported to be allergic to cultivated rye pollen (17). In the Elbasan region, Albania, sensitization to cultivated rye was found in 13.54% (34 out of 251) patients who presented with allergic diseases (18).

Environmental Characteristics

Living environment

Cultivated rye tolerates low temperatures exceptionally well. Though cultivated rye plants adapt extensively, their growth is most favorable in cold climates. It has high frost tolerance. Also, the plant is adaptable to poor soil. It can stand high levels of alumina in soil and drought stress very well. Its growth is preferred in sandy soil or acidic soils; it can also grow on poorly prepared land (10).

It can survive in adverse environmental conditions (1). It can thrive along the roadsides, grasslands open for grazing, and wastelands. It helps control soil erosion and is, therefore sown along highways (2).

Worldwide distribution

The temperate regions of the northern hemisphere have a wide distribution of Pooideae grasses, of which, cultivated rye is an established allergenic species (4). It is the primary cereal crop of temperate regions (7), mainly grown in Europe and North America (2, 7). Some authors believe that cultivated rye is native to Turkey, whereas others argue that it most likely spread from south-western Asia to Russia, and then to Poland and Germany. From here, it is propagated and covered nearly across Europe and ultimately to North America and western parts of South America. It is believed to have been established in China via Turkey; spreading later on to Japan (19).

In Europe, it forms a major cereal crop in the Northern, Central, and Eastern regions (2, 10, 20). The oldest discoveries of cultivated rye occur in central Germany, extending southeast to the Crimea, spreading away from the Caucasus to Asia. It was also found in the mountainous region of Italy (21).

Route of Exposure

Main

Pollens from cultivated rye enter the respiratory system through inhalation (4).

Clinical Relevance

Allergic rhinitis

Pollen from cultivated rye are shed in huge amounts and is considered as a significant triggering factor for allergic rhinitis (AR) in the regions where it is found (2).

Asthma

In individuals sensitized to grass pollens, any contact with the pollen elicits acute inflammatory symptoms like conjunctivitis, asthma, and AR. A study on 673 pediatric patients (between the age of 6 months and 17 years) with allergic disorders was carried out in Moscow, Russia, and found that the specific immunoglobulin E (sIgE) response for cultivated rye was more strongly related to asthma than with upper airway disorders [adjusted Odd’s Ratio (aOR) = 1.14; 95% Confidence Interval (CI) = 0.68;1.91] like rhinosinusitis and AR, and atopic dermatitis (AD) (aOR=2.60; 95% CI = 1.39;4.87) (22).

Atopic dermatitis

Pollen is a significant allergen source in Iran. A study on 31 patients (15 - 32 years) with AD (symptoms like itching, skin dryness, or wool intolerance, aggravated by environmental changes and stress) was carried out in Birjand, Eastern Iran. Cultivated rye was found to be the second leading (29.1%,) cause of allergy after Cypress (35.5%) (23).

Another study on 150 patients with AD who were resistant to treatment, in the northwest of Iran, found that cultivated rye caused allergy in 48.6% of the patients. The patients presented with itching, eczema, dryness of skin, and red rashes as the most common symptoms (15).

Molecular Aspects

Allergenic molecules

To date, only 4 allergens have been identified from S. cereale pollen grains having molecular weights of 28 kDa, 33 kDa, 48 kDa, and 67 kDa (24). Sec c V is a group 5 allergen found to be present in pollens of cultivated rye (12).

Biomarkers of severity

Group 5 allergens are considered as marker allergens for sensitization to grasses in the family Pooideae, including cultivated rye (8).

Cross-reactivity

Cultivated rye shows extensive cross-reactivity with the other species of Pooideae family of grasses (25).

Widespread IgE cross-reactivity was seen between the group 1 grass allergens of Timothy grass (Phleum pratense)), Meadow grass (Poa pratensis), Meadow Fescue (Festuca pratensis), Cocksfoot (Dactylis glomerata), False oatgrass (Arrhenatherum elatius), perennial rye (Lolium perenne), common velvet grass (Holcus lanatus), Redtop grass (Agrostis stolonifera), Sweet Vernal Grass (Anthoxanthum. odoratum) and Cultivated Rye (8, 25). Further, a study has shown cross-reactivity between group 5 allergens of cultivated rye (S. cereale, Sec c V) and perennial ryegrass (Lolium perenne, Lol p 5) (12).

Compiled By

Author: Turacoz Healthcare Solutions

Reviewer: Dr. Christian Fischer

Last reviewed: January 2021

References

Hagenblad J, Oliveira HR, Forsberg NE, Leino MW. Geographical distribution of genetic diversity in Secale landrace and wild accessions. BMC Plant Biol. 2016;16:23.
Weber RW. Cereal rye, Secale cereale. Ann Allergy Asthma Immunol. 2004;92(4):A-6.
Sidhu JS, Ramakrishnan SM, Ali S, Bernardo A, Bai G, Abdullah S, et al. Assessing the genetic diversity and characterizing genomic regions conferring Tan Spot resistance in cultivated rye. PLoS One. 2019;14(3):e0214519.
Gangl K, Niederberger V, Valenta R. Multiple grass mixes as opposed to single grasses for allergen immunotherapy in allergic rhinitis. Clin Exp Allergy. 2013;43(11):1202-16.
Popescu FD. Molecular biomarkers for grass pollen immunotherapy. World J Methodol. 2014;4(1):26-45.
Abdullah S, Sehgal SK, Glover KD, Ali S. Reaction of Global Collection of Rye (Secale cereale L.) to Tan Spot and Pyrenophora tritici-repentis Races in South Dakota. Plant Pathol J. 2017;33(3):229-37.
Bartos J, Paux E, Kofler R, Havrankova M, Kopecky D, Suchankova P, et al. A first survey of the rye (Secale cereale) genome composition through BAC end sequencing of the short arm of chromosome 1R. BMC Plant Biol. 2008;8:95.
Gangl KN, V.; Davies, J. M.; Valenta, R.; Nandy, A. Marker Allergens and Panallergens in Tree and Grass Pollen Allergy. Molecular Allergy Diagnostics Springer; 2017. p. 203-26.
Sencer HAH, J. G. On the origin of cultivated rye. Biological Journal of the Linnean Society. 1980;13(4):299-313.
Skuza L, Szucko I, Filip E, Strzala T. Genetic diversity and relationship between cultivated, weedy and wild rye species as revealed by chloroplast and mitochondrial DNA non-coding regions analysis. PLoS One. 2019;14(2):e0213023.
NCBI. Secale cereale 2020 [cited 2020 Nov 18]. Available from: https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=4550.
van Ree R, Brewczynski PZ, Tan KY, Mulder-Willems HJ, Widjaja P, Stapel SO, et al. Grass pollen immunotherapy induces highly cross-reactive IgG antibodies to group V allergen from different grass species. Allergy. 1995;50(3):281-3.
Damialis A, Konstantinou GN. Cereal pollen sensitisation in pollen allergic patients: to treat or not to treat? Eur Ann Allergy Clin Immunol. 2011;43(2):36-44.
Kwaasi AA, Parhar RS, al-Mohanna FA, Harfi HA, Collison KS, al-Sedairy ST. Aeroallergens and viable microbes in sandstorm dust. Potential triggers of allergic and nonallergic respiratory ailments. Allergy. 1998;53(3):255-65.
Bonyadi MR, D. Hassanzadeh, N. Seyfizadeh and S. Borzoueisileh. Assessment of allergen-specific IgE by immunoblotting method in atopic dermatitis. Eur Ann Allergy Clin Immunol. 2017;49(5):213-9.
Lourenco O, Fonseca AM, Taborda-Barata L. Demographic, laboratory and clinical characterisation of adult portuguese asthmatic patients. Allergol Immunopathol (Madr). 2007;35(5):177-83.
Schmitz R, Ellert U, Kalcklosch M, Dahm S, Thamm M. Patterns of sensitization to inhalant and food allergens - findings from the German Health Interview and Examination Survey for Children and Adolescents. Int Arch Allergy Immunol. 2013;162(3):263-70.
Nikoleta K, Gëzim K, Silvana T. Pollinosis caused by the representatives of Gramineae family. GSC biological and pharmaceutical sciences. 2020;11(2):334-40.
Shang H-YW, Yu-Ming; Wang, Xiao-Rong; Zheng, You-Liang. Genetic diversity and phylogenetic relationships in the rye genus Secale L. (rye) based on Secale cereale microsatellite markers. Genetics and molecular biology. 2006;29(4):685-91.
Targonska M, Bolibok-Bragoszewska H, Rakoczy-Trojanowska M. Assessment of Genetic Diversity in Secale cereale Based on SSR Markers. Plant Mol Biol Report. 2016;34:37-51.
Behre K-E. The history of rye cultivation in Europe. Vegetation History and Archaeobotany. 1992;1:141-56.
Smoldovskaya O, Feyzkhanova G, Voloshin S, Arefieva A, Chubarova A, Pavlushkina L, et al. Allergen-specific IgE and IgG4 patterns among patients with different allergic diseases. World Allergy Organ J. 2018;11(1):35.
Ghaderi R. Prevalence of common allergens among patients with atopic dermatitis in Eastern Iran. MOJ immunology. 2018;6(3).
Montero MT, Alonso E, Sainz T. Allergens from rye pollen (Secale cereale). I. Study of protein release by rye pollen during a 19-hour extraction process. Allergen identification. Allergy. 1992;47(1):22-5.
Johansen N, Weber RW, Ipsen H, Barber D, Broge L, Hejl C. Extensive IgE cross-reactivity towards the Pooideae grasses substantiated for a large number of grass-pollen-sensitized subjects. Int Arch Allergy Immunol. 2009;150(4):325-34.