We assembled a European bread wheat (Triticum aestivum L.) association mapping panel (n = 480) genotyped using a 90,000 feature single nucleotide polymorphism array, with the aim of identifying genetic loci controlling resistance to four fungal diseases: yellow (stripe) rust (YR), brown (leaf) rust (BR), Septoria tritici blotch (ST) and powdery mildew (PM). Simulations showed our panel to have good power to detect genetic loci, with > 50% probability of identifying loci controlling as little as 5% of the variance when heritability was 0.6 or more. Using disease infection data collected across 31 trials undertaken in five European countries, genome-wide association studies (GWAS) identified 34 replicated genetic loci (20 for YR, 12 for BR, two for PM, 0 for ST), with seven loci associated with resistance to two or more diseases. Construction and analysis of eight bi-parental populations enabled two selected genetic loci, yellow rust resistance locus YR_2A010 (chromosome 2A) and YR_6A610 (6A), to be independently cross-validated, along with the development of genetic markers to track resistance alleles at these loci. Notably, the chromosome 2A yellow and brown rust resistance locus corresponds to the 2NvS introgression from the wild wheat species, Aegilops ventricosa. We found evidence of strong selection for 2NvS over recent breeding history, being present in 48% of the most recent cultivars in our panel. Collectively, we define the genetic architectures controlling resistance to major fungal diseases of wheat under European field environments, and provide resources to exploit these for the development of new wheat cultivars with improved disease resistance.

Aims Root research on field-grown crops is hindered by the difficulty of estimating root biomass in soil. Root washing, the current standard method is laborious and expensive. Biochemical methods to quantify root biomass in soil, targeting species-specific DNA, have potential as a more efficient assay. We combined an efficient DNA extraction method, designed specifically to extract DNA from soil, with well-established quantitative PCR methods to estimate the root biomass of 22 wheat varieties grown in field trials over two seasons. We also developed an assay for estimating root biomass for black-grass, a common weed of wheat cultivation. Methods Two robust qPCR assays were developed to estimate the quantity of plant root DNA in soil samples, one specific to wheat and barley, and a second specific to black-grass. Results The DNA qPCR method was comparable, with high correlations, with the results of root washing from soil cores taken from winter wheat field trials. The DNA qPCR assay showed both variety and depth as significant factors in the distribution of root biomass in replicated field trials. Conclusions The results suggest that these DNA qPCR assays are a useful, high-throughput tool for investigating the genetic basis of wheat root biomass distribution in field-grown crops, and the impact of black-grass root systems on crop production.

Many factors are known to influence infection by cereal rusts, including environmental variables such at light, humidity and temperature, the topography of the leaf surface, as well as plant volatiles. However, few studies have aimed to link these factors. Previously, the quantity of light received by wheat seedlings prior to inoculation with Puccinia striiformis f. sp. tritici (Pst) urediniospores was shown to influence yellow rust infection efficiency. In this study we show that germination and the ability of germlings (germinated urediniospores) to enter stomata is enhanced on wheat seedlings subjected to high quantities of light pre-inoculation with Pst urediniospores, while on seedlings exposed to a long dark period germination and infection were compromised. Using headspace collections and gas chromatography-mass spectrometry (GC-MS) analysis thereof, we link this effect of high light quantity to quantitative changes in the profile of volatile organic compounds (VOCs). We show that the VOCs within headspace collections from wheat seedlings exposed to high quantities of light were able to support greater levels of Pst urediniospore germination than the headspace collections from wheat seedlings exposed to a period of dark. In vitro analysis of individual VOCs identified compounds that enhanced Pst urediniospore germination. These VOCs included the sesquiterpene caryophyllene, the monoterpene alpha-pinene, the fatty acid alpha-linolenic acid, the organic alcohols 1-hexanol, 3-hexen-1-ol and 5-hexen-1-ol, the aldehyde cis-3-hexenal and the ester hexyl acetate.

Leaf rust, caused by Puccinia triticina (Pt), is a major disease of wheat and a significant problem for wheat production in Brazil. The Brazilian variety Toropi, released in 1965, has maintained high levels of field, adult plant resistance (APR) to leaf rust across global locations, while microscopic studies have indicated prehaustorial resistance mechanisms. Analyses of gene expression in flag leaves of Toropi, during the early stages of Pt infection, were undertaken to explore the mechanisms behind the APR in Toropi. Differential expression of wheat genes was undertaken, comparing Pt- to mock-inoculated and Pt- to Pt-inoculated time points. Analysis of gene expression indicated a strong response to Pt, which was fully active by 6 h after inoculation (hai). More genes were downregulated than upregulated, particularly at 6 and 12 hai. Gene Ontology enrichment analysis indicated a shutting down of RNA and protein synthesis and an early effect on photosynthesis, with disruption of the electron transfer chain. Analyses of upregulated genes identified genes involved in ATP-binding and protein kinase activity at 6 hai, supporting a rapid metabolic response to Pt infection. A general upregulation of genes involved in transport and metabolism indicated the need to relocate protein and organic-based resources. Alignment of differentially expressed genes with the genomic regions defining four leaf rust APR quantitative trait loci (QTLs) in Toropi identified candidate resistance genes, including a sugar transporter, a receptor kinase and a seven-transmembrane MLO family protein. In addition, 60 Pt genes were identified, 11 being annotated as potential effector proteins.

While considerable breeding effort has focused on increasing the yields of staple crops such as rice and the levels of micronutrients such as iron and zinc, breeding to address the problems of the double-burden of malnutrition has received less attention. Pigmented rice has higher nutritional value and greater health benefits compared to white rice. However, the genetic associations underlying pericarp coloration and accumulation of nutritionally valuable compounds is still poorly understood. Here we report the targeted genetic analysis of 364 rice accessions, assessing the genetic relationship between pericarp coloration (measured using multi-spectral imaging) and a range of phenolic compounds with potential nutritional and health-promoting characteristics. A genome-wide association study resulted in the identification of over 280 single nucleotide polymorphisms (SNPs) associated with the traits of interest. Many of the SNPs were associated with more than one trait, colocalization occurring between nutritional traits, and nutritional and color-related traits. Targeted association analysis identified 67 SNPs, located within 52 candidate genes and associated with 24 traits. Six haplotypes identified within the genes Rc/bHLH17 and OsIPT5 indicated that these genes have an important role in the regulation of a wide range of phenolic compounds, and not only those directly conferring pericarp color. These identified genetic linkages between nutritionally valuable phenolic compounds and pericarp color present not only a valuable resource for the enhancement of the nutritional value of rice but an easy method of selection of suitable genotypes.

Unknown to many, the Philippines is host to a few remaining accessions of the underutilized and understudied cereal foxtail millet (Setaria italica (L.) P. Beauv.). We collected together accessions from different eco-geographical locations within the Philippines, along with a few accessions from Lanyu, Taiwan, to undertake a study of the nutritional value and genetic diversity within accessions of foxtail millet grown in the Philippines. All accessions were field grown in 2022, dry season (DS) at the Institute of Plant Breeding (IPB) Experiment Station, Los Baños, Laguna, Philippines. The accessions were tested for micronutrients, including Zn and Fe, nitrogen as a proxy for protein, β-carotene and a number of phenolic compounds with known nutritional potential. Of the 20 accessions tested, the accessions Bayaras and GB61438 had the highest level of Zn (107.1 mg/kg) and Fe (70.52 mg/kg), respectively, higher than levels found in traditional rice varieties. For β-carotene the highest concentration was found in the accession Balles (∼10µg/g). Twelve phenolic compounds were detected, with catechin, syringic acid, ferulic acid and kaempferol having the highest concentrations and greatest variation between accessions. To assess the genetic diversity of these local foxtail millet accessions, we sequenced a core set of eight accessions to a depth of at least 25-fold. Analysis of the population structure, using genome-wide, high-quality SNPs, showed modest diversity among the accession, with two unadmixed groups. The accessions are monophyletic relative to their earliest common ancestor, with the very light brown accessions emerging earlier than the light brown and reddish-brown varieties. Analysis of Zinc/Iron permease (ZIP) transporters within the foxtail millet reference sequence, var. Yugu1 identified 17 putative ZIP transporters. Variant calling identified SNPs primarily within 3’ and 5’ regions, and introns, indicating variation between foxtail millet accessions within regulatory gene regions rather than in structural proteins. The local foxtail millet accessions found across the Philippines, therefore, represent a potential alternative source of nutrition that would help to address the problems of the double-burden of malnutrition found in the Philippines.

Over half the world population relies on rice for energy, but being a carbohydrate-based crop, it offers limited nutritional benefits. To achieve nutritional security targets in Asia, we must understand the genetic variation in multi-nutritional properties with therapeutic properties and deploy this knowledge to future rice breeding. High throughput, VideometerLAB spectral imaging data has been effective in estimating total anthocyanin content, particularly bound anthocyanin content, using the high prediction power of partial least square (PLS) regression models. Multi-pronged nutritional properties of phenolic compounds and minerals, together with videometerLAB features, were utilized to develop models to classify a collection of black rice varieties into three distinct nutritional quality ideotypes. These derived models for black rice diversity panels were created utilizing videometerLAB data (L, A, B parameters), selected phenolic types (total phenolics, total anthocyanins, and bound flavonoids), and minerals (Molybdenum and Phosphorous). Random forest and artificial neural network models depicted the multi-nutritional features of black rice with 85.35 and 99.9% accuracy, respectively. These prediction algorithms would help rice breeders strategically breed nutritionally valuable genotypes based on simple, high-through-put videometerLAB readings and a small number of nutritional assays.

Additional file 3. Average amounts of 12 phenolic compounds found in 24 teff varieties (μg/g flour) and 7 phenolics not found in significant quantities.

Wheat stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), occurs in all major wheat-growing regions worldwide and poses a constant threat to production. In South Africa, Pst first emerged in 1996 in the Western Cape and has since caused frequent epidemics with three further distinct races (pathotypes) recorded to date. Herein, we undertook detailed genomic-based analyses of four Pst isolates that represent the four dominant Pst races in South Africa recorded between 1996 and 2005. This analysis identified a number of polymorphic genes with features of known effector proteins and provided additional support of the likely stepwise changes in virulence profile of these South African Pst isolates. Next, we carried out comparative genomic-based analyses with 54 additional Pst isolates collected across wheat-growing regions within South Africa between 1996 and 2017 and 58 Pst isolates from East Africa, Pakistan, the UK, and France. This revealed a close genetic relationship between Pst isolates in South Africa and a number from East Africa. Furthermore, we found the South African Pst isolates also grouped closely with isolates identified in the UK in 2013 that were specifically found on triticale, illustrating long-distance transmission of Pst isolates either between these regions or from a common independent source area. This highlights the critical need for close monitoring of Pst. With wheat being the most planted winter cereal crop in South Africa, investment in continuous surveillance is essential to rapidly identify any future introductions that could quickly lead to rust epidemics.

The yellow rust of wheat (caused by Puccinia striiformis f. sp. tritici) is a devastating fungal infection that is responsible for significant wheat yield losses. The main challenge with the detection of this disease is that it can only be visually detected on the leaf surface between 7 and 10 days after infection, and by this point, counter measures such as the use of fungicides are generally less effective. The hypothesis of this study is to develop and use a compact electrochemical-based biosensor for the early detection of P. striiformis, thus enabling fast countermeasures to be taken. The biosensor that was developed consists of three layers. The first layer mimics the wheat leaf surface morphology. The second layer consists of a sucrose/agar mixture that acts as a substrate and contains a wheat-derived terpene volatile organic compound that stimulates the germination and growth of the spores of the yellow rust pathogen P. s. f. sp. tritici. The third layer consists of a nonenzymatic glucose sensor that produces a signal once invertase is produced by P. striiformis, which comes into contact with the second layer, thereby converting sucrose to glucose. The results show the proof that this innovative biosensor can enable the detection of yellow rust spores in 72 h.

Abstract Background: Teff (Eragrostis teff) is a tropical cereal domesticated and grown in the Ethiopian highlands, where it has been a staple food of Ethiopians for many centuries. Food insecurity and nutrient deficiencies are major problems in the country, so breeding for enhanced nutritional traits, such as Zn content, could help to alleviate problems with malnutrition. Results: To understand the breeding potential of nutritional traits in teff a core set of 24 varieties were sequenced and their mineral content, levels of phytate and protein, as well as a number of nutritionally valuable phenolic compounds measured in grain. Significant variation in all these traits was found between varieties. Genome wide sequencing of the 24 teff varieties revealed 3,193,582 unique SNPs and 897,272 unique INDELs relative to the teff reference var. Dabbi. Sequence analysis of two key transporter families involved in the uptake and transport of Zn by the plant led to the identification of 32 Zinc Iron Permease (ZIP) transporters and 14 Heavy Metal Associated (HMA) transporters in teff. Further analysis identified numerous variants, of which 14.6% of EtZIP and 12.4% of EtHMA variants were non-synonymous changes. Analysis of a key enzyme in flavanol synthesis, flavonoid 3’-hydroxylase (F3’H), identified a T-G variant in the teff homologue Et_s3159-0.29-1.mrna1 that was associated with the differences observed in kaempferol glycoside and quercetin glycoside levels. Conclusion: Wide genetic and phenotypic variation was found in 24 Ethiopian teff varieties which would allow for breeding gains in many nutritional traits of importance to human health.

Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici, is a major threat to wheat (Triticum spp.) production worldwide. The objective of this study was to determine the virulence of P. striiformis f. sp. tritici races prevalent in the main wheat growing regions of Kenya, which includes Mt. Kenya, Eastern Kenya, and the Rift Valley (Central, Southern, and Northern Rift). Fifty P. striiformis f. sp. tritici isolates collected from 1970 to 1992 and from 2009 to 2014 were virulence phenotyped with stripe rust differential sets, and 45 isolates were genotyped with sequence characterized amplified region (SCAR) markers to differentiate the isolates and identify aggressive strains PstS1 and PstS2. Virulence corresponding to stripe rust resistance genes Yr1, Yr2, Yr3, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, and Yr27 and the seedling resistance in genotype Avocet S were detected. Ten races were detected in the P. striiformis f. sp. tritici samples obtained from 1970 to 1992, and three additional races were detected from 2009 to 2014, with a single race being detected in both periods. The SCAR markers detected both Pst1 and Pst2 strains in the collection. Increasing P. striiformis f. sp. tritici virulence was found in the Kenyan P. striiformis f. sp. tritici population, and different P. striiformis f. sp. tritici race groups were found to dominate different wheat growing regions. Moreover, recent P. striiformis f. sp. tritici races in East Africa indicated possible migration of some race groups into Kenya from other regions. This study is important in elucidating P. striiformis f. sp. tritici evolution and virulence diversity and useful in breeding wheat cultivars with effective resistance to stripe rust.

Background: Tef (Eragrostis tef) is a tropical cereal domesticated and grown in the Ethiopian highlands, where it has been a staple food of Ethiopians for many centuries. Food insecurity and nutrient deficiencies are major problems in the country, so breeding for enhanced nutritional traits, such as Zn content, could help to alleviate problems with malnutrition. Results: To understand the breeding potential of nutritional traits in tef a core set of 24 varieties were sequenced and their mineral content, levels of phytate and protein, as well as a number of nutritionally valuable phenolic compounds measured in grain. Significant variation in all these traits was found between varieties. Genome wide sequencing of the 24 tef varieties revealed 3,193,582 unique SNPs and 897,272 unique INDELs relative to the tef reference var. Dabbi. Sequence analysis of two key transporter families involved in the uptake and transport of Zn by the plant led to the identification of 32 Zinc Iron Permease (ZIP) transporters and 14 Heavy Metal Associated (HMA) transporters in tef. Further analysis identified numerous variants, of which 14.6% of EtZIP and 12.4% of EtHMA variants were non-synonymous changes. Analysis of a key enzyme in flavanol synthesis, flavonoid 3'-hydroxylase (F3'H), identified a T-G variant in the tef homologue Et_s3159-0.29-1.mrna1 that was associated with the differences observed in kaempferol glycoside and quercetin glycoside levels. Conclusion: Wide genetic and phenotypic variation was found in 24 Ethiopian tef varieties which would allow for breeding gains in many nutritional traits of importance to human health.

Partial resistance to the biotrophic fungal pathogen Claviceps purpurea, causal agent of ergot, has been found that colocates with mutant alleles of the wheat Reduced height (Rht) loci on chromosomes 4B and 4D. These Rht loci represent the wheat orthologs of the Arabidopsis Della genes. To investigate the role of the Rht mutant DELLA proteins in ergot resistance, we assessed C. purpurea infection in wheat near-isogenic lines (NILs) carrying the gibberellic acid (GA)-insensitive semidwarf alleles Rht-B1b and Rht-D1b and the severe dwarf alleles Rht-B1c and Rht-D1c. NILs of the GA-sensitive alleles Rht8 (chromosome 2D) and Rht12 (chromosome 5A) were also included. A general trend toward increased resistance to C. purpurea, with smaller and lighter sclerotia, was observed on the NILs Rht-B1b, Rht-D1b, Rht-B1c, and Rht-D1c, and also on Rht8. Levels of the bioactive GA4 and the auxin indole-3-acetic acid increased after inoculation with C. purpurea, following similar patterns and implicating a potential auxin-mediated induction of GA biosynthesis. In contrast, jasmonic acid (JA) levels fell in the parental lines 'Mercia' and 'Maris Huntsman' after inoculation with C. purpurea, but increased in all the Rht-mutant NILs. Inoculation with C. purpurea did not show any informative changes in the levels of salicylic acid. Our results suggest that GA-mediated degradation of the DELLA proteins and down-regulation of JA-signaling pathways supports infection of wheat by C. purpurea. As these responses are generally associated with necrotrophic fungal pathogens, we propose that the biotroph C. purpurea may have a necrotrophic growth stage.

Abstract Background Leaf rust, caused by the fungal pathogen Puccinia triticina (Pt), is a major constraint to wheat production worldwide. The Brazilian wheat variety Toropi, released in 1965 and commercially cultivated for over 15 years, has maintained a high level of field resistance to leaf rust, while being seedling susceptible to all known Brazilian Pt isolates. Results The adult plant resistance (APR) in Toropi exhibits a prehaustorial phenotype, the pathogens development being halted at appressorial and sub-stomatal vesicle growth stages. A time-course analysis was performed to explore the resistance mechanisms behind the unique APR in Toropi, taking flag leaf samples for RNA sequencing over 24 hours following inoculation with Pt race MDT-MR. An average of 87.8% of paired-end reads aligned to the Chinese Spring IWGSC RefSeq v.1, and 0.53% to the Pt reference transcriptome, release 35. Cross-conditional different expression of wheat genes was undertaken, comparing Pt- to Mock-inoculated, and Pt- to Pt-inoculated timepoints. More genes were downregulated than upregulated, particularly at the early timepoints of 6 and 12 hours after inoculation (hai). GO enrichment analysis indicated a shutting down of RNA and protein synthesis, particularly prevalent from the downregulation of genes involved in ribosome structure and function. There was also an early effect on photosynthesis, with disruption of the electron transfer chain. Analyses of upregulated genes identified genes involved in ATP binding and protein kinase activity at 6 hai, suggesting a rapid metabolic response to Pt inoculation. There was a general upregulation of genes involved in carbohydrate metabolism and oxidoreductase activity (linked to defence through the generation of ROS), and transport of protein/peptides, nitrogen and organic compounds, indicating the possible need to relocate protein-based resources, either for the benefit of the host or the pathogen. Alignment of differentially expressed wheat genes with the genomic regions defining four QTL contributing to the leaf rust APR in Toropi identified a number of potential candidate genes, including a sugar transporter, a receptor kinase and a gene annotated as a seven transmembrane MLO family protein. In addition, 60 Pt genes were identified, six being annotated as potential effector proteins. Expression of four effectors peaked at 6 hai, one at 0 hai and the sixth at 12 hai, all well before the formation of haustoria. Conclusions Analysis of gene expression in the wheat variety Toropi at the point in Pt development at which resistance is effective indicated a strong PTI response, fully active by 6 hai.

Abstract Background Ergot, caused by the fungal pathogen Claviceps purpurea, infects the female flowers of a range of cereal crops, including wheat. To understand the interaction between C. purpurea and hexaploid wheat we undertook an extensive examination of the reprogramming of the wheat transcriptome in response to C. purpurea infection through floral tissues (i.e. the stigma, transmitting and base ovule tissues of the ovary) and over time. Results C. purpurea hyphae were observed to have grown into and down the stigma at 24 h (H) after inoculation. By 48H hyphae had grown through the transmitting tissue into the base, while by 72H hyphae had surrounded the ovule. By 5 days (D) the ovule had been replaced by fungal tissue. Differential gene expression was first observed at 1H in the stigma tissue. Many of the wheat genes differentially transcribed in response to C. purpurea infection were associated with plant hormones and included the ethylene (ET), auxin, cytokinin, gibberellic acid (GA), salicylic acid and jasmonic acid (JA) biosynthetic and signaling pathways. Hormone-associated genes were first detected in the stigma and base tissues at 24H, but not in the transmitting tissue. Genes associated with GA and JA pathways were seen in the stigma at 24H, while JA and ET-associated genes were identified in the base at 24H. In addition, several defence-related genes were differential expressed in response to C. purpurea infection, including antifungal proteins, endocytosis/exocytosis-related proteins, NBS-LRR class proteins, genes involved in programmed cell death, receptor protein kinases and transcription factors. Of particular interest was the identification of differential expression of wheat genes in the base tissue well before the appearance of fungal hyphae, suggesting that a mobile signal, either pathogen or plant-derived, is delivered to the base prior to colonisation. Conclusions Multiple host hormone biosynthesis and signalling pathways were significantly perturbed from an early stage in the wheat – C. purpurea interaction. Differential gene expression at the base of the ovary, ahead of arrival of the pathogen, indicated the potential presence of a long-distance signal modifying host gene expression.

Key message Four QTL for ergot resistance (causal pathogen Claviceps purpurea ) have been identified in the durum wheat cultivar Greenshank. Abstract Claviceps purpurea is a pathogen of grasses that infects flowers, replacing the seed with an ergot sclerotium. Ergot presents a significant problem to rye, barley and wheat, in particular hybrid seed production systems. In addition, there is evidence that the highly toxic alkaloids that accumulate within sclerotia can cross-contaminate otherwise healthy grain. Host resistance to C. purpurea is rare, few resistance loci having been identified. In this study, four ergot resistance loci are located on chromosomes 1B, 2A, 5A and 5B in the durum wheat cv. Greenshank. Ergot resistance was assessed through analysis of phenotypes associated with C. purpurea infection, namely the number of inoculated flowers that produced sclerotia, or resulted in ovary death but no sclerotia, the levels of honeydew produced, total sclerotia weight and average sclerotia weight and size per spike. Ergot testing was undertaken in Canada and the UK. A major effect QTL, QCp.aafc.DH - 2A, was detected in both the Canadian and UK experiments and had a significant effect on honeydew production levels. QCp.aafc.DH - 5B had the biggest influence on total sclerotia weight per spike. QCp.aafc.DH - 1B was only detected in the Canadian experiments and QCp.aafc.DH - 5A in the UK experiment. An RNASeq analysis, undertaken to identify wheat differentially expressed genes associated with different combinations of the four ergot resistance QTL, revealed a disproportionate number of DEGs locating to the QCp.aafc.DH - 1B , QCp.aafc.DH - 2A and QCp.aafc.DH - 5B QTL intervals.

Improving the nutritional quality of rice grains through modulation of bioactive compounds and micronutrients represents an efficient means of addressing nutritional security in societies which depend heavily on rice as a staple food. White rice makes a major contribution to the calorific intake of Asian and African populations, but its nutritional quality is poor compared to that of pigmented (black, purple, red orange, or brown) variants. The compounds responsible for these color variations are the flavonoids anthocyanin and proanthocyanidin, which are known to have nutritional value. The rapid progress made in the technologies underlying genome sequencing, the analysis of gene expression and the acquisition of global 'omics data, genetics of grain pigmentation has created novel opportunities for applying molecular breeding to improve the nutritional value and productivity of pigmented rice. This review provides an update on the nutritional value and health benefits of pigmented rice grain, taking advantage of both indigenous and modern knowledge, while also describing the current approaches taken to deciphering the genetic basis of pigmentation.

Improving the nutritional quality of rice grains through modulation of bioactive compounds and micronutrients represents an efficient means of addressing nutritional security in societies which depend heavily on rice as a staple food. White rice makes a major contribution to the calorific intake of Asian and African populations, but its nutritional quality is poor compared to that of pigmented (black, purple, red orange, or brown) variants. The compounds responsible for these color variations are the flavonoids anthocyanin and proanthocyanidin, which are known to have nutritional value. The rapid progress made in the technologies underlying genome sequencing, the analysis of gene expression and the acquisition of global ‘omics data, genetics of grain pigmentation has created novel opportunities for applying molecular breeding to improve the nutritional value and productivity of pigmented rice. This review provides an update on the nutritional value and health benefits of pigmented rice grain, taking advantage of both indigenous and modern knowledge, while also describing the current approaches taken to deciphering the genetic basis of pigmentation.

Ingestion of gluten proteins (gliadins and glutenins) from wheat, barley and rye can cause coeliac disease (CD) in genetically predisposed individuals. The only remedy is a strict and lifelong gluten-free diet. There is a growing desire for coeliac-safe, whole-grain wheat-based products, as consumption of whole-grain foods reduces the risk of chronic diseases. However, due to the large number of gluten genes and the complexity of the wheat genome, wheat that is coeliac-safe but retains baking quality cannot be produced by conventional breeding alone. CD is triggered by immunogenic epitopes, notably those present in α-, γ-, and ω-gliadins. RNA interference (RNAi) silencing has been used to down-regulate gliadin families. Recently, targeted gene editing using CRISPR/Cas9 has been applied to gliadins. These methods produce offspring with silenced, deleted, and/or edited gliadins, that overall may reduce the exposure of patients to CD epitopes. Here we review methods to efficiently screen and select the lines from gliadin gene editing programs for CD epitopes at the DNA and protein level, for baking quality, and ultimately in clinical trials. The application of gene editing for the production of coeliac-safe wheat is further considered within the context of food production and in view of current national and international regulatory frameworks.