Understanding the genetics of superior dough performance is essential for improving wheat end-use quality. Here we present a de novo assembly of the genome of JM44, a Chinese wheat cultivar known for its exceptional end-use quality. The JM44 genome achieved reference-level quality (with a quality value of 66.74), depicting a complete picture of complex regions containing gluten genes. Our microsynteny analysis across the Triticum-Aegilops complex showed that high-molecular-weight glutenin subunit loci are highly conserved, while low-molecular-weight glutenin subunits and α-/β-gliadins exhibited greater structural variation. These variable loci appear to have been preferentially selected by humans and contributed substantially to the evolution of wheat quality traits. Moreover, we observed that epistatic interactions between gluten genes are strong in modern cultivars but markedly weaker in landraces, indicating the importance of epistatic selection during modern breeding. Our findings shed light on the genomics and evolution of wheat quality traits, providing valuable guidance for future breeding efforts.

Successful evaluation and screening of salt-tolerant wheat germplasm at different stages are of great importance for breeding resilient crops. In the present study, we tested 30 wheat entries out of 417 American accessions screened in a previous study. Fifteen physiological and biochemical indices were investigated at the seedling stage, and eight agronomic indices at the adult stage. Principal component analysis and correlation analysis found superoxide dismutase activity, soluble protein, and potassium levels to be related to high salt tolerance at the seedling stage. Hierarchical clustering analysis identified seven accessions exhibiting high salt tolerance at both the seedling and adult stages. A Random Forest model was constructed to predict salt-resilient entries at the seedling stage. Transcriptome and quantitative reverse-transcription PCR analyses comparing salt tolerant and sensitive accessions revealed that genes and signaling pathways related to the redox system, MAPK, and plant pathogen interactions contributed to salt resistance. Our results provide basic materials for the breeding of new salt-tolerant wheat varieties, indices to screen for salt-resilient cultivars, and insights into salt-tolerance mechanisms.

Methine sulfoxide reductase (MSR) plays a crucial role in protecting plants from oxidative damages. However, their involvement in copper (Cu) detoxification remains largely uncharacterized. In this study, we identified 17 MSR genes in wheat (Triticum aestivum), 12 MSR genes in Triticum dicoccoides (Td), 6 in Triticum urartu (Tu), and 5 in Aegilops tauschii (Aet). Strong collinearity and conservation were found among orthologs. Three constitutively expressed homoeologs of TaMSRB5 were significantly upregulated in leaves and downregulated in roots of wheat seedlings when exposed to excessive Cu. Overexpression of TaMSRB5 in Arabidopsis significantly enhanced Cu tolerance as evidenced by increased fresh weight and root length in transgenic plants, compared to wild-type (WT, Col-0). Under Cu toxicity, Arabidopsis overexpression lines accumulated similar levels of Cu in their leaves and roots compared with WT. However, they exhibited elevated levels of oxidized glutathione (GSSG), total glutathione (T-GSH), along with Glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) activities. Simultaneously, they showed reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and a lower GSH/ GSSG ratio, indicating enhanced ROS scavenging ability. Consistent with the moderation of oxidative stress, comparative transcriptome analysis revealed that four GST genes were upregulated in transgenic Arabidopsis plants under Cu stress, suggesting the potential relationship between these genes with TaMSRB5 in Cu detoxification. The findings demonstrate the pivotal role of TaMSRB5 in enhancing Cu tolerance in Arabidopsis and provide novel insights into the molecular mechanisms underlying Cu detoxification.

[Objective]The flour color is a crucial index for evaluating wheat quality.Identifying superior allelic variations at loci associated with flour color and clarifying their breeding utilization effects will provide a foundation for molecular marker-assisted breeding of wheat flour color.[Method]Using functional markers,molecular detection was conducted on 12 flour color-related loci in 166 wheat varieties(lines),including the Psy-A1,Pds-B1,Lcye-A1,Lcye-B1,Lox-B1,Ppo-A1,Ppo-B1,Ppo-D1,Pod-A1,Pod-D1,Pod-2D genes,and the 1B/1R translocation.Combined with the phenotypic measurements of flour color parameters(Yellow pigment content(YPC),L* value,a* value,b* value and whiteness),the influence of different allelic variations on flour color were analyzed to comprehensively and systematically evaluate the breeding utilization effects of each locus.[Result]The flour color of the tested materials exhibited a wide variation range.The average value of YPC was 1.18 μg·g-1,with a range of 0.57-2.96 μg·g-1;The average value of L* was 90.29,ranging from 87.12 to 92.16;the average a* value was-0.86,varying between-1.78 and-0.09;the average b* value was 8.83,with a range of 5.21-14.69;and the average whiteness was 86.78,spanning from 81.35 to 90.30.Environment,genotype,and the interaction between genotype and environment all significantly influenced flour color,with genotype exerting the strongest effect on the phenotypic variations.Psy-A1 and 1B/1R translocation significantly affected YPC,L* value,a* value,b* value and whiteness;Lcye-B1 significantly influenced YPC,a* value,b* value and whiteness;Pds-B1 and Lox-B1 significantly impacted L* value,b* value and whiteness;Pod-2D significantly influenced L*value and whiteness;Lcye-A1 significantly affected L* value;Ppo-A1 and Ppo-D1 significantly influenced a* value.These nine loci had substantial impacts on flour color and exhibited great potential for breeding applications.Wheat varieties(lines)containing Psy-A1b,Pds-B1b,Lcye-A1b,Lcye-B1b,Lox-B1a,Ppo-A1b,Ppo-D1a,Pod-2D-GG,Pod-2D-AG and non-1B/1R translocation exhibited high brightness and whiteness flour color.These genotypes were designated as superior alleles,with distribution frequencies of 34.94%,20.48%,97.59%,66.27%,26.38%,50.91%,57.23%,48.80%,15.06%and 51.20%,respectively.As the number of superior alleles increased,the L* value,a* value and whiteness gradually increased,while YPC and b* value gradually decreased.The materials pyramiding 7-8 superior genes exhibited the optimal flour color.There were significant differences in flour color and the allelic variation frequencies of related genes among wheat varieties(lines)from different regions.A total of 22 varieties,such as Zhengyin1,Zimai12 and Wanmai19,carried more than seven superior alleles and could be used as parental materials for breeding wheat varieties with high brightness and whiteness flour.[Conclusion]Psy-A1,Pds-B1,Lcye-A1,Lcye-B1,Lox-B1,Ppo-A1,Ppo-D1,Pod-2D and 1B/1R translocation significantly influence flour color and exhibit strong breeding practicability.Twenty-two wheat varieties,such as Zhengyin1,Zimai12 and Wanmai19,can be used as excellent parents for flour color improvement.

[This corrects the article DOI: 10.3389/fpls.2024.1457437.].

Identifying superior salt-tolerant germplasm and resistance genes is crucial, as wheat (Triticum aestivum L.) seedlings are highly vulnerable to salt stress. Here, using an optimized 150 mM NaCl treatment, we screened 137 Chinese wheat accessions via an organ-specific method. Phenotyping analysis revealed extensive organ-specific divergence, with 48.91% of accessions displaying inconsistent performance between shoot and root length. We then performed comparative transcriptomics on three representative phenotypes at the seedling stage: Gaoyou 2018, representing the salt dual-sensitive group; Huapei 5, representing the salt dual-tolerant group; and Jimai 60, representing the divergent group with higher tolerance in shoots rather than in roots. Analysis of overlapping differentially expressed genes (DEGs) across all three accessions revealed a basal stress response-characterized by induced osmotic defense and suppressed primary growth-exemplifying a classical growth-defense trade-off. Genotype-specific DEG profiling demonstrated that the divergent Jimai 60 maintains its shoot advantage by reinforcing physical barriers and inhibiting apoptosis. Conversely, transcriptomic profiling implies that the systemically tolerant Huapei 5 maintains coordinated shoot and root tolerance at the seedling stage by strongly activating below-ground Na+ homeostasis (efflux and compartmentalization) while simultaneously down-regulating non-essential immune responses to optimize defense energy reallocation. Collectively, our findings provide novel insights into the organ-differentiated salt tolerance of wheat, offering well-characterized elite germplasm and compelling genetic targets for future molecular breeding.

Chinese steamed bread (CSB) is a fundamental dietary staple food in China, but the mechanism of wheat quality properties determining CSB performance remains unclear, which limits the breeding of specific wheat varieties for the production of CSB. The specific volume (SV) is a key parameter for evaluating the CSB performance. In order to clarify the relationship between flour properties and SV of CSB, the parameters reflecting quality properties on flour, dough, and CSB levels of twelve wheat genotypes were determined, and the relationships between these parameters were investigated by correlation analysis and mathematical models. The results showed that SV is not linearly related to the flour or dough properties, whereas a parabolic relationship was observed between SV and lacunarity, B/Lacunarity (filling degree of B-types granules to gluten network), dough storage and loss modulus, which can be preliminarily fitted with polynomial (quadratic) functions. The recommended ranges of these parameters have been tentatively defined accordingly. This study provides valuable insight into the relationship between wheat quality properties and SV of CSB, and provides a foundation for establishing a complete prediction model for CSB performance.

Quinoa has emerged as a premier substitute for wheat, and it has been widely embraced by the food industry. The present study aims to investigate how varying levels of wheat flour substitution with quinoa flour impact dough rheology, protein network structure, starch physicochemical properties, and dough digestibility. With the increasing quinoa flour incorporation level, the protein network was gradually diluted due to the lack of glutenous protein. However, the proportions of small starch granules and long amylopectin chains increased significantly, resulting in an improved viscoelasticity of quinoa-wheat dough. Substituting wheat flour with quinoa flour effectively slowed starch digestion, increasing resistant starch content from 39.37 % to 67.08 %. This substitution promoted the formation of a more stable and well-organized structure, as evidenced by the increased starch resistance to enzymatic hydrolysis during short-range orderliness assessments. Microstructural analysis indicated that the synergy between small starch granules and the protein network enhanced starch molecular orderliness and reduced starch hydrolysis by digestive enzymes, particularly at a 25 % quinoa flour incorporation level. In conclusion, this study provides a foundation for adopting quinoa-and-wheat-based products in the food industry, paving the way for innovative applications.

Apart from starch content, structure is also vital for the eating and nutritional qualities of final products. The study investigated how the starch structure changed during grain filling period using two wheat cultivars with different filling rate. The starch biosynthesis during grain filling was not at uniform speed and most of starches were synthesized before 19 DAF. The starch structure establishment was latter than starch accumulation, but the structure formed at early stage of grain filling was highly related to the final one. The process of starch biosynthesis was closely accompanied by the elongation of amylose chains, increase on branch numbers, B-type granule number and expansion of A-type granule. Further analysis on expression profiles of key genes involved in starch biosynthesis demonstrated that different genes exhibited varying responsiveness to the filling rate, and the resulting imbalance in gene expression may underlie the observed structural differences. Faster filling promoted earlier activation of starch-biosynthesis genes, particularly GBSSI, leading to preferential elongation of amylose chains, higher crystallinity, and more B-type granules. The results will provide new insights to understanding the formation starch structure during grain filling, which may benefit future research on management and breeding.

Broad spectrum resistance genes are desirable in wheat breeding because they confer resistance against multiple pathogens. Kinase fusion proteins confer broad spectrum resistance in wheat. The resistance locus Pm4 encodes a kinase fusion protein that confers resistance to the fungal diseases powdery mildew and wheat blast.

Drought severely threatens wheat production. Under drought conditions, root system architecture (DRSA)-related traits in common wheat significantly affect wheat production. In China, Zhoumai16 is a high-yield winter wheat variety in the Huang-Huai wheat region. It is suitable for high-fertilizer and high-water cultivation and has moderate drought tolerance. DK171 is a newly developed high-yield and stress-tolerant variety, with higher drought tolerance. Thus, identifying genetic loci associated with DRSA-related traits from DK171 and developing available molecular markers are of great importance for enhancing wheat stress tolerance breeding. In this study, DRSA-related traits, including the total root dry weight (DDRW), total root length (DTRL), total root area (DTRA), and the number of root tips (DNRT) under drought stress, were assessed using the hydroponic system in Zhoumai16/DK171 recombinant inbred lines (RIL) population. A total of five quantitative trait loci (QTL) for DRSA-related traits were identified, e.g., QDDRW.daas-1BL, QDTRS.daas-4AL, QDNRT.daas-4DS, QDTRL.daas-3AL, and QDDRW.daas-5D, and explained 6.1% to 18.9% of the phenotypic variances, respectively. Among these, QDTRS.daas-4AL and QDTRL.daas-3AL were consistent with previous reports, whereas the QDDRW.daas-1BL, QDNRT.daas-4DS, and QDDRW.daas-5D are novel. The favorable alleles of QDTRS.daas-4AL and QDNRT.daas-4DS were inherited from Zhoumai16, whereas the favorable alleles for QDDRW.daas-1BL, QDTRL.daas-3AL, and QDDRW.daas-5D were contributed by DK171. Furthermore, five kompetitive allele-specific PCR (KASP) markers, Kasp_1BL_DTRS (QDDRW.daas-1BL), Kasp_3AL_DTRS (QDTRL.daas-3AL), Kasp_4A_DTRS (QDTRA.daas-4A), Kasp_5D_DDRW (QDDRW.daas-5D), and Kasp_4D_DNRT (QDNRT.daas-4D), were developed and validated in a diverse panel with 108 wheat varieties mainly from China. Additionally, eight candidate genes related to plant hormone regulation, ABC transporters, and calcium-dependent lipid-binding domain proteins were identified. This study offers new loci, candidate genes, and available KASP markers for wheat drought tolerance breeding and facilitating progress in developing drought-tolerant wheat cultivars.

Elymus trachycaulus is a perennial species highly resistant to stripe rust and leaf rust, two devastating diseases of wheat worldwide. The wheat-E. trachycaulus 1HtS·1BL Robertsonian translocation line TA5072 carries the leaf rust resistance gene Lr55 and an undesignated stripe rust resistance gene. In this study, we reduced the length of the 1HtS arm in the 1HtS·1BL centric translocation by homoeologous recombination induced by the Chinese Spring ph1b mutation, resulting in a new translocation line, designated TC282. This line was characterized using newly developed fluorescence in situ hybridization (FISH) probes and molecular markers specific to chromosome 1HtS. TC282 was highly resistant to stripe rust and leaf rust, indicating that the reduced segment of 1HtS still carries both rust resistance loci. Additionally, there is no significant difference in the number of spikelets and tillers of TC282 compared with the wheat variety Jimai 22, suggesting that this translocation line can be used for wheat improvement.

The ‘Cuimi’ kumquat is a unique citrus cultivar known for its thin, crisp pulp and sweet, aromatic flavor. In addition to its use in fresh consumption and processing, this variety exhibits certain medicinal properties. This study aims to investigate the genetic diversity of the Huanglongbing (HLB) bacterium across different tissues of the ‘Cuimi’ kumquat, offering a theoretical basis for understanding the HLB epidemic in Dechang County, Sichuan. The research focuses on the absolute quantification of the HLB bacterium in seven specific tissues of the ‘Cuimi’ kumquat, including new leaves, upper phloem of branches, fruit peduncle, pith, fruit axis, old leaves, and lower phloem of branches. Additionally, the types and contents of prophages were identified in these tissues. In the same diseased branch group, Candidatus Liberibacter asiaticus (CLas) exhibited an uneven distribution, with the highest concentration detected in the pith, significantly surpassing levels found in the stem and leaf tissues (new leaves, upper phloem of branches, old leaves, lower phloem of branches). Infected fruit peduncles and pith slices showed noticeable shrinkage and collapse in the phloem. Prophage analysis indicated that multiple types of prophages could be simultaneously detected within the same infected ‘Cuimi’ kumquat branch. New shoot tissues contained both Type 2 and Type 4 prophages, with a relatively higher abundance of Type 4 and a lower abundance of Type 2. The relative abundance of Type 1 prophage in the fruit tissues was generally higher than in other tissues. CLas primarily accumulates in the fruit tissues of the ‘Cuimi’ kumquat, and the situation in Dechang County suggests that individual trees may be infected with multiple prophage strains simultaneously.

Powdery mildew (caused by Blumeria graminis f. sp. tritici) limits grain production and reduces grain quality in wheat. Amblyopyrum muticum (2n = 2x = 14, TT genomes), a wild relative of wheat, carries agronomically valuable traits, including resistance to powdery mildew, that have not been transferred to wheat. Here, a powdery mildew-resistant Chinese Spring-Am. muticum amphiploid was backcrossed to a powdery mildew-susceptible wheat cultivar, and homozygous resistant derivatives with broad-spectrum resistance were selected. Fluorescence in situ hybridization analysis identified chromosome substitution and compensating Robertsonian translocation lines involving chromosome 6T from Am. muticum.

Male-sterile genes and mutants are critical for hybrid seed production in monocotyledonous crops. Lipids are essential structural components of male reproductive organs, such as the anther and pollen. Here, we show that the pollen-preferential gene TaRIP2 is essential for wheat anther development and pollen formation. RT-qPCR analysis revealed TaRIP2 is specifically expressed during the callose and tetrad stages. Using CRISPR/Cas9, we generated TaRIP2 mutants (rip2), which displayed smaller, wilted anthers with defective cuticles and a low proportion of viable pollen grains (~5.7%). Microscopy revealed that the mutant Rip2 microspores had a smaller size, a smooth exine lacking sculptural elements and fewer organelles. RNA-seq identified differentially expressed genes (DEGs) enriched in pathways related to pollen wall formation. KEGG analysis showed these DEGs are involved in cutin, suberine and wax biosynthesis and fatty acid degradation. Fatty acids C16:0, C18:0 and C18:2 were significantly elevated in rip2 anthers. These phenotypes coincided with the downregulation of genes involved in lipid metabolism and anther development. Dual-luciferase and EMSA assays confirmed TaRIP2 is directly regulated by the transcription factor MYB80. Together, our results show TaRIP2 regulates pollen wall formation through the MYB80-control lipid metabolic pathways.

Common wheat (Triticum aestivum L.) is one of the main staple food crops in China. The protein quality of wheat grains directly determines the processing quality and nutritional quality of flour foods. With the growth of the population, the upgrading of the dietary structure, and the transformation of the demand in the food industry, the research on wheat in China has shifted from simply pursuing high yields to a new stage of coordinated improvement of yield, quality, and nutrition. This article systematically reviews the main progress in the research on the quality of wheat grain protein, including the identification of gluten proteins and high-quality subunits, the analysis of the expression regulation of gluten protein genes, the mining of quality-related genes based on multi-omics, the impact of the interaction between proteins and other components on processing characteristics, and the application of biotechnology in the breeding of high-quality wheat. In view of the complex evaluation process and environmental susceptibility of wheat quality traits, as well as the goal of achieving synergistic optimization of nutrition and functionality in protein quality research under the National Whole Grain Action Plan, we examine the challenges and future development prospects of cutting-edge technologies such as marker-assisted selection and gene editing. This review aims to provide theoretical support for the upgrading of the high-quality wheat industry.

Introduction:Powdery mildew (PM) poses an extreme threat to wheat yields and quality.[Methods] In this study, 262 recombinant inbred lines (RILs) of Doumai and Shi 4185 cross were used to map PM resistance genes across four environments. A high-density genetic linkage map of the Doumai/Shi 4185 RIL population was constructed using the wheat Illumina iSelect 90K single-nucleotide polymorphism (SNP) array. Results:In total, four stable quantitative trait loci (QTLs) for PM resistance, QPm.caas-2AS, QPm.caas-4AS, QPm.caas-4BL, and QPm.caas-6BS, were detected and explained 5.6%-15.6% of the phenotypic variances. Doumai contributed all the resistance alleles of QPm.caas-2AS, QPm.caas-4AS, QPm.ca as-4BL, and QPm.caas-6BS. Among these, QPm.caas-4AS and QPm.caas-6BS overlapped with the previously reported loci, whereas QPm.caas-2AS and QPm.caas-4BL are potentially novel. Additionally, six high-confidence genes encoding the NBS-LRR-like resistance protein, disease resistance protein family, and calcium/calmodulin-dependent serine/threonine-kinase were selected as the candidate genes for PM resistance. Three kompetitive allele-specific PCR (KASP) markers, Kasp_PMR_2AS for QPm.caas-2AS, Kasp_PMR_4BL for QPm.caas-4BL, and Kasp_PMR_6BS for QPm.caas-6BS, were developed, and their genetic effects were validated in a natural population including 100 cultivars. Discussion:These findings will offer valuable QTLs and available KASP markers to enhance wheat marker-assisted breeding for PM resistance.

AbstractRye (Secale cereale L.), a close relative of common wheat, represents a valuable genetic resource for enhancing the disease resistance of common wheat. Introducing novel rye-derived genes into wheat can potentially improve disease resistance. In this study, we successfully developed a novel wheat-rye derivative line LCR4 through hybridization between hexaploid triticale line Currency and common wheat cultivar Jimai 22 (JM22). We confirmed that LCR4 was a T2DS·2DL-2RL translocation line via comprehensive molecular cytogenetic analyses, including genomic in situ hybridization, multi-color fluorescence in situ hybridization, molecular marker analysis, and wheat SNP-arrays genotyping. Notably, upon inoculation with Puccinia striiformis f. sp. tritici (Pst) race V26 at the seedling stage and mixed Pst races at the adult stage, LCR4 exhibited robust resistance against stripe rust infection at both stages. Subsequent genetic analysis further elucidated that the translocated 2RL chromosome segment is responsible for this resistance. Consequently, LCR4 harboring elite agronomic traits can be effectively employed in breeding programs against stripe rust.