Production of waxy (amylose-free) wheats

Cytology, metabolomics, and proteomics reveal the grain filling process and quality difference of wheat

Comparative proteomics and non-target metabolomics, together with physiological and microstructural analyses of wheat grains (at 15, 20, 25, and 30 days after anthesis) from two different quality wheat varieties (Gaoyou 5766 (strong-gluten) and Zhoumai 18) were performed to illustrate the grain filling material dynamics and to search for quality control genes. The differential expressions of 1541 proteins and 406 metabolites were found. They were mostly engaged in protein metabolism, stress/defense, energy metabolism, and amino acid metabolism, and the metabolism of stored proteins and carbohydrates was the major focus of the latter stages. The core proteins and metabolites in the growth process were identified, and the candidate genes for quality differences were screened. In conclusion, this study offers a molecular explanation for the establishment of wheat quality, and it aids in our understanding of the intricate metabolic network between different qualities of wheat at the filling stage.

Insight into Rheological Properties and Structure of Native Waxy Starches: Cluster Analysis Grouping

Recent interest in the use of waxy starches in food production is due to the possibility of replacing chemically modified starches as texture-forming agents with native starch analogues. However, there is a lack of a coherent research comparing different varieties of commercially available waxy starches with respect to their molecular and functional properties. Therefore, the objective of this study was to compare native waxy starches from potatoes, corn, and rice, with particular attention to rheological characteristics in relation to molecular structure. The investigated potato, corn, and rice starch preparations were characterized by significantly different molecular properties due to both botanical origin of starch and variety. The molecular weights of waxy starches were significantly higher than those of their normal counterparts. This phenomenon was accompanied by a more loose conformation of the waxy starch macromolecule in solution. The presence of amylose confers the ability to coagulate starch sol into gel, resulting in substantial changes in the rheological properties of starch paste, and waxy starch pastes being characterized by more viscous flow and smoother texture. Hierarchical cluster analysis indicated that differences between functional properties are more notable for normal than for waxy preparations, in which potato starch, regardless of its variety, was characterized by the most unique characteristics.

Molecular mechanism for the influence of yam starch multiscale structure on the sensory texture of cooked yam

Yam is a dual-purpose crop as both medicine and food. However, the mechanism controlling the eating quality of yam remains to be elucidated. This study explored the influence of starch multiscale structure on the texture of yam. The results indicated that FS and RC yam have higher hardness and chewiness, while BZ, XM, and PL yam possess waxiness, Fineness, and Stickiness. Statistically, high amylose (AM) can increase hardness, chewiness, and compactness; and average molecular size (Rh) is positively correlated with stickiness, fineness, and waxiness. Specifically, medium- and long-chain amylose (1000 < X ≤ 10,000) and amylopectin (24 < X ≤ 100), particularly medium-chain amylose (1000 < X ≤ 5000) and long-chain amylopectin (24 < X ≤ 36), primarily affect sensory and rheological stickiness. The long chains of amylose form a straight chain interspersed in the crystalline and amorphous regions to support the entire lamellar structure. Higher proportion of amylose long chains, promoting the starch's structural rigidity, which in turn enhanced its hardness-related attributes. Moreover, a higher ratio of long chains within amylopectin results in tightly intertwined adjacent outer chains, forming double helix crystalline zones. This consequently augmenting the texture quality linked to stickiness-related attributes.

Molecular insights on the origin and development of waxy genotypes in major crop plants

Starch is a significant ingredient of the seed endosperm with commercial importance in food and industry. Crop varieties with glutinous (waxy) grain characteristics, i.e. starch with high amylopectin and low amylose, hold longstanding cultural importance in some world regions and unique properties for industrial manufacture. The waxy character in many crop species is regulated by a single gene known as GBSSI (or waxy), which encodes the enzyme Granule Bound Starch Synthase1 with null or reduced activity. Several allelic variants of the waxy gene that contribute to varying levels of amylose content have been reported in different crop plants. Phylogenetic analysis of protein sequences and the genomic DNA encoding GBSSI of major cereals and recently sequenced millets and pseudo-cereals have shown that GBSSI orthologs form distinct clusters, each representing a separate crop lineage. With the rapidly increasing demand for waxy starch in food and non-food applications, conventional crop breeding techniques and modern crop improvement technologies such as gene silencing and genome editing have been deployed to develop new waxy crop cultivars. The advances in research on waxy alleles across different crops have unveiled new possibilities for modifying the synthesis of amylose and amylopectin starch, leading to the potential creation of customized crops in the future. This article presents molecular lines of evidence on the emergence of waxy genes in various crops, including their genesis and evolution, molecular structure, comparative analysis and breeding innovations.

Regulation of Seed Dormancy Genes in Triticeae Species

Wild progenitors of Triticeae crops generally have long dormancy periods. Domesticated crops inherited these longer dormancy alleles from their wild progenitors, which have since been modified and selected during cultivation and utilization by humans. Thus, allelic combinations at different seed dormancy loci are currently represented in Triticeae germplasm preserved in seed repositories and gene banks as accessions and materials of breeding programs. Methods to evaluate seed dormancy are key to explore, analyze, and exploit optimal alleles in dormancy genes. Recent developments in genomics have accelerated the identification and analysis of seed dormancy loci in Triticeae species. Transgenic experiments have been conducted to validate if candidate genes affect seed dormancy and more recently have yielded an array of mutations derived from genome editing for practical applications. The information gathered on these seed dormancy loci provides a deeper knowledge of germplasm diversity and offers strategies to control seed dormancy in breeding programs in Triticeae crops.

Periodic changes in chain lengths distribution parameters of wheat starch during endosperm development

This study analyzed the molecular structure of developing wheat endosperm starch at different stages after anthesis (DAA) using chain length distribution analysis by size exclusion chromatography (SEC) and fluorophore-assisted carbohydrate electrophoresis. Our results revealed periodic changes in the content of both amylose and amylopectin fractions. Specifically, the content of amylose chains with a degree of polymerization (DP) > 100 significantly decreased from 5 to 10 DAA (28% to 21%) and from 15 to 20 DAA (29% to 26%), but increased between 10 and 15 DAA (21% to 29%) and 20 to 25 DAA (30.0% to 33%). Conversely, the content of short amylopectin chains with DP ≤ 32 showed the opposite trend. Interestingly, mRNA expression levels of key starch biosynthesis genes did not exhibit periodic changes. These findings contribute to our understanding of starch biosynthesis and provide important insights for the development of starch-based products.

Genome sequencing reveals the genetic architecture of heterostyly and domestication history of common buckwheat

Common buckwheat, Fagopyrum esculentum, is an orphan crop domesticated in southwest China that exhibits heterostylous self-incompatibility. Here we present chromosome-scale assemblies of a self-compatible F. esculentum accession and a self-compatible wild relative, Fagopyrum homotropicum, together with the resequencing of 104 wild and cultivated F. esculentum accessions. Using these genomic data, we report the roles of transposable elements and whole-genome duplications in the evolution of Fagopyrum. In addition, we show that (1) the breakdown of heterostyly occurs through the disruption of a hemizygous gene jointly regulating the style length and female compatibility and (2) southeast Tibet was involved in common buckwheat domestication. Moreover, we obtained mutants conferring the waxy phenotype for the first time in buckwheat. These findings demonstrate the utility of our F. esculentum assembly as a reference genome and promise to accelerate buckwheat research and breeding.

Pericarp starch metabolism is associated with caryopsis development and endosperm starch accumulation in common wheat

The wheat pericarp is the main component of the caryopsis at the early development stage and ultimately converts into a tissue that covers the mature caryopsis. A large number of starch granules are accumulated in the pericarp, but the production of and the role of starch granules in caryopsis development remain- elusive. In the present study, the relationship between accumulated starch granules and starch metabolism-related genes in wheat pericarp was investigated using paraffin section observations, expression analysis, and mutant analysis. Starch synthesis is initiated before anthesis and is dependent on a sucrose uptake and conversion system similar to that in the endosperm. TaPTST2 is required to initiate the production of pericarp starch granules. Pericarp starch granules gradually disappeared at the filling stage with high expression levels of genes encoding β-amylase, sucrose-phosphate synthase, and sucrose-phosphate phosphatase. As a maternal tissue adjacent to the endosperm and embryo, the pericarp plays a temporary reservoir for excess nutrients delivered into the caryopsis during the early development stage and exported at the filling stage. The pericarp contributes to the development of the endosperm and embryo as well as the accumulation of endosperm starch. The metabolism of pericarp starch may affect the weight of the wheat caryopsis.

Structure and genetic regulation of starch formation in sorghum (Sorghum bicolor (L.) Moench) endosperm: A review

This review focuses on the structure and genetic regulation of starch formation in sorghum (Sorghum bicolor (L.) Moench) endosperm. Sorghum is an important cereal crop that is well suited to grow in regions with high temperatures and limited water resources due to its C4 metabolism. The endosperm of sorghum kernels is a rich source of starch, which is composed of two main components: amylose and amylopectin. The synthesis of starch in sorghum endosperm involves multiple enzymatic reactions, which are regulated by complex genetic and environmental factors. Recent research has identified several genes involved in the regulation of starch synthesis in sorghum endosperm. In addition, the structure and properties of sorghum starch can also be influenced by environmental factors such as temperature, water availability, and soil nutrients. A better understanding of the structure and genetic regulation of starch formation in sorghum endosperm can have important implications for the development of sorghum-based products with improved quality and nutritional value. This review provides a comprehensive summary of the current knowledge on the structure and genetic regulation of starch formation in sorghum endosperm and highlights the potential for future research to further improve our understanding of this important process.

Enrichment of Starch Desserts with the Addition of Apple Juice and Buckwheat Fiber

Buckwheat hulls which are rich in fiber are good ingredients to increase the nutritional value of food products. The aim of this study was to determine the effect of the applied additives in the form of fiber and apple juice on the properties of both potato and corn starch (normal and waxy). In order to characterize the rheological properties of kissel, the pasting characteristic was measured. In the obtained gels, the basic quality parameters were determined. The analysis of texture, color parameters, and also total polyphenol content were determined. Buckwheat hulls, in addition to their high fiber content, are a valuable source of phenolic compounds and can be a great additive in starch desserts. The addition of buckwheat hulls and apple juice improved the nutritional value of the final products but also caused changes in the technological qualities: it increased the initial temperature of potato starch mixtures (by approx. 9 °C); it decreased the viscosity of cold desserts (from 8 to 55%); and increased the hardness of the final product by more than 7 times. In the case of other starches, the recorded changes were much smaller than for potato starch-based products.

Wheat end-use quality: State of art, genetics, genomics-assisted improvement, future challenges, and opportunities

Wheat is the most important source of food, feed, and nutrition for humans and livestock around the world. The expanding population has increasing demands for various wheat products with different quality attributes requiring the development of wheat cultivars that fulfills specific demands of end-users including millers and bakers in the international market. Therefore, wheat breeding programs continually strive to meet these quality standards by screening their improved breeding lines every year. However, the direct measurement of various end-use quality traits such as milling and baking qualities requires a large quantity of grain, traits-specific expensive instruments, time, and an expert workforce which limits the screening process. With the advancement of sequencing technologies, the study of the entire plant genome is possible, and genetic mapping techniques such as quantitative trait locus mapping and genome-wide association studies have enabled researchers to identify loci/genes associated with various end-use quality traits in wheat. Modern breeding techniques such as marker-assisted selection and genomic selection allow the utilization of these genomic resources for the prediction of quality attributes with high accuracy and efficiency which speeds up crop improvement and cultivar development endeavors. In addition, the candidate gene approach through functional as well as comparative genomics has facilitated the translation of the genomic information from several crop species including wild relatives to wheat. This review discusses the various end-use quality traits of wheat, their genetic control mechanisms, the use of genetics and genomics approaches for their improvement, and future challenges and opportunities for wheat breeding.

Comparative transcriptome analyses revealed key genes involved in high amylopectin biosynthesis in wheat

High amylopectin starch is an important modified starch for food processing industries. Despite a thorough understanding of starch biosynthesis pathway, the regulatory mechanism responsible for amylopectin biosynthesis is not well explored. The present study utilized transcriptome sequencing approach to understand the molecular basis of high amylopectin content in three high amylopectin mutant wheat lines ('TAC 6', 'TAC 358', and 'TAC 846') along with parent variety 'C 306'. Differential scanning calorimetry (DSC) of high amylopectin starch identified a high thermal transition temperature and scanning electron microscopy (SEM) revealed more spherical starch granules in mutant lines compared to parent variety. A set of 4455 differentially expressed genes (DEGs) were identified at two-fold compared to the parent variety in high amylopectin wheat mutants. At ten-fold, 279 genes, including two starch branching genes (SBEIIa and SBEIIb), were up-regulated and only 30 genes, including the starch debranching enzyme (DBE), were down-regulated. Among the genes, different isoforms of sucrose non-fermenting-1-related protein kinase-1 (TaSnRK1α2-3B and TaSnRK1α2-3D) and its regulatory subunit, sucrose non-fermenting-4 (SNF-4-2A, SNF-4-2B, and SNF-4-5D), were found to be highly up-regulated. Further, expression of the DEGs related to starch biosynthesis pathway and TaSnRK1α2 and SNF-4 was performed using qRT-PCR. High expression of TaSnRK1α2, SNF-4, and SBEII isoforms suggests their probable role in high amylopectin starch biosynthesis in grain endosperm.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03364-3.

The Potential of Traditional ‘Gaja’ and New Breed Lines of Waxy, Blue and Purple Wheat in Wholemeal Flour Fermentation

The aim of this study was to analyse and compare the acidity, microbiological and colour characteristics, fatty (FA) and amino (AA) acid profiles, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations, and macro- and microelement contents in non-treated (non-fermented) and fermented wholemeal cereal flours of ‘Gaja’ (traditional wheat) and new breed lines DS8888-3-6 (waxy wheat), DS8548-7 (blue wheat) and DS8535-2 (purple wheat). Independent fermentations were undertaken with selected strains of Pediococcus acidilactici, Liquorilactobacillus uvarum and Lactiplantibacillus plantarum. The results revealed that all the wholemeal cereal flours of the analysed wheat varieties are suitable for fermentation with the selected strains because all the fermented samples showed lactic acid bacteria (LAB) viable counts higher than 8.00 log10 CFU/g and desirable low pH values. In most of the cases, fermentation increased the concentration of essential amino acids in the wholemeal cereal samples, and the LAB strain used for fermentation proved to be a significant factor in all the essential amino acid content of wholemeal wheat (p ≤ 0.0001). When comparing the non-fermented samples, the highest GABA content was found in ‘Gaja’ and waxy wheat samples (2.47 µmol/g, on average), and, in all the cases, fermentation significantly increased GABA concentration in the wholemeal cereals. On the other hand, total levels of biogenic amines in wholemeal samples ranged from 22.7 to 416 mg/kg. The wheat variety was a significant factor in all the analysed macro- and microelement contents (p ≤ 0.0001) in the wholemeal cereals. Furthermore, fermentation showed to be a significant factor in most of the FA content of the wholemeal cereal samples. Finally, fermentation can also contribute to improving the biological and functional value of wholemeal wheat flours (by increasing essential amino acids and GABA concentrations); however, safety parameters (e.g., biogenic amines) also should be taken into consideration when optimizing the most appropriate technological parameters.

Genome-Wide Identification of DOF Gene Family and the Mechanism Dissection of SbDof21 Regulating Starch Biosynthesis in Sorghum

Starch is one of the main utilization products of sorghum (Sorghum bicolor L.), the fifth largest cereal crop in the world. Up to now, the regulation mechanism of starch biosynthesis is rarely documented in sorghum. In the present study, we identified 30 genes encoding the C2-C2 zinc finger domain (DOF), with one to three exons in the sorghum genome. The DOF proteins of sorghum were divided into two types according to the results of sequence alignment and evolutionary analysis. Based on gene expressions and co-expression analysis, we identified a regulatory factor, SbDof21, that was located on chromosome 5. SbDof21 contained two exons, encoding a 36.122 kD protein composed of 340 amino acids. SbDof21 co-expressed with 15 genes involved in the sorghum starch biosynthesis pathway, and the Pearson correlation coefficients (PCCs) with 11 genes were greater than 0.9. The results of qRT-PCR assays indicated that SbDof21 is highly expressed in sorghum grains, exhibiting low relative expression levels in the tissues of roots, stems and leaves. SbDOF21 presented as a typical DOF transcription factor (TF) that was localized to the nucleus and possessed transcriptional activation activity. Amino acids at positions 182–231 of SbDOF21 formed an important structure in its activation domain. The results of EMSA showed that SbDOF21 could bind to four tandem repeats of P-Box (TGTAAAG) motifs in vitro, such as its homologous proteins of ZmDOF36, OsPBF and TaPBF. Meanwhile, we also discovered that SbDOF21 could bind and transactivate SbGBSSI, a key gene in sorghum amylose biosynthesis. Collectively, the results of the present study suggest that SbDOF21 acts as an important regulator in sorghum starch biosynthesis, exhibiting potential values for the improvement of starch contents in sorghum.

Pollen staining is a rapid and cost-effective alternative to marker-assisted selection for recessive waxy1 gene governing high amylopectin in maize

Waxy maize is popular for food-, feed- and industrial usage. It possesses a recessive waxy1 (wx1) gene that enhances amylopectin to ~ 95-100%, compared to ~ 70-75% in traditional maize. Marker-assisted selection (MAS) is a preferred approach to converting normal maize into a waxy version. However, it requires specialized expertise, a well-equipped laboratory, and high cost. Here, pollen staining was used as an alternative approach to MAS. BC1F1, BC1F2 and BC2F2 populations in seven genetic backgrounds segregating for the wx1 gene were used. Pollens treated with iodine-potassium iodide showed that wild types (Wx1Wx1) were dark purple, while waxy pollens (wx1wx1) exhibited red colour. Heterozygotes (Wx1wx1) showed a mix of both dark purple and red colour. Staining of endosperm flour also confirmed the same findings. Wx1-based genotyping using phi022 and wx2507F/RG confirmed the same genotypic status. The average amylopectin among genotypes having red coloured pollens was 97.6%, while it was 72.5% among dark purple. Heterozygotes with both dark purple and red pollens had 85.2% amylopectin. Pollen staining showed complete agreement with the genotyping as well as amylopectin contents. Pollen staining saved 81% cost, and 54% time compared to MAS. This is the first report on the utilization of pollen staining for selecting the wx1 allele in segregating populations used for the development of waxy maize hybrids.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01240-1.

Profiling of transcriptional regulators associated with starch biosynthesis in sorghum (Sorghum bicolor L.)

Starch presents as the major component of grain endosperm of sorghum (Sorghum bicolor L.) and other cereals, serving as the main energy supplier for both plants and animals, as well as important industrial raw materials of human beings, and was intensively concerned world widely. However, few documents focused on the pathway and transcriptional regulations of starch biosynthesis in sorghum. Here we presented the RNA-sequencing profiles of 20 sorghum tissues at different developmental stages to dissect key genes associated with sorghum starch biosynthesis and potential transcriptional regulations. A total of 1,708 highly expressed genes were detected, namely, 416 in grains, 736 in inflorescence, 73 in the stalk, 215 in the root, and 268 genes in the leaf. Besides, 27 genes encoded key enzymes associated with starch biosynthesis in sorghum were identified, namely, six for ADP-glucose pyrophosphorylase (AGPase), 10 for starch synthases (SSs), four for both starch-branching enzymes (SBE) and starch-debranching enzymes (DBEs), two for starch phosphorylases (SPs), and one for Brittle-1 (BT1). In addition, 65 transcription factors (TFs) that are highly expressed in endosperm were detected to co-express with 16 out of 27 genes, and 90 cis-elements were possessed by all 27 identified genes. Four NAC TFs were cloned, and the further assay results showed that three of them could in vitro bind to the CACGCAA motif within the promoters of SbBt1 and SbGBSSI, two key genes associated with starch biosynthesis in sorghum, functioning in similar ways that reported in other cereals. These results confirmed that sorghum starch biosynthesis might share the same or similar transcriptional regulations documented in other cereals, and provided informative references for further regulatory mechanism dissection of TFs involved in starch biosynthesis in sorghum.

Maize STARCH SYNTHESIS REGULATING PROTEIN1 positively regulates starch biosynthesis in rice endosperm

Starch is a major component of the endosperm, directly determining grain yield and quality. Although the key enzymes of starch synthesis have been identified and characterised, the regulatory mechanisms remain unclear. In this study, we identified the novel maize STARCH SYNTHESIS REGULATING PROTEIN1 (ZmSSRP1 ), which encodes a typical carbohydrate-binding module 48 (CBM48) protein. Expression analysis revealed that ZmSSRP1 was highly expressed in the maize endosperm, while transient expression in maize leaf protoplasts showed localisation in the plastids, dependent on the N-terminal transit peptide. In addition, overexpression of ZmSSRP1 in rice resulted in a decrease in grain thickness and the 1000-grain weight, as well as affecting the starch content and structure of the rice endosperm. The physicochemical properties of starch in the rice endosperm were also altered compared with the wild-type seeds. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was subsequently performed to determine the expression of starch synthesis-related genes, revealing upregulation of mRNA expression of most genes in the transgenic compared with wild-type lines. Collectively, these findings suggest that ZmSSRP1 acts as a potential regulator of starch synthesis, providing new insight for molecular breeding of high-yielding high-quality maize.

Study of Noodle Quality Based on Protein Properties of Three Wheat Varieties

Waxy wheat offers unique benefits in food processing, including improving the smoothness and performance of the product. However, waxy wheat is not yet commercially available. The protein characteristics, including the protein content, subunit distribution, secondary structure, chemical interactions, and microstructure of the gluten, were explored to realize the full potential of waxy wheat. The results showed that the noodles prepared from waxy wheat had a gentle and glutinous texture compared with GY2018 and YM13. Partial-waxy and waxy wheat had a lower gluten index and glutenin macropolymer (GMP) content than GY2018, indicating a reduced gluten strength. Confocal laser scanning microscopy (CLSM) images showed that the starch granules were not securely attached to the partial-waxy and waxy wheat protein matrix. In addition, the waxy protein chains appeared more elongated and they weakened the protein network. In particular, HMW-GS subunit 2 + 12 may be the essential cause of the weak dough from SKN1. Compared with GY2018 and YM13, SKN1 had the highest number of free sulfhydryl groups. Rather than ionic bonds, hydrophobic interactions increased the gluten network in GY2018, YM13, and SKN1. The weak molecular forces in the gluten will result in a soft noodle texture.

Effects of the different waxy proteins on starch biosynthesis, starch physicochemical properties and Chinese noodle quality in wheat

Noodles are an important food in Asia. Wheat starch is the most important component in Chinese noodles. Loss of the waxy genes leads to lower activity of starch synthesis enzymes and decreased amylose content that further affects starch properties and noodle quality. To study the effects of different waxy (Wx) protein subunits on starch biosynthesis and processing quality, the high-yielding wheat cultivar Jimai 22 was treated with the mutagen ethyl methane sulfonate (EMS) to produce a population of Wx lines and chosen 7 Wx protein combinations. The amylose content increased but swelling power decreased as the number of Wx proteins increased. Both GBSS activity and gene expression were the lowest for the waxy mutant, followed by the mutants with 1 Wx protein. The combinations of these mutant alleles lead to reductions in both RNA expression and protein levels. Noodles made from materials with 2 Wx protein subunits had the highest score, which agreed with peak viscosity. The influence of the Wx-B1 protein on amylose synthesis and noodle quality was the highest, whereas the influence of Wx-A1 protein was the lowest. Mutants with lower amylose content caused by the absence of 1 subunit, especially the Wx-B1 subunit, had superior noodle quality. Additionally, the identified mutant lines can be used as intermediate materials to improve wheat quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-022-01292-x.

A single base change at exon of Wx-A1 caused gene inactivation and starch properties modified in a wheat EMS mutant line

BACKGROUND

Wheat is an essential source of starch. The GBSS or waxy genes are responsible for synthesizing amylose in cereals. The present study identified a novel Wx-A1 null mutant line from an ethyl methanesulfonate (EMS)-mutagenized population of common wheat cv. SM126 using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and agarose gel analyses.

RESULTS

The alignment of the Wx-A1 gene sequences from the mutant and parental SM126 lines showed only one single nucleotide polymorphism causing the appearance of a premature stop codon and Wx-A1 inactivation. The lack of Wx-A1 protein resulted in decreased amylose, total starch and resistant starch. The starch morphology assessment revealed that starch from mutant seeds was more wrinkled, increasing its susceptibility to digestion. Regarding the starch thermodynamic properties, the gelatinization temperature was remarkably reduced in the mutant compared to parental line SM126. The digestibility of native, gelatinized, and retrograded starches was analyzed for mutant M4-627 and the parental SM126 line. In the M4-627 line, rapidly digestible starch contents were increased, whereas resistant starch was decreased in the three types of starch.

CONCLUSION

Waxy protein is essential for starch synthesis. The thermodynamic characteristics were decreased in the Wx-A1 mutant line. The digestibility properties of starch were also affected. Therefore, the partial waxy mutant M3-627 might play a significant role in food improvement. Furthermore, it might also be used to produce high-quality noodles. © 2021 Society of Chemical Industry.

Understanding Wheat Starch Metabolism in Properties, Environmental Stress Condition, and Molecular Approaches for Value-Added Utilization

Wheat starch is one of the most important components in wheat grain and is extensively used as the main source in bread, noodles, and cookies. The wheat endosperm is composed of about 70% starch, so differences in the quality and quantity of starch affect the flour processing characteristics. Investigations on starch composition, structure, morphology, molecular markers, and transformations are providing new and efficient techniques that can improve the quality of bread wheat. Additionally, wheat starch composition and quality are varied due to genetics and environmental factors. Starch is more sensitive to heat and drought stress compared to storage proteins. These stresses also have a great influence on the grain filling period and anthesis, and, consequently, a negative effect on starch synthesis. Sucrose metabolizing and starch synthesis enzymes are suppressed under heat and drought stress during the grain filling period. Therefore, it is important to illustrate starch and sucrose mechanisms during plant responses in the grain filling period. In recent years, most of these quality traits have been investigated through genetic modification studies. This is an attractive approach to improve functional properties in wheat starch. The new information collected from hybrid and transgenic plants is expected to help develop novel starch for understanding wheat starch biosynthesis and commercial use. Wheat transformation research using plant genetic engineering technology is the main purpose of continuously controlling and analyzing the properties of wheat starch. The aim of this paper is to review the structure, biosynthesis mechanism, quality, and response to heat and drought stress of wheat starch. Additionally, molecular markers and transformation studies are reviewed to elucidate starch quality in wheat.

Unearthed New Indel in the Waxy Gene in Glutinous Rice Landraces from Thailand

&lt;b&gt;Background and Objective:&lt;/b&gt; Glutinous rice landraces have played important role in northeastern and northern region of Thailand and the Lao People's Democratic Republic (PDR) by ethnic groups in this area, both as staple food and ritual in rice culture since ancient times. At a present number of these rice, cultivars have decreased and disappeared from villages without considerations and/or explore DNA variation. This study compared target DNA sequences of &lt;i&gt;waxy&lt;/i&gt; genes of a collection of glutinous rice landraces both upland and lowland rice. &lt;b&gt;Materials and Methods:&lt;/b&gt; A collection of 50 glutinous rice landraces was explored DNA variation in the &lt;i&gt;Waxy&lt;/i&gt; gene by re-sequencing DNA of the two segments (i.e., promoter, exon1 and intron1) of a gene. &lt;b&gt;Results:&lt;/b&gt; New InDel of two deletion G at position 11 (GG-) and C at position 15 (CC-) were observed in DNA sequences of the promoter region and 5'untranslalted region of both upland and lowland rice accessions. Further, the (CT)&lt;sub&gt;17&lt;/sub&gt; and (CT)&lt;sub&gt;18&lt;/sub&gt; were two alleles in these glutinous rice landraces from northern and northeastern Thailand. All glutinous rice landraces exhibited a characteristic of low amylose content or glutinous rice: T Single Nucleotide Polymorphisms (SNP) (AGTTATA) in the first intron splice site. &lt;b&gt;Conclusion:&lt;/b&gt; New InDel in DNA sequences of the promoter region of the &lt;i&gt;waxy&lt;/i&gt; gene in glutinous rice landraces was first reported. This implies that it may reflect the status of genetic background in glutinous rice landraces in Thailand.

Molecular characterization of five novel Wx-A1 alleles in common wheat including one silent allele by transposon insertion

Wheat starch is composed of two glucose polymers, amylose and amylopectin. Although several starch synthases are responsible for its synthesis, only the waxy protein is associated with the amylose synthesis. The waxy protein composition of 45 Spanish common wheat landraces from Andalusia (southern Spain) was evaluated. Within these materials, five novel alleles for the Wx-A1 gene were detected. Four of them showed functional proteins (Wx-A1p, Wx-A1q, Wx-A1r and Wx-A1s), although some amino acid changes were found in the mature protein sequence. However, one of them (Wx-A1t) exhibited loss of the Wx-A1 protein, and its base sequence contained one large insert (1,073 bp) in the tenth exon, that interrupted the ORF of the Wx-A1 gene. This insert exhibited the characteristics of a Class II transposon of the Mutator superfamily, which had not been described previously, and has been named Baetica. The conservation of such inserts could be related to their low effect on vital properties of the plants, as occurs with most of the genes associated with technological quality. In conclusion, the evaluation of old wheat landraces showed that, in addition to their use as alternative crops, these materials could be a useful source of interesting genes in wheat quality improvement.

Longer Bread Shelf-Life and Improved Noodle-Making Properties Imparted by a Novel Wheat Genotype Are Stable in Different Genetic Backgrounds

A recently developed wheat variety, known as 5-5 wheat, which has inactive GBSSI-B1, GBSSI-D1, SSIIa-B1, and SSIIa-D1 isozymes, accumulates a novel type of starch, affecting bread texture and leading to reduction in bread staling. These properties are potentially useful for commercial bakery products; thus, the 5-5 genotype represents a new resource for wheat breeding. In this study, the 5-5 alleles were backcrossed into the hard wheat variety "Minaminokaori" and the soft wheat variety "Shirogane-Komugi", which are both leading Japanese wheat varieties. In comparison to their parental varieties, the two 5-5 near-isogenic lines (NILs) showed a decrease in amylose levels, an increase in the proportion of short chains of amylopectin, a lower gelatinization temperature and enthalpy change, a higher peak viscosity and breakdown viscosity as measured by a Rapid Visco Analyzer, a reduced retrogradation rate, and an increase in grain hardness. Importantly, the 5-5 NILs also showed lower bread crumb firmness and reduced hardening after storage for 2 days at either 20 °C or 7 °C. Considering the results obtained here along with those from the original line, it is clear that the 5-5 genotype can generate specific changes in starch characteristics and staling regardless of its genetic background. Thus, we renamed the 5-5 wheat lines "Slow Staling" (SS) wheat. As expected, our results indicated that the hard wheat SS NIL was more suitable for bread-making. On the other hand, we found that white salted noodle made with the SS NIL of the soft wheat variety had a relatively shorter cooking time, a softer texture, and a reduction in textural changes during storage, all of which are potentially useful for noodle manufacturers.

Identification and molecular characterization of mutant line deficiency in three waxy proteins of common wheat (Triticum aestivum L.)

Starch is the main component of wheat (Triticum aestivum L.) grain and a key factor in determining wheat processing quality. The Wx gene is the gene responsible for amylose synthesis. An ethyl methanesulfonate (EMS) mutagenized population was generated using common wheat cv. Gao 8901, a popular and high-quality cultivar in China. A waxy mutant (Wx-null) was isolated by screening M3 seeds with KI-I₂ staining of endosperm starch. No obvious waxy proteins in Wx-null line were detected using Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). DNA sequencing revealed three SNPs and a 3-bp InDel in the first exon, and a 16-bp InDel at the junction region of the first Wx-A1 intron from the Wx-null line. Six SNPs were identified in Wx-B1 gene of Wx-null line compared to the wild-type Gao 8901, including four missense mutations. One nonsense mutation was found at position 857 in the fourth exon, which resulted in a premature stop codon. Expression levels of Wx genes were dramatically reduced in the Wx-null line. There were no detectable differences in granule size and morphology between Wx-null and wild-type, but the Wx-null line contained more B-type starch granules. The amylose content of the Wx-null line (0.22%) was remarkably lower compared to the wild-type Gao 8901 (24.71%). Total starch is also lower in the Wx-null line. The Wx-null line may provide a potential waxy material with high agronomic performance in wheat breeding programs.

Triple null mutations in starch synthase SSIIa gene homoeologs lead to high amylose and resistant starch in hexaploid wheat

BACKGROUND

Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety 'Jagger' and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type.

RESULTS

Knock-out mutations in SSIIa in the three genomes of wheat variety 'Jagger' were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~ 118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition.

CONCLUSIONS

Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.

Re-examination of the APETALA2/Ethylene-Responsive Factor Gene Family in Barley (Hordeum vulgare L.) Indicates a Role in the Regulation of Starch Synthesis

The APETALA2/Ethylene-Responsive factor (AP2/ERF) gene family is a large plant-specific transcription factor family, which plays important roles in regulating plant growth and development. A role in starch synthesis is among the multiple functions of this family of transcription factors. Barley (Hordeum vulgare L.) is one of the most important cereals for starch production. However, there are limited data on the contribution of AP2 transcription factors in barley. In this study, we used the recently published barley genome database (Morex) to identify 185 genes of the HvAP2/ERF family. Compared with previous work, we identified 64 new genes in the HvAP2/ERF gene family and corrected some previously misannotated and duplicated genes. After phylogenetic analysis, HvAP2/ERF genes were classified into four subfamilies and 18 subgroups. Expression profiling showed different patterns of spatial and temporal expression for HvAP2/ERF genes. Most of the 12 HvAP2/ERF genes analyzed using quantitative reverse transcription-polymerase chain reaction had similar expression patterns when compared with those of starch synthase genes in barley, except for HvAP2-18 and HvERF-73. HvAP2-18 is homologous to OsRSR1, which negatively regulates the synthesis of rice starch. Luciferase reporter gene, and yeast one-hybrid assays showed that HvAP2-18 bound the promoter of AGP-S and SBE1 in vitro. Thus, HvAP2-18 might be an interesting candidate gene to further explore the mechanisms involved in the regulation of starch synthesis in barley.

Interplay Between the N-Terminal Domains of Arabidopsis Starch Synthase 3 Determines the Interaction of the Enzyme With the Starch Granule

The elongation of the linear chains of starch is undertaken by starch synthases. class 3 of starch synthase (SS3) has a specific feature: a long N-terminal region containing starch binding domains (SBDs). In this work, we analyze in vivo the contribution of these domains to the localization pattern of the enzyme. For this purpose, we divided the N-terminal region of Arabidopsis SS3 in three domains: D1, D2, and D3 (each of which contains an SBD and a coiled-coil site). Our analyses indicate that the N-terminal region is sufficient to determine the same localization pattern observed with the full-length protein. D2 binds tightly the polypeptide to the polymer and it is necessary the contribution of D1 and D3 to avoid the polypeptide to be trapped in the growing polymer. The localization pattern of Arabidopsis SS3 appears to be the result of the counterbalanced action of the different domains present in its N-terminal region.

Amylose in starch: towards an understanding of biosynthesis, structure and function

Starch granules are composed of two distinct glucose polymers - amylose and amylopectin. Amylose constitutes 5-35% of most natural starches and has a major influence over starch properties in foods. Its synthesis and storage occurs within the semicrystalline amylopectin matrix of starch granules, this poses a great challenge for biochemical and structural analyses. However, the last two decades have seen vast progress in understanding amylose synthesis, including new insights into the action of GRANULE BOUND STARCH SYNTHASE (GBSS), the major glucosyltransferase that synthesises amylose, and the discovery of PROTEIN TARGETING TO STARCH1 (PTST1) that targets GBSS to starch granules. Advances in analytical techniques have resolved the fine structure of amylose, raising new questions on how structure is determined during biosynthesis. Furthermore, the discovery of wild plants that do not produce amylose revives a long-standing question of why starch granules contain amylose, rather than amylopectin alone. Overall, these findings contribute towards a full understanding of amylose biosynthesis, structure and function that will be essential for future approaches to improve starch quality in crops.

Starch Metabolism in Wheat: Gene Variation and Association Analysis Reveal Additive Effects on Kernel Weight

Kernel weight is a key determinant of yield in wheat (Triticum aestivum L.). Starch consists of amylose and amylopectin and is the major constituent of mature grain. Therefore, starch metabolism in the endosperm during grain filling can influence kernel weight. In this study, we sequenced 87 genes involved in starch metabolism from 300 wheat accessions and detected 8,141 polymorphic sites. We also characterized yield-related traits across different years in these accessions. Although the starch contents fluctuated, thousand kernel weight (TKW) showed little variation. Polymorphisms in six genes were significantly associated with TKW. These genes were located on chromosomes 2A, 2B, 4A, and 7A; none were associated with starch content or amylose content. Variations of 15 genes on chromosomes 1A and 7A formed haplotype blocks in 26 accessions. Notably, accessions with higher TKWs had more of the favorable haplotypes. We thus conclude that these haplotypes contribute additive effects to TKW.

Genome-Edited Triple-Recessive Mutation Alters Seed Dormancy in Wheat

Common wheat has three sets of sub-genomes, making mutations difficult to observe, especially for traits controlled by recessive genes. Here, we produced hexaploid wheat lines with loss of function of homeoalleles of Qsd1, which controls seed dormancy in barley, by Agrobacterium-mediated CRISPR/Cas9. Of the eight transformed wheat events produced, three independent events carrying multiple mutations in wheat Qsd1 homeoalleles were obtained. Notably, one line had mutations in every homeoallele. We crossed this plant with wild-type cultivar Fielder to generate a transgene-free triple-recessive mutant, as revealed by Mendelian segregation. The mutant showed a significantly longer seed dormancy period than wild-type, which may result in reduced pre-harvest sprouting of grains on spikes. PCR, southern blotting, and whole-genome shotgun sequencing revealed that this segregant lacked transgenes in its genomic sequence. This technique serves as a model for trait improvement in wheat, particularly for genetically recessive traits, based on locus information from diploid barley.

Amylose and amylopectin functionality during storage of bread prepared from flour of wheat containing unique starches

Bread crumb firming is largely determined by the properties of gluten and starch, and the transformations they undergo during bread making and storage. Amylose (AM) and amylopectin (AP) functionality in fresh and stored bread was investigated with NMR relaxometry. Bread was prepared from flours containing normal and atypical starches, e.g., flour from wheat line 5-5, with or without the inclusion of Bacillus stearothermophilus α-amylase. Initial crumb firmness increased with higher levels of AM or shorter AM chains. Both less extended AM and gluten networks and too rigid AM networks led to low crumb resilience. AP retrogradation during storage increased when crumb contained more AP or longer AP branch chains. Shorter AP branch chains, which were present at higher levels in 5-5 than in regular bread, were less prone to retrogradation, thereby limiting gluten network dehydration due to gluten to starch moisture migration. Correspondingly, crumb firming in 5-5 bread was restricted.

Multi-Locus GWAS of Quality Traits in Bread Wheat: Mining More Candidate Genes and Possible Regulatory Network

In wheat breeding, improved quality traits, including grain quality and dough rheological properties, have long been a critical goal. To understand the genetic basis of key quality traits of wheat, two single-locus and five multi-locus GWAS models were performed for six grain quality traits and three dough rheological properties based on 19, 254 SNPs in 267 bread wheat accessions. As a result, 299 quantitative trait nucleotides (QTNs) within 105 regions were identified to be associated with these quality traits in four environments. Of which, 40 core QTN regions were stably detected in at least three environments, 19 of which were novel. Compared with the previous studies, these novel QTN regions explained smaller phenotypic variation, which verified the advantages of the multi-locus GWAS models in detecting important small effect QTNs associated with complex traits. After characterization of the function and expression in-depth, 67 core candidate genes involved in protein/sugar synthesis, histone modification and the regulation of transcription factor were observed to be associated with the formation of grain quality, which showed that multi-level regulations influenced wheat grain quality. Finally, a preliminary network of gene regulation that may affect wheat quality formation was inferred. This study verified the power and reliability of multi-locus GWAS methods in wheat quality trait research, and increased the understanding of wheat quality formation mechanisms. The detected QTN regions and candidate genes in this study could be further used for gene cloning and marker-assisted selection in high-quality breeding of bread wheat.

Starch and Glycogen Analyses: Methods and Techniques

For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included.

Novel intron length polymorphic (ILP) markers from starch biosynthesis genes reveal genetic relationships in Indian wheat varieties and related species

Introns experience lesser selection pressure, thus are liable for higher polymorphism. Intron Length Polymorphic (ILP) markers designed from exon-flanking introns exploits this polymorphic potential and have been proved to be a robust co-dominant marker in eukaryotes. Wheat is among the most consumed cereal crop by majority of the word population. It is a rich source of calories in the form of stored starch. In the current study, starch biosynthesis genes were mined for development of ILP markers and their subsequent utilization for genetic characterization of popular Indian wheat varieties and transferability to wild relatives. Sixty-one markers generated 122 alleles and showed 77-88.5% transferability (mean PIC: 0.36) to the related species. A subset of markers showed clear genetic distinctions (Avg. genetic dissimilarity = 0.42) among Indian wheat varieties, signifying the importance of novel ILPs. 'Kenphad25' showed maximum genetic dissimilarity with 'K 8962' (0.82), while maximum genetic similarity was observed between 'Safed Lerma' and 'RAJ 4037' (0.1). This is the first report of ILP markers in wheat and will be a useful genomic resource for future germplasm conservation and molecular breeding studies.

Development and identification of three functional markers associated with starch content in lotus (Nelumbo nucifera)

It have been significantly demonstrated that Hexokinase (HXK), Granule-bound starch synthase (GBSS) and ADP-glucose pyrophosphorylase (AGPase) are three critical enzymes in the starch biosynthetic pathway and are related to starch (amylose, amylopectin and total starch) content in lotus. It is important to develop functional markers in marker-assisted selection of lotus breeding. So far there have been few reports about lotus functional markers. In this study, based on insertion-deletions (INDELs) and single-nucleotide polymorphisms (SNPs), we developed three functional markers, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1. FMHXK-E1 was developed based on polymorphisms of two haplotypes of NnHXK. 26 lotus cultivars that the 320-bp fragment presented in NnHXK had a lower content of amylose and a higher content of amylopectin. FMGBSS-I8 was developed based on polymorphisms of two haplotypes of NnGBSS. The group containing 32 lotus cultivars with the 210-bp fragment had less amylose content and more amylopectin content. FMAGPL-I1 was developed based on polymorphisms of two haplotypes of NnAGPL (ADP-glucose pyrophosphorylase large subunit gene). The group containing 40 lotus cultivars with the 362-bp fragment had less amylopectin, total starch content and more amylose content. According to the study, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1 are closely related to lotus starch content. It could be provided research basis for molecular assisted selection of lotus starch content improve breeding efficiency.

A maize NAC transcription factor, ZmNAC34, negatively regulates starch synthesis in rice

ZmNAC34 might function as an important regulator of starch synthesis by decreasing total starch accumulation and soluble sugar content and increasing amylose fractions. Starch is a major component in endosperm and directly influences seed yield and the cooking quality of cereal grains. Starch is synthesized through a series of complex biological processes. Nevertheless, the mechanism by which starch biosynthesis is regulated in maize is still unclear. In this study, ZmNAC34, a NAC transcription factor related to starch synthesis, was screened based on transcriptome sequencing data. Subsequent qRT-PCR analysis showed that ZmNAC34 is specifically expressed in maize endosperm. Transactivation and subcellular localization assays revealed that ZmNAC34 possesses two characteristics of transcription factors: nuclear localization and transactivation activity. Overexpression of ZmNAC34 in rice decreased total starch accumulation and soluble sugar content, while increased amylose fractions. Meanwhile, the transgenic seeds exhibited alterant starch structure and abnormal morphology. In addition, compared with WT seeds, most of the 17 starch biosynthesis-related genes were significantly upregulated in transgenic seeds from 6 to 15 DAP (day after pollination). These data reveal that ZmNAC34 might function as an important regulator of starch synthesis, thus providing a new perspective on controlling seed yield and quality.

A single-base change at a splice site in Wx-A1 caused incorrect RNA splicing and gene inactivation in a wheat EMS mutant line

An EMS-induced single-base mutation at a splice site caused abnormal RNA splicing and resulted in the gene inactivation and the lack of Wx-A1 protein in a wheat EMS mutant line. An EMS-mutagenized population was generated using common wheat cv. SM126 consisting of 10,600 M2 plants. One Wx-A1 null mutant was identified through analyses of 390 grains produced from 130 M2 plants using electrophoresis analyses. The Wx-A1 sequences of parental line SM126 and M2-31 mutant were determined as 2781 bp, and there was only one SNP mutation between them. The SNP was a mutation from G to A at nucleotide sequence position 2168 bp (G2168A) downstream of the start codon which was located at the splicing site within the eighth intron. All 52 cDNA transcripts were found to be incorrectly spliced and can be summarized as five types of variations. The deletion of the exon and the exclusion of intron were structural features in abnormal splicing RNA. Together with the prediction of potential splice regulatory motifs, the mutation G2168A happened within the 5' splice site of the eighth intron and destroyed the splice donor site from GU to AU, which may have brought about a barrier against correct RNA splice, and generated abnormal mRNA, which was the mechanism of the inactivation of Wx-A1 in M2-31. The lack of Wx-A1 has resulted in changes in starch properties in the M2-31 mutant, with the reduction in amylose and starch contents. The increased grains hardness was observed in M2-31, which may be related to the lower expression level of Pinb-D1 gene. As the waxy wheat foods have a lot of advantages, the null waxy genes will be widely applied in breeding waxy wheat for varied amylose contents.

Amylose-Free ("waxy") Wheat Colonization by Fusarium spp. and Response to Fusarium Head Blight

Hexaploid waxy wheat (Triticum aestivum L.) has null mutations in Wx genes and grain lacking amylose with increased digestibility and usability for specialty foods. The waxy cultivar Mattern is susceptible to Fusarium head blight (FHB) caused by Fusarium graminearum species complex, which produces the mycotoxin deoxynivalenol (DON). In experiment 1, conducted during low natural FHB, grain from waxy breeding lines, Mattern, and wild-type breeding lines and cultivars were assessed for Fusarium infection and DON concentration. Nine Fusarium species and species complexes were detected from internally infected (disinfested) grain; F. graminearum infections were not different between waxy and wild-type. Surface- and internally infected grain (nondisinfested) had greater numbers of Fusarium isolates across waxy versus wild-type, but F. graminearum-like infections were similar; however, DON levels were higher in waxy. In experiment 2, conducted during a timely epidemic, disease severity, Fusarium-damaged kernels (FDK), and DON were assessed for waxy breeding lines, Mattern, and wild-type cultivars. Disease severity and FDK were not significantly different from wild-type, but DON was higher in waxy than wild-type lines. Across both experiments, waxy breeding lines, Plant Introductions 677876 and 677877, responded similarly to FHB as moderately resistant wild-type cultivar Overland, showing promise for breeding advanced waxy cultivars with reduced FHB susceptibility.