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From convention to innovation: the role of genetic modification and genome editing in Australian wheat breeding.

Wheat is the most cultivated crop worldwide, and Australia consistently ranks among the top wheat-exporting countries. Although modern technology has expanded the speed and accuracy of conventional breeding, progress is constrained by limited genetic diversity and linkage drag, with new wheat varieties often taking 8-12 years to reach the market. Biotech methods involving the transformation of foreign DNA into genomes [genetic modification (GM)], or editing of native DNA [genome editing (GEd)], provide novel opportunities to efficiently improve traits alongside conventional breeding. In 2020, the world's first GM drought-tolerant bread wheat (HB4) hit the market in Argentina. The USA recently approved HB4 wheat for commercial cultivation, and human consumption of HB4 wheat has been approved by nine countries, including Australia. Currently, 25 countries, Australia included, have deregulated GEd crops in some form, and many other countries have indicated that they will follow suit. As of March 2025, no GM or GEd wheat is commercially grown in Australia. The rate at which private industry integrates GM and GEd into wheat breeding programmes will depend on several factors, including the regulatory consistency governing GM and GEd crops within Australia and among international trading partners, the return on investments relative to deregulation costs including licensing, the level of acceptance amongst growers and consumers, and technical considerations including wheat's amenability to tissue culture. This review contextualizes GM and GEd applications in wheat, often drawing on examples from crop species where biotechnology has been more widely employed, and considers the key stakeholders that will shape the future of GM and GEd wheat in Australia.

GMO↗

Non-starch polysaccharide-degrading enzymes increase the performance of broiler chickens fed wheat of low apparent metabolizable energy.

The effect of a commercial glycanase product (Avizyme TX) on the performance of 4-wk-old broiler chickens fed wheats with low and normal apparent metabolizable energy values was studied. Controls were fed a corn-based diet. Supplementation with the enzyme product significantly (P < 0.01) increased the apparent metabolizable energy of the low metabolizable energy wheat from 12.02 to 14.94 MJ/kg dry matter. The apparent metabolizable energy value of the normal wheat was increased from 14.52 to 14.83 MJ/kg dry matter; this was, however, not significant. Birds fed the low metabolizable energy wheat diet had significantly (P < 0.01) higher digesta viscosity and lower small intestinal starch and protein digestibilities than birds fed the normal wheat diet. Chickens fed the low metabolizable energy wheat tended to grow less than those fed the normal wheat diet. When the low metabolizable energy wheat+enzyme diet was fed, digesta viscosity was significantly (P < 0.01) lower (20.28 vs. 10.36 mPa.s), and small intestinal digestibility coefficient of starch was significantly (P < 0.01) greater (0.584 vs. 0.861) relative to values in birds fed the low metabolizable energy wheat diet alone. Although the protein digestibility coefficient also increased from 0.689 to 0.745, the difference was not significant. Weight gain and feed efficiency of birds fed the low metabolizable energy wheat+enzyme equaled those of controls. The enzyme product significantly (P < 0.01) increased the solubilization of non-starch polysaccharides within the gastrointestinal tract of birds fed both types of wheat diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Wheat sensitization and work-related symptoms in the baking industry are preventable. An epidemiologic study.

A cross-sectional study was conducted among 393 workers from 21 bakeries to study the relationship between wheat allergen exposure and wheat sensitization and work-related allergic symptoms. Exposure to wheat allergens was characterized by a recently developed and validated immunoassay. Specific IgE antibodies against wheat flour and common allergens were measured by immunoassays, and work-related allergic symptoms were registered by questionnaire. A strong and positive association was found between wheat flour allergen exposure and wheat flour sensitization. This relationship was steepest and strongest in atopics. Prevalence ratios for high and medium wheat allergen exposure were 5.2 (95% confidence interval [CI], 1.6-16.2), and 2.7 (0.5-14.5) for atopic workers, and 2.5 (0.8-7.5) and 1.4 (0. 3-6.4) for nonatopics, compared with workers with low wheat allergen exposure. In sensitized bakers those with an elevated allergen exposure had more often work-related symptoms, with prevalence ratios for high and medium wheat allergen exposure of 3.5 (CI 1.6-7. 5) and 2.6 (CI 0.9-7.8), respectively, compared with workers with low wheat allergen exposure. The existence of exposure-sensitization gradients suggests that work-related sensitization risk will be negligible when exposure levels will be reduced to average exposure concentration of 0.2 microgram/m3 wheat allergen or approximately 0.5 mg/m3 inhalable dust during a work shift.

Adult↗

Barley allele-specific amplicons useful for identifying wheat-barley recombinant chromosomes.

Barley (Hordeum vulgare L.) is potentially a new source of genes for wheat (Triticum aestivum L.) improvement. Wheat-barley chromosome recombinant lines provide a means for introgressing barley genes to wheat genome by chromosome engineering, and since these are expected to occur only rarely in special cytogenetic stocks, an efficient selection skill is necessary to identify them. To convert RFLP markers to barley allele-specific PCR markers useful for effective production of wheat-barley recombinant lines, 91 primer sets derived from RFLP clones which were previously mapped to the barley chromosomes were examined for PCR amplification using 'Chinese Spring' wheat, 'Betzes' barley and the wheat-barley chromosome addition lines. The polymorphisms were detected by an agarose gel electrophoresis of the PCR products without digestion with restriction enzymes. Out of 81 primer sets producing polymorphisms between the wheat and barley genomes, 26 amplified barley chromosome-specific DNAs which were confirmed to be located on the same chromosome as the RFLP markers by using the wheat-barley chromosome addition lines. These amplified DNAs represent barley allele-specific amplicons, which distinguish barley alleles from their wheat homoeologous counterparts. The present investigation revealed a higher probability for obtaining allele-specific amplicons from genomic DNA-derived RFLP markers than from cDNA-derived ones. The barley allele-specific amplicons developed in this study, namely, four for chromosome 2H, two for 3H, seven for 4H, eight for 5H, one for 6H and four for 7H, are suitable for identifying 'Chinese Spring' wheat- 'Betzes' barley recombinant chromosomes. However, one out of eight barley allele-specific amplicons on chromosome 5H did not detect a unique barley band in a 'New Golden' barley chromosome 5H addition line of 'Shinchunaga' wheat, indicating there may be a need to reconstruct allele-specific amplicons with different barley cultivars.

Alleles↗

Influence of grazing dormant native range or winter wheat pasture on subsequent finishing cattle performance, carcass characteristics, and ruminal metabolism.

A winter grazing/feedlot performance experiment repeated over 2 yr (Exp. 1) and a metabolism experiment (Exp. 2) were conducted to evaluate effects of grazing dormant native range or irrigated winter wheat pasture on subsequent intake, feedlot performance, carcass characteristics, total-tract digestion of nutrients, and ruminal digesta kinetics in beef cattle. In Exp. 1, 30 (yr 1) or 67 (yr 2) English crossbred steers that had previously grazed native range (n = 38) or winter wheat (n = 59) for approximately 180 d were allotted randomly within previous treatment to feedlot pens (yr 1 native range = three pens [seven steers/pen], winter wheat = two pens [eight steers/pen]; yr 2 native range = three pens [eight steers/pen], winter wheat = four pens [10 or 11 steers/pen]). As expected, winter wheat steers had greater (P < 0.01) ADG while grazing than did native range steers. In contrast, feedlot ADG and gain efficiency were greater (P < 0.02) for native range steers than for winter wheat steers. Hot carcass weight, longissimus muscle area, and marbling score were greater (P < 0.01) for winter wheat steers than for native range steers. In contrast, 12th-rib fat depth (P < 0.64) and yield grade (P < 0.77) did not differ among treatments. In Exp. 2, eight ruminally cannulated steers that had previously grazed winter wheat (n = 4; initial BW = 407 +/- 12 kg) or native range (n = 4; initial BW = 293 +/- 23 kg) were used to determine intake, digesta kinetics, and total-tract digestion while being adapted to a 90% concentrate diet. The adaptation and diets used in Exp. 2 were consistent with those used in Exp. 1 and consisted of 70, 75, 80, and 85% concentrate diets, each fed for 5 d. As was similar for intact steers, restricted growth of cannulated native range steers during the winter grazing phase resulted in greater (P < 0.001) DMI (% of BW) and ADG (P < 0.04) compared with winter wheat steers. In addition, ruminal fill (P < 0.01) and total-tract OM digestibility (P < 0.02) were greater for native range than for winter wheat steers across the adaptation period. Greater digestibility by native range steers early in the finishing period might account for some of the compensatory gain response. Although greater performance was achieved by native range steers in the feedlot, grazing winter wheat before finishing resulted in fewer days on feed, increased hot carcass weight, and improved carcass merit.

Adaptation, Physiological↗

Use of fluorescence genomic in situ hybridization (GISH) to detect the presence of alien chromatin in wheat lines differing in nuclear DNA content.

BACKGROUND: Many times small differences in genome size are reported between or within plant species in which no cytologic confirmation is made. Attempts to repeat these studies have met with limited success. The controversy then becomes whether or not these small differences that were not confirmed cytologically are real. The present study was undertaken to determine if the approximately 1% nuclear variation seen by flow cytometry among wheat lines selected for aluminum response was due to actual chromatin differences. METHODS: The three parental wheat cultivars used in the aluminum selection along with the isolines resulting from the selection were analyzed. One parental line had previously been reported to have alien chromatin substituted for the corresponding wheat homologous chromatin. Genomic in situ hybridization was used to determine the presence or absence of rye chromatin in three cultivars and six near-isolines of wheat. RESULTS: Upon observing metaphase chromosomes of the Century parent and its isolines, two of the chromosomes were observed to be one-half yellow-orange, indicating rye chromatin with the remaining portion of the chromosomes and the other 40 wheat chromosomes having no label indicating wheat chromatin. In the Chisholm parent and its isolines, none of the chromosomes were labeled, indicating the absence of rye chromatin. In addition, none of the third parents' chromosomes had the rye yellow-orange signal. CONCLUSIONS: The wheat lines with the larger DNA contents were observed to have alien DNA present. DNA differences between the normal wheat chromosomes and the substituting alien chromatin were calculated based on total chromosome length. The increase in genome size of the wheat lines containing the alien chromatin appears to be the result of the alien chromatin having approximately 43% more DNA than the wheat chromatin it is replacing. Thus, the small DNA difference previously reported by flow cytometry was demonstrated to be a real DNA variation due to the presence of small fragments of alien chromosomes added to the wheat genome.

Cell Nucleus↗

[Molecular proof of wheat transformed by total DNA of Leymus racemosus].

Four repetitive DNA sequences (pHv7161, pHv7179, pHv7191 and pHv7293) cloned from barley (Hordeum vulgare) genome were used for a molecular hybridization in the genome of Leymus racemosus (donor), Spring wheat 761 (receptor) and the wheat transformed by total DNA of Leymus racemosus (donor) through pollen tube pathway. Our results indicate that some bands are common in Leymus racemosus and the transformed wheat but absent in Spring wheat 761. The HindIII fragments which are common in Leymus racemosus and the transformed wheat have been cloned. The clone of Leymus racemosus was nominated as pLR980. pLR980 contains the homologous sequences to the four repetitive sequences of barley. The pLR980 cloned from Leymus racemosus was used as probe to study Leymus racemosus, Spring wheat 761 and the transformed wheat. This study demonstrate that pLR980 is homologous in both genome of Leymus racemosus and wheat. Common bands absent in the Spring wheat 761 were also showed in Leymus racemosus and the transformed wheat. pLR980 was proved to be associated with the transform of wheat by total DNA of Leymus racemosus through pollen tube pathway. This provides a direct witness to the exogenous DNA introduction.

DNA, Plant↗

[Detection of IgE antibodies to salt-insoluble wheat proteins in sera of patients with atopic dermatitis by ELISA and immunoblotting techniques].

Specific IgE antibodies against salt-insoluble wheat proteins were investigated in sera from 60 patients with atopic dermatitis (AD) positive to wheat specific CAP-RAST. The salt-insoluble wheat protein fraction was prepared from whole protein fraction of wheat flour, which was extracted by PBS containing 6 M urea. IgE antibodies to salt-insoluble proteins were detected in 15 of the sera. IgE-ELISA was applied to these 15 sera, with whole wheat proteins, salt-soluble proteins, and salt-insoluble proteins used as antigens. Wheat specific CAP-RAST values correlated well with the IgE-ELISA titers against salt-soluble proteins (r = 0.918 p < 0.001). On the other hand, IgE-ELISA titers against both the salt-insoluble proteins and the whole wheat proteins correlated least with CAP-RAST values (r = 0.161 and r = 0.113). The inhibition tests indicated that IgE antibodies against salt-insoluble proteins were different from those against salt-soluble ones. Thus, IgE antibodies to salt-insoluble proteins were another antigen target of IgE-mediated allergy manifestation. To determine the molecular weight of antigens reacting with IgE, IgE-immunoblotting was performed. Several polypeptides with molecular weights of 33-45, 84, 90 and 98 KD were detected. However, the antigen patterns of the blots varied depending on the sera used. These findings suggest that salt-insoluble wheat proteins are the major antigens in some wheat-dependent AD, and that IgE detection against salt-insoluble wheat proteins is important for the diagnosis of wheat allergy.

Adolescent↗

Anaphylaxis to wheat beer.

BACKGROUND: Despite its worldwide and abundant consumption, beer has rarely been found to cause anaphylaxis. Barley malt contained in lager beers seems to be an important elicitor. OBJECTIVE: To report the unusual case of severe anaphylaxis following the ingestion of wheat beer. METHODS: A 59-year-old man experienced angioedema, generalized urticaria, and unconsciousness after ingestion of wheat beer. He tolerated lager beer well. For diagnostic evaluation, skin prick tests, oral challenge tests, and identification of specific IgE antibodies were performed. RESULTS: Skin prick test results with standard series of common aeroallergens and food allergens were negative with the exception of a 1 + reaction to wheat flour. The results of skin prick tests with native materials were positive for 2 brands of wheat beer and wheat malt shred but negative for baker's yeast, hops, and a brand of lager beer. Oral challenges with wheat beer or wheat flour elicited urticaria. By CAP-FEIA, specific IgE antibodies to wheat and barley flour but not to hops or baker's yeast were found in serum. Immunoblot analysis revealed that patient's IgE was bound to a protein of approximately 35 kDa in wheat extract. CONCLUSIONS: This is the first report, to our knowledge, on anaphylaxis to beer attributable to wheat allergy.

Anaphylaxis↗

Different profiles of wheat antigens are recognised by patients suffering from coeliac disease and IgE-mediated food allergy.

BACKGROUND: Dietary intake of wheat can cause two distinct immunologically mediated diseases with severe gastrointestinal manifestations, coeliac disease (CD) and IgE-mediated food allergy. The pathomechanisms underlying these diseases are different, but the profile of the target antigens in wheat has not been compared for the two diseases. METHODS: We compared IgA- and IgE-reactive antigens in wheat using sera from patients with coeliac disease (n = 35) and food allergy to wheat (n = 16) by one- and two-dimensional immunoblotting. Furthermore, the IgG subclass (IgG1-IgG4) reactivity to wheat antigens was studied by enzyme-linked immunosorbent assay. RESULTS: IgA antibodies from CD patients and IgE antibodies from allergic patients recognised distinct profiles of wheat antigens. Furthermore, the IgG subclass responses to wheat antigens were different in CD and wheat-allergic patients. CONCLUSION: This study thus demonstrates that wheat contains antigens/epitopes which are preferentially recognised by CD patients, whereas others elicit IgE-mediated food allergy. This finding suggests that the nature of a food antigen may influence the quality of the pathological immune response in the gut and has implications for the diagnosis and therapy of hypersensitivity to wheat.

Adolescent↗

Timing of initial exposure to cereal grains and the risk of wheat allergy.

OBJECTIVE: Early exposure to solid foods in infancy has been associated with the development of allergy. The aim of this study was to examine the association between cereal-grain exposures (wheat, barley, rye, oats) in the infant diet and development of wheat allergy. METHODS: A total of 1612 children were enrolled at birth and followed to the mean age of 4.7 years. Questionnaire data and dietary exposures were obtained at 3, 6, 9, 15, and 24 months and annually thereafter. The main outcome measure was parent report of wheat allergy. Children with celiac disease autoimmunity detected by tissue transglutaminase autoantibodies were excluded. Wheat-specific immunoglobulin E levels on children reported to have wheat allergy were obtained. RESULTS: Sixteen children (1%) reported wheat allergy. Children who were first exposed to cereals after 6 months of age had an increased risk of wheat allergy compared with children first exposed to cereals before 6 months of age (after controlling for confounders including a family history of allergic disorders and history of food allergy before 6 months of age). All 4 children with detectable wheat-specific immunoglobulin E were first exposed to cereal grains after 6 months. A first-degree relative with asthma, eczema, or hives was also independently associated with an increased risk of wheat-allergy development. CONCLUSIONS: Delaying initial exposure to cereal grains until after 6 months may increase the risk of developing wheat allergy. These results do not support delaying introduction of cereal grains for the protection of food allergy.

Age Factors↗

The use of an alternative food source (red clover) as a means of reducing slug pest damage to winter wheat: towards field implementation.

Slugs are major pests of many crops in the UK, including winter wheat, yet current methods of control are often unreliable. The aim of this study was to investigate three issues key to the successful field implementation of a control strategy that uses red clover as an alternative food source to reduce the amount of damage caused to winter wheat by the field slug, Deroceras reticulatum (Müller). A series of three experiments was designed to assess this aim. Firstly, under laboratory conditions, red clover was consumed in greater quantities than wheat, even when wheat was presented as a novel food. Secondly, red clover had no significant effects on the emergence and early growth of wheat in a polytunnel experiment. Both these results are crucial to the successful implementation of a strategy that uses red clover as an alternative food source. Lastly, the results of a field experiment were consistent with the results of the polytunnel experiment, in that red clover did not significantly affect wheat emergence. However, plots in which red clover was left to grow until the time of wheat harvest resulted in significantly lower (43%) wheat yields than plots without red clover. These results suggest that red clover must be removed from the field after the wheat has passed its vulnerable seedling stage. Recommendations for the potential use of red clover as an alternative food source for reducing damage to winter wheat in field conditions are discussed and opportunities for further work are suggested.

Agriculture↗

[Spelt wheat and celiac disease].

Spelt wheat (Triticum spelta L.) has not been investigated for the toxicity on coeliac disease patients until now. Because clinical studies are out of considerations for ethical reasons, spelt wheat and coeliac-active bread wheat (Triticum aestivum L.) were compared by the analysis of N-terminal sequences of alpha-gliadins, which have been proposed to be responsible for the toxic effect. The gliadin fractions of the spelt wheats 'Roquin' and 'Schwabenkorn' and of the bread wheat 'Rektor' were preparatively separated by RP-HPLC and major alpha-gliadin components were then compared by N-terminal sequence analysis. The results did not reveal any significant difference between spelt and bread wheats within the first 25 positions. For the determination of sequences further from the N-terminus, the gliadin fractions of the spelt wheats were hydrolyzed with pepsin and trypsin. The resulting peptides were successively separated by gel permeation chromatography and RP-HPLC. Those peptides derived from the N-terminal part of alpha-gliadins were identified by reference peptides isolated previously from bread wheat [this journal 194: 229 (1992)]. Retention times upon RP-HPLC and amino acid compositions of corresponding peptides confirmed the identity of spelt and bread wheat concerning the N-terminal sequences of alpha-gliadins from position 3 to 56. For these reasons, it can be concluded that spelt wheat is a coeliac-toxic cereal and has to be avoided by coeliac patients.

Amino Acid Sequence↗

Molecular characterization of wheat polyphenol oxidase (PPO).

It is well-established that the enzyme polyphenol oxidase (PPO) is involved in undesirable browning of noodles, chapattis, middle east flat breads and steamed breads. Methods for measuring PPO activity have been developed, and the variation of PPO activity among wheat ( Triticum aestivum L.) cultivars has been well documented. However, there is no report on the identification and characterization of a wheat PPO gene. PCR performed on wheat genomic DNA with oligonucleotide primers designed from conserved copper binding regions of other PPO genes resulted in amplification of a 444-bp DNA fragment. Sequence analysis identified the conserved amino acids of PPO genes indicating that the PCR product was part of the wheat PPO gene. Screening genomic and cDNA libraries using 444- and 760-bp DNA fragments as probes failed to identify a PPO gene based on conserved sequence, even though there were very strong hybridization signals for some isolates. Rapid amplification of cDNA ends (RACE) technique was used as an alternative to obtain the remaining DNA sequences in 5' and 3' directions based on the 444-bp partial wheat PPO gene sequence. With the use of ThermoScript Reverse Transcriptase (which functions at higher temperatures) and Advantage-GC cDNA kit, the complete DNA sequence in the 3' direction was obtained. A similar effort in the 5' direction resulted in amplification of a truncated 414-bp DNA sequence. Overall, 1,509-bp of putative wheat PPO DNA sequence was obtained. Alignment of deduced amino-acid sequences revealed similarity to the other PPO gene sequences, especially in the conserved copper binding regions. Southern-blot analysis performed with four different restriction enzymes revealed two to four DNA fragments, suggesting a limited number of PPO genes in wheat. Wheat genomic DNA restricted with HindIII and hybridized using a 760-bp wheat PPO probe revealed a clear distinction between wheat cultivars with high and low PPO activities. Northern-blot analysis indicated a transcript size of about 2.0-kb. PPO DNA fragment as well as RNA transcript was observed for the durum cultivar Renville which normally has very low PPO activity. Further study is needed to explain the relationship between PPO activity and the presence of PPO gene (s).

Journal Article↗

HMW and LMW glutenin alleles among putative tetraploid and hexaploid European spelt wheat (Triticum spelta L.) progenitors.

The allelic compositions of high- and low-molecular-weight subunits of glutenins (HMW-GS and LMW-GS) among European spelt ( Triticum spelta L.) and related hexaploid and tetraploid Triticum species were investigated by one- and two-dimensional polyacrylamide-gel electrophoresis (PAGE) and capillary electrophoresis (CE). A total of seven novel glutenin alleles (designated A1a*, B1d*, B1g*, B1f*, B1j*, D1a* at Glu-1 and A3h at the Glu-3 loci, respectively) in European spelt wheat were detected by SDS-PAGE, which were confirmed further by employing A-PAGE and CE methods. Particularly, two HMW-GS alleles, Glu-B1d* coding the subunits 6.1 and 22.1, and Glu-B1f* coding the subunits 13 and 22*, were found to occur in European spelt with frequencies of 32.34% and 5.11%, respectively. These two alleles were present in cultivated emmer (Triticum dicoccum), but they were not observed in bread wheat (Triticum aestivum L.). The allele Glu-B1g* coding for 13* and 19* subunits found in spelt wheat was also detected in club wheat (Triticum compactum L.). Additionally, two alleles coding for LMW-GS, Glu-A3h and Glu-B3d, occurred with high frequencies in spelt, club and cultivated emmer wheat, whereas these were not found or present with very low frequencies in bread wheat. Our results strongly support the secondary origin hypothesis, namely European spelt wheat originated from hybridization between cultivated emmer and club wheat. This is also confirmed experimentally by the artificial synthesis of spelt through crossing between old European emmer wheat, T. dicoccum and club wheat, T. compactum.

Alleles↗

Introgression of wheat DNA markers from A, B and D genomes in early generation progeny of Aegilops cylindrica Host x Triticum aestivum L. hybrids.

Introgression from allohexaploid wheat (Triticum aestivum L., AABBDD) to allotetraploid jointed goatgrass (Aegilops cylindrica Host, CCDD) can take place in areas where the two species grow in sympatry and hybridize. Wheat and Ae. cylindrica share the D genome, issued from the common diploid ancestor Aegilops tauschii Coss. It has been proposed that the A and B genome of bread wheat are secure places to insert transgenes to avoid their introgression into Ae. cylindrica because during meiosis in pentaploid hybrids, A and B genome chromosomes form univalents and tend to be eliminated whereas recombination takes place only in D genome chromosomes. Wheat random amplified polymorphic DNA (RAPD) fragments, detected in intergeneric hybrids and introgressed to the first backcross generation with Ae. cylindrica as the recurrent parent and having a euploid Ae. cylindrica chromosome number or one supernumerary chromosome, were assigned to wheat chromosomes using Chinese Spring nulli-tetrasomic wheat lines. Introgressed fragments were not limited to the D genome of wheat, but specific fragments of A and B genomes were also present in the BC1. Their presence indicates that DNA from any of the wheat genomes can introgress into Ae. cylindrica. Successfully located RAPD fragments were then converted into highly specific and easy-to-use sequence characterised amplified regions (SCARs) through sequencing and primer design. Subsequently these markers were used to characterise introgression of wheat DNA into a BC1S1 family. Implications for risk assessment of genetically modified wheat are discussed.

Base Sequence↗

Tracking wheat rust on a continental scale.

The rusts of wheat are important fungal plant pathogens that can be disseminated thousands of kilometers across continents and oceans by wind. Rusts are obligate parasites that interact with resistance genes in wheat in a gene-for-gene manner. New races of rust develop by mutation and selection for virulence against rust resistance genes in wheat. In recent years, new races of wheat leaf rust, wheat stripe rust, and wheat stem rust have been introduced into wheat production areas in different continents. These introductions have complicated efforts to develop wheat cultivars with durable rust resistance and have reduced the number of effective rust-resistance genes that are available for use. The migration patterns of wheat rusts are characterized by identifying their virulence against important rust resistance genes in wheat and by the use of molecular markers.

Australia↗

Alkylresorcinols as markers of whole grain wheat and rye in cereal products.

The alkylresorcinol (AR) content of Swedish wheat grain samples, as well as of cereal ingredients and cereal foods containing wheat and rye, was determined. The average total AR content in Swedish wheat was 412 microg/g (ranging between 227 and 639 microg/g), which is lower than that in Swedish rye analyzed in a previous study. The relative composition of AR homologues was consistent for wheat samples and differed markedly from that of rye. Notably, the ratio of the homologues C17:0/C21:0 was approximately 0.1 in wheat and approximately 1.0 in rye, indicating that it can be used to distinguish between those two cereals. The AR content in cereal foods commonly consumed in Sweden varied widely, from nondetectable levels in white wheat flour and products not containing the outer parts of wheat and/or rye to >900 microg/g in some whole grain rye products. AR content in cereal foods was calculated from their recipes using average AR values for the cereal ingredients determined in this study. As there was a good correlation between calculated and analyzed AR levels in cereal foods (R2 = 0.91), it is possible to estimate the proportion of whole grain wheat and/or rye in a given cereal product on the basis of AR content and C17:0/C21:0 ratio. ARs appear to be good markers of whole grain wheat and rye in foods, and their analysis may be an objective way to identify foods rich in whole grain wheat and/or rye or brans thereof.

Biomarkers↗