Fusarium Head Blight Resistance Research Articles

Characterization of the wheat-tetraploid Thinopyrum elongatum 7E(7D) substitution line with Fusarium head blight resistance

BackgroundFusarium head blight (FHB), a devastating disease of wheat production, is predominantly elicited by Fusarium graminearum (Fg). The tetraploid Thinopyrum elongatum is a tertiary gene resource of common wheat that possesses high affinity and displays high resistance traits against multiple biotic and abiotic stress. We aim to employ and utilize the novel FHB resistance resources from the wild germplasm of common wheat for breeding.ResultsDurum wheat-tetraploid Th. elongatum amphiploid 8801 was hybridized with common wheat cultivars SM482 and SM51, and the F5 generation was generated. We conducted cytogenetically in situ hybridization (ISH) technologies to select and confirm a genetically stable 7E(7D) substitution line K17-1069-5, which showed FHB expansion resistance in both field and greenhouse infection experiments and displayed no significant disadvantage in agronomic traits compared to their common wheat parents in the field. The F2 segregation populations (K17-1069-5 × SM830) showed that the 7E chromosome conferred dominant FHB resistance with dosage effect. We developed 19 SSR molecular markers specific to chromosome 7E, which could be conducted for genetic mapping and large breeding populations marker-assisted selection (MAS) during selection procedures in the future. We isolated a novel Fhb7 allele from the tetraploid Th. elongatum chromosome 7E (Chr7E) using homology-based cloning, which was designated as TTE7E-Fhb7.ConclusionsIn summary, our study developed a novel wheat-tetraploid Thinopyrum elongatum 7E(7D) K17-1069-5 substitution line which contains stable FHB resistance.

Verification of the Fusarium‐Increasing Properties of the Dominant Dwarfing Gene Ddw1 in triticale (×Triticosecale)

ABSTRACTDwarfing genes that are considerably reducing plant height are used in many cereals. In triticale, the rye‐derived dominant dwarfing gene Ddw1 was introgressed in commercial varieties. It has already been shown that this gene increases Fusarium head blight (FHB) susceptibility in one segregating population. We aimed for verifying this effect in the genetically unrelated doubled haploid (DH) population Cando (Ddw1) × Tritikon (ddw1), with 182 progenies in an experiment with artificial inoculation across six location–year combinations (environments). Linkage mapping was performed with DArTseq markers. The progenies significantly (p < 0.001) varied for FHB severity, plant height and heading stage with high entry‐mean heritabilities (0.85–0.98). The population showed a bimodal distribution for plant height. A significant QTL on chromosome 5RL was found for all three traits explaining 38%, 62% and 43% of the genotypic variation for FHB severity, plant height and heading stage, respectively, and most likely representing Ddw1. This gene increased FHB severity by 5.6 percentage points, delayed heading by 2.7 EC stages and reduced plant height by 29.6 cm on average. To use this gene in practical triticale breeding, the genetic background must be enriched with FHB resistance QTL to counterbalance the negative effect of Ddw1 either by introgression of major FHB QTL from exotic sources or by genomic selection within the adapted gene pool.

High-throughput identification of fusarium head blight resistance in wheat varieties using field robot-assisted imaging and deep learning techniques

Fusarium head blight (FHB) has attracted much attention in food science and agriculture for its threat to wheat yields and food safety, due to the production of mycotoxins like deoxynivalenol (DON). Breeding of wheat varieties with improved FHB resistance is essential for controlling this disease. However, identifying resistance in different materials during variety selection remains time-consuming and labor-intensive. Therefore, this paper proposed a high-throughput method for the evaluation of FHB disease symptoms. It enabled the semiautomatic acquisition of images of individual wheat ears in a field environment with the aid of a field robot. The images obtained were semantically segmented to get a single wheat ear, from which the infected spikelets (ISs) were extracted, and then the disease degree was calculated. The results showed that the accuracy value of the individual wheat ear using DeepLabV3+ reached 0.996. The accuracy value of ISs was over 0.98. The mean Accuracy of this method for identifying the resistance of varieties was 0.967, and the precision of a single severity grade reached 0.980. The results indicate that the proposed method enables the acquisition and extraction of disease phenotype and rapid identification of resistance to FHB. The study also provides a reference for accurately identifying phenotypes of wheat ears in other field environments and for selecting and breeding other fungal-toxin-resistant varieties.

ATP-binding cassette transporter TaABCG2 contributes to Fusarium head blight resistance by mediating salicylic acid transport in wheat.

ATP-binding cassette (ABC) transporters hydrolyse ATP to transport various substrates. Previous studies have shown that ABC transporters are responsible for transporting plant hormones and heavy metals, thus contributing to plant immunity. Herein, we identified a wheat G-type ABC transporter, TaABCG2-5B, that responds to salicylic acid (SA) treatment and is induced by Fusarium graminearum, the primary pathogen causing Fusarium head blight (FHB). The loss-of-function mutation of TaABCG2-5B (ΔTaabcg2-5B) reduced SA accumulation and increased susceptibility to F. graminearum. Conversely, overexpression of TaABCG2-5B (OE-TaABCG2-5B) exerted the opposite effect. Quantification of intracellular SA in ΔTaabcg2-5B and OE-TaABCG2-5B protoplasts revealed that TaABCG2-5B acts as an importer, facilitating the transport of SA into the cytoplasm. This role was further confirmed by Cd2+ absorption experiments in wheat roots, indicating that TaABCG2-5B also participates in Cd2+ transport. Thus, TaABCG2-5B acts as an importer and is crucial for transporting multiple substrates. Notably, the homologous gene TaABCG2-5A also facilitated Cd2+ uptake in wheat roots but did not significantly influence SA accumulation or FHB resistance. Therefore, TaABCG2 could be a valuable target for enhancing wheat tolerance to Cd2+ and improving FHB resistance.

Early and late responses to Fusarium Head blight in durum wheat: Focus on phenylpropanoid biosynthetic pathway

Durum wheat is among the cereal crops most susceptible to Fusarium Head Blight (FHB), a fungal disease that can lead to significant yield losses. Despite this, only limited research efforts have been directed towards understanding FHB resistance in durum wheat. Wheat grains naturally contain phenolic compounds, and anthocyanins are particularly present in the so-called pigmented wheat genotypes, such as purple pericarp ones. In this study the effects of the biotic stress caused by Fusarium graminearum infection on phenylpropanoid biosynthetic pathway in durum wheat spikes were explored, considering three genotypes with different susceptibility (including a purple pericarp genotype), and two time points (an early stage time point: 2 days post infection, and a late stage time point: 21 days post infection). At early infection stage, the F. graminearum infection triggered upregulation of all the considered genes involved in the phenylpropanoid pathway in the resistant genotype, while, in the purple pericarp genotype, the infection caused an increase in quercetin accumulation in the soluble fraction of spike extract. At late infection stage, the infection caused (in all the genotypes) a degradation of secondary cell wall and the release of the hydroxycinnamic acids esterified with arabinoxylans (ferulic acid and p-coumaric acid) and lignin-derived monomers (vanillic acid). Furthermore, chalcone synthase gene (CHS) and the transcription factor Ppm1 (Purple pericarp MYB 1) were boosted in the pigmented genotype due to infection at late infection stage. These findings contribute to the understanding of host-pathogen interactions for future breeding programs focused on improving FHB resistance in durum wheat varieties, with a particular focus on pigmented genotypes.

QTL analysis of native Fusarium head blight and deoxynivalenol resistance in ‘D8006W’/’Superior’, soft white winter wheat population

BackgroundFusarium head blight (FHB), caused by Fusarium graminearum, is a major disease of wheat in North America. FHB infection causes fusarium damaged kernels (FDKs), accumulation of deoxynivalenol (DON) in the grain, and a reduction in quality and grain yield. Inheritance of FHB resistance is complex and involves multiple genes. The objective of this research was to identify QTL associated with native FHB and DON resistance in a ‘D8006W’/’Superior’, soft white winter wheat population.ResultsPhenotyping was conducted in replicated FHB field disease nurseries across multiple environments and included assessments of morphological and FHB related traits. Parental lines had moderate FHB resistance, however, the population showed transgressive segregation. A 1913.2 cM linkage map for the population was developed with SNP markers from the wheat 90 K Infinium iSelect SNP array. QTL analysis detected major FHB resistance QTL on chromosomes 2D, 4B, 5A, and 7A across multiple environments, with resistance from both parents. Trait specific unique QTL were detected on chromosomes 1A (visual traits), 5D (FDK), 6B (FDK and DON), and 7D (DON). The plant height and days to anthesis QTL on chromosome 2D coincided with Ppd-D1 and were linked with FHB traits. The plant height QTL on chromosome 4B was also linked with FHB traits; however, the Rht-B1 locus did not segregate in the population.ConclusionsThis study identified several QTL, including on chromosome 2D linked with Ppd-D1, for FHB resistance in a native winter wheat germplasm.

Responses of Wheat (Triticum aestivum) Constitutively Expressing Four Different Monolignol Biosynthetic Genes to Fusarium Head Blight Caused by Fusarium graminearum.

The Fusarium head blight (FHB) pathogen Fusarium graminearum produces the trichothecene mycotoxin deoxynivalenol and reduces wheat yield and grain quality. Spring wheat (Triticum aestivum) genotype CB037 was transformed with constitutive expression (CE) constructs containing sorghum (Sorghum bicolor) genes encoding monolignol biosynthetic enzymes caffeoyl coenzyme A (CoA) 3-O-methyltransferase (SbCCoAOMT), 4-coumarate-CoA ligase (Sb4CL), or coumaroyl shikimate 3-hydroxylase (SbC3'H) or monolignol pathway transcriptional activator SbMyb60. Spring wheats were screened for type I (resistance to initial infection, using spray inoculations) and type II (resistance to spread within the spike, using single-floret inoculations) resistances in the field (spray) and greenhouse (spray and single floret). Following field inoculations, disease index, percentage of Fusarium-damaged kernels (FDK), and deoxynivalenol measurements of CE plants were similar to or greater than those of CB037. For greenhouse inoculations, the area under the disease progress curve (AUDPC) and FDK were determined. Following screens, focus was placed on two each of SbC3'H and SbCCoAOMT CE lines because of trends toward a decreased AUDPC and FDK observed following single-floret inoculations. These four lines were as susceptible as CB037 following spray inoculations. However, single-floret inoculations showed that these CE lines had a significantly reduced AUDPC (P < 0.01) and FDK (P ≤ 0.02) compared with CB037, indicating improved type II resistance. None of these CE lines had increased acid detergent lignin compared with CB037, indicating that lignin concentration may not be a major factor in FHB resistance. The SbC3'H and SbCCoAOMT CE lines are valuable for investigating phenylpropanoid-based resistance to FHB.

Assessment of Fusarium Head Blight Resistance Genes in Domestic Wheat Varieties

Assessment of Fusarium Head Blight Resistance Genes in Domestic Wheat Varieties

Using Transcriptomics to Determine the Mechanism for the Resistance to Fusarium Head Blight of a Wheat-Th. elongatum Translocation Line.

Fusarium head blight (FHB), caused by the Fusarium graminearum species complex, is a destructive disease in wheat worldwide. The lack of FHB-resistant germplasm is a barrier in wheat breeding for resistance to FHB. Thinopyrum elongatum is an important relative that has been successfully used for the genetic improvement of wheat. In this study, a translocation line, YNM158, with the YM158 genetic background carrying a fragment of diploid Th. elongatum 7EL chromosome created using 60Co-γ radiation, showed high resistance to FHB under both field and greenhouse conditions. Transcriptome analysis confirmed that the horizontal transfer gene, encoding glutathione S-transferase (GST), is an important contributor to FHB resistance in the pathogen infection stage, whereas the 7EL chromosome fragment carries other genes regulated by F. graminearum during the colonization stage. Introgression of the 7EL fragment affected the expression of wheat genes that were enriched in resistance pathways, including the phosphatidylinositol signaling system, protein processing in the endoplasmic reticulum, plant-pathogen interaction, and the mitogen-activated protein kinase (MAPK) signaling pathway at different stages after F. graminearium infection. This study provides a novel germplasm for wheat resistance to FHB and new insights into the molecular mechanisms of wheat resistance to FHB.

Genomic regions influencing the hyperspectral phenome of deoxynivalenol infected wheat

The quantitative nature of fusarium head blight (FHB) resistance requires further exploration of the wheat genome to identify regions conferring resistance. In this study, we explored the application of hyperspectral imaging of Fusarium-infected wheat kernels and identified regions of the wheat genome contributing significantly to the accumulation of Deoxynivalenol (DON) mycotoxin. Strong correlations were identified between hyperspectral reflectance values for 204 wavebands in the 397–673 nm range and DON mycotoxin. Dimensionality reduction using principal components was performed for all 204 wavebands and 38 sliding windows across the range of wavebands. The first principal component (PC1) of all 204 wavebands explained 70% of the total variation in waveband reflectance values and was highly correlated with DON mycotoxin. PC1 was used as a phenotype in a genome wide association study and a large effect QTL on chromosome 2D was identified for PC1 of all wavebands as well as nearly all 38 sliding windows. The allele contributing variation in PC1 values also led to a substantial reduction in DON. The 2D polymorphism affecting DON levels localized to the exon of TraesCS2D02G524600 which is upregulated in wheat spike and rachis tissues during FHB infection. This work demonstrates the value of hyperspectral imaging as a correlated trait for investigating the genetic basis of resistance and developing wheat varieties with enhanced resistance to FHB.

Fusarium graminearum effector FgEC1 targets wheat TaGF14b protein to suppress TaRBOHD-mediated ROS production and promote infection.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating disease of wheat globally. However, the molecular mechanisms underlying the interactions between F. graminearum and wheat remain unclear. Here, we identified a secreted effector protein, FgEC1, that is induced during wheat infection and is required for F. graminearum virulence. FgEC1 suppressed flg22- and chitin-induced callose deposition and reactive oxygen species (ROS) burst in Nicotiana benthamiana. FgEC1 directly interacts with TaGF14b, which is upregulated in wheat heads during F. graminearum infection. Overexpression of TaGF14b increases FHB resistance in wheat without compromising yield. TaGF14b interacts with NADPH oxidase respiratory burst oxidase homolog D (TaRBOHD) and protects it against degradation by the 26S proteasome. FgEC1 inhibited the interaction of TaGF14b with TaRBOHD and promoted TaRBOHD degradation, thereby reducing TaRBOHD-mediated ROS production. Our findings reveal a novel pathogenic mechanism in which a fungal pathogen acts via an effector to reduce TaRBOHD-mediated ROS production.

Molecular Investigations to Improve Fusarium Head Blight Resistance in Wheat: An Update Focusing on Multi-Omics Approaches.

Fusarium head blight (FHB) is mainly caused by Fusarium graminearum (Fg) and is a very widespread disease throughout the world, leading to severe damage to wheat with losses in both grain yield and quality. FHB also leads to mycotoxin contamination in the infected grains, being toxic to humans and animals. In spite of the continuous advancements to elucidate more and more aspects of FHB host resistance, to date, our knowledge about the molecular mechanisms underlying wheat defense response to this pathogen is not comprehensive, most likely due to the complex wheat-Fg interaction. Recently, due to climate changes, such as high temperature and heavy rainfall, FHB has become more frequent and severe worldwide, making it even more urgent to completely understand wheat defense mechanisms. In this review, after a brief description of the first wheat immune response to Fg, we discuss, for each FHB resistance type, from Type I to Type V resistances, the main molecular mechanisms involved, the major quantitative trait loci (QTLs) and candidate genes found. The focus is on multi-omics research helping discover crucial molecular pathways for each resistance type. Finally, according to the emerging examined studies and results, a wheat response model to Fg attack, showing the major interactions in the different FHB resistance types, is proposed. The aim is to establish a useful reference point for the researchers in the field interested to adopt an interdisciplinary omics approach.

Identification and transferring of a new Fusarium head blight resistance gene FhbRc2 from Roegneria ciliaris 3ScL chromosome arm into common wheat

Fusarium head blight (FHB) threatens wheat production worldwide. Utilization of FHB resistant varieties is the most effective solution for disease control. Owing to the limited sources of FHB resistance, mining of novel resistance genes is crucial. Here, we report an FHB resistance gene from a wild wheat relative species, Roegneria ciliaris and developed FHB resistant germplasm containing this gene. Wheat-R. ciliaris disomic addition line DA3Sc showed enhanced type II FHB resistance compared to its sister line 3Sc-Null without chromosome 3Sc, indicating that the resistance was contributed by the addition of 3Sc. The resistance gene on 3Sc was validated using F2 and F2:3 populations derived from the cross between DA3Sc and susceptible Aikang 58 (a susceptible cultivar), demonstrating that the lines with 3Sc had significantly enhanced FHB resistance compared to the individuals without 3Sc. This was the second resistance gene identified in R. ciliaris, designated FhbRc2. To transfer FhbRc2 to common wheat, we produced a double-monosomic chromosome population by crossing DA3Sc with the Chinese Spring nulli-tetrasomic line N3DT3B. Eight alien chromosome lines containing 3Sc were identified using genomic/fluorescence in situ hybridization and 3Sc-specific marker analysis. Only the lines carrying the long arm of 3Sc conferred FHB resistance, further locating FhbRc2 on 3ScL. A compensating wheat-R. ciliaris Robertsonian translocation line T3DS·3ScL harboring FhbRc2 is developed and provides a potential genetic resource in wheat breeding for enhanced FHB resistance.

Cytogenetic identification and molecular mapping for the wheat-Thinopyrum ponticum introgression line with resistance to Fusarium head blight.

Xinong 511, a new wheat-Thinopyrum ponticum variety with excellent fusarium head blight resistance, the QTLs were mapped to the wheat chromosomes 5B and 7A with named QFhb.nwafu-5B and QFhb.nwafu-7A, respectively. Novel Fusarium head blight (FHB) resistance germplasms and genes are valuable for wheat improvement and breeding efforts. Thinopyrum ponticum, a wild relative of common wheat, is a valuable germplasm of disease resistance for wheat improvement and breeding. Xinong 511 (XN511) is a high-quality wheat variety widely cultivated in the Yellow and Huai Rivers Valley of China with stable FHB-resistance. Through analysis of pedigree materials of the wheat cultivar XN511, we found that the genetic material and FHB resistance from Th. ponticum were transmitted to the introgression line, indicating that the FHB resistance in XN511 likely originates from Th. ponticum. To further explore the genetic basis of FHB resistance in XN511, QTL mapping was conducted using the RILs population of XN511 and the susceptible line Aikang 58 (AK58). Survey with makers closely-linked to Fhb1, Fhb2, Fhb4, Fhb5, and Fhb7, indicated that both XN511 and the susceptible lines do not contain these QTL. Using bulked segregant analysis RNA-seq (BSR-Seq) and newly developed allele-specific PCR (AS-PCR) markers, QTLs in XN511 were successfully located on wheat chromosomes 5B and 7A. These findings are significant for further understanding and utilizing FHB resistance genes in wheat improvement.

A Glutathione S-Transferase from Thinopyrum ponticum Confers Fhb7 Resistance to Fusarium Head Blight in Wheat.

Fusarium head blight (FHB), mainly incited by Fusarium graminearum, has caused great losses in grain yield and quality of wheat globally. Fhb7, a major gene from 7E chromosome of Thinopyrum ponticum, confers broad resistance to multiple Fusarium species in wheat and has recently been cloned and identified as encoding a glutathione S-transferase (GST). However, some recent reports raised doubt about whether GST is the causal gene of Fhb7. To resolve the discrepancy and validate the gene function of GST in wheat, we phenotyped Fhb7 near-isogenic lines (Jimai22-Fhb7 versus Jimai22) and GST overexpressed lines for FHB resistance. Jimai22-Fhb7 showed significantly higher FHB resistance with a lower percentage of symptomatic spikelets, Fusarium-damaged kernels, and deoxynivalenol content than susceptible Jimai22 in three experiments. All the positive GST transgenic lines driven by either the maize ubiquitin promoter or its native promoter with high gene expression in the wheat cultivar 'Fielder' showed high FHB resistance. Only one maize ubiquitin promoter-driven transgenic line showed low GST expression and similar susceptibility to Fielder, suggesting that high GST expression confers Fhb7 resistance to FHB. Knockout of GST in the Jimai22-Fhb7 line using CRISPR-Cas9-based gene editing showed significantly higher FHB susceptibility compared with the nonedited control plants. Therefore, we confirmed GST as the causal gene of Fhb7 for FHB resistance. Considering its major effect on FHB resistance, pyramiding Fhb7 with other quantitative trait loci has a great potential to create highly FHB-resistant wheat cultivars.

Investigating the mechanisms of isochorismate synthase: An approach to improve salicylic acid synthesis and increase resistance to Fusarium head blight in wheat

Salicylic acid (SA), a vital endogenous hormone, plays a crucial role in plant growth and the response to abiotic and biotic stress. Isochorismate synthase (ICS) and phenylalanine ammonia lyase (PAL) are critical rate-limiting enzymes for SA synthesis. Fusarium head blight (FHB) seriously threatens the safety of wheat production, but increasing the content of SA can enhance FHB resistance. However, the pathway of SA synthesis and regulation in wheat remains unknown. In this study, three wheat ICS (TaICSA, TaICSB, and TaICSD) were identified, and their functions were validated in vitro for isomerizing chorismate to isochorismate. The mutation of one or two homoeoalleles of TaICSA, TaICSB, and TaICSD in the wheat variety ‘Cadenza’ reduced SA levels under ultraviolet treatment and Fusarium graminearum infection, further enhancing sensitivity to FHB. Overexpression of TaICSA can significantly enhance SA levels and resistance to FHB. To further study SA synthesis pathways in wheat and avoid interference with pathogenicity related genes, the leaves of wild-type Cadenza and different TaICS mutant lines were subjected to ultraviolet treatment for transcriptomic analysis. The results showed that 37 PALs might be involved in endogenous SA synthesis, and 82 WRKY and MYB family transcription factors may regulate the expression of ICS and PAL. These results were further confirmed by RT-PCR. In conclusion, this study expands our knowledge of SA biosynthesis and identifies TaICSA, as well as several additional candidate genes that encode transcription factors for regulating endogenous SA levels, as part of an efficient strategy for enhancing FHB resistance in wheat.

Mapping of main and hidden epistatic QTL effects in spring wheat population using medium parental FHB resistance

Fusarium head blight (FHB) is a devastating disease lowering the yield and quality of wheat. Intensive use of limited allelic pools critically affects wheat resistance, while advancing pathogenic alleles. This study presents new alleles raised from moderate rather than elite crosses. ‘Parshall’ has indigenous moderate resistance that was crossed with the moderate susceptible ‘Reeder’ and developed the 110 RIL population (noted as PR) that was tested across three states and years in the USA, under open-field and greenhouse conditions. Heading- and FHB-related traits of incidence, severity, and index were assessed. A genetic map (1417 cM) of SNP/DArT markers was generated. Composite interval mapping produced 45 QTL. Permutated LOD assessment identified two consistent QTL (4AL and 4BL) of type I and II resistance. Significant markers at the 4A QTL showed correlation with previous FHB resistance, while at the 4B QTL with pathogen responsive regions. The 1- and 2-D genome scans identified 16 QTL and six pairs of interacting markers for resistance, with additive effects between 0.17% and 2.19%; respectively. Additionally, additive × environment interaction was between 0.04% and 3.18% confirming the high environmental effect. Three pairs of QTL with additive × additive effects between 0.15% and 0.30% were revealed by FHB epistasis. However, the additive × additive environmental interaction at these three loci varied between 0.03% and 1%, confirming the G × E effect on FHB resistance. Hidden heritable epistasis was discovered in PR-population for FHB resistance. PR-alleles will help breeders develop lines mitigating epidemic environments and changeable climates, to boost yield facing hanger, food scarce, and secure worldwide penurious economies.

Integrating genomics, phenomics, and deep learning improves the predictive ability for Fusarium head blight-related traits in winter wheat.

Fusarium head blight (FHB) remains one of the most destructive diseases of wheat (Triticum aestivum L.), causing considerable losses in yield and end-usequality. Phenotyping of FHB resistance traits, Fusarium-damaged kernels (FDK), and deoxynivalenol (DON), is either prone to human biases or resource expensive, hindering the progress in breeding for FHB-resistant cultivars. Though genomic selection (GS) can be an effective way to select these traits, inaccurate phenotyping remains a hurdle in exploiting this approach. Here, we used an artificial intelligence (AI)-based precise FDK estimation that exhibits high heritability and correlation with DON. Further, GS using AI-based FDK (FDK_QVIS/FDK_QNIR) showed a two-fold increase in predictive ability (PA) compared to GS for traditionally estimated FDK (FDK_V). Next, the AI-based FDK was evaluated along with other traits in multi-trait (MT) GS models to predictDON. The inclusion of FDK_QNIR and FDK_QVIS with days to heading as covariates improved the PA for DON by 58% over the baseline single-trait GS model. We next used hyperspectral imaging of FHB-infected wheat kernels as a novel avenue to improve the MT GS for DON. The PA for DON using selected wavebands derived from hyperspectral imaging in MT GS models surpassed the single-trait GS model by around 40%. Finally, we evaluated phenomic prediction for DON by integrating hyperspectral imaging with deep learning to directly predict DON in FHB-infected wheat kernels and observed an accuracy (R2=0.45) comparable to best-performing MT GS models. This study demonstrates the potential application of AI and vision-based platforms to improve PA for FHB-related traits using genomic and phenomic selection.

Comprehensive genome-wide analysis of wheat xylanase inhibitor protein (XIP) genes: unveiling their role in Fusarium head blight resistance and plant immune mechanisms.

In this comprehensive genome-wide study, we identified and classified 83 Xylanase Inhibitor Protein (XIP) genes in wheat, grouped into five distinct categories, to enhance understanding of wheat's resistance to Fusarium head blight (FHB), a significant fungal threat to global wheat production. Our analysis reveals the unique distribution of XIP genes across wheat chromosomes, particularly at terminal regions, suggesting their role in the evolutionary expansion of the gene family. Several XIP genes lack signal peptides, indicating potential alternative secretion pathways that could be pivotal in plant defense against FHB. The study also uncovers the sequence homology between XIPs and chitinases, hinting at a functional diversification within the XIP gene family. Additionally, the research explores the association of XIP genes with plant immune mechanisms, particularly their linkage with plant hormone signaling pathways like abscisic acid and jasmonic acid. XIP-7A3, in particular, demonstrates a significant increase in expression upon FHB infection, highlighting its potential as a key candidate gene for enhancing wheat's resistance to this disease. This research not only enriches our understanding of the XIP gene family in wheat but also provides a foundation for future investigations into their role in developing FHB-resistant wheat cultivars. The findings offer significant implications for wheat genomics and breeding, contributing to the development of more resilient crops against fungal diseases.

The effects of Lr34 and Lr67 on Fusarium head blight resistance and deoxynivalenol accumulation in wheat

AbstractThe resistance gene Lr34 conditions durable disease resistance to many biotrophic wheat pathogens and has been incorporated into many wheat cultivars throughout the world. Lr67 is a similar adult plant resistance gene that also conditions resistance to multiple wheat diseases. Both genes significantly reduce disease severity and work in an additive manner with other rust resistance genes. To determine the effect of Lr34 and Lr67 on Fusarium head blight (FHB), two doubled haploid populations, segregating for each of these genes, were developed in the Thatcher wheat background by crossing near‐isogenic lines. Progeny from these populations were tested in five Fusarium graminearum‐inoculated disease nurseries and assessed for FHB symptoms, using a visual rating index (VRI), and deoxynivalenol (DON) accumulation. Both Lr34 and Lr67 significantly reduced visual symptoms of FHB and DON overall, though those effects were not significant in all environments. The overall reduction in the group of progeny with the resistant allele compared to the group with the susceptible allele for VRI was 9.4% for Lr34 and 6.8% for Lr67, while for DON it was 16.4% for Lr34 and 14.9% for Lr67. These genes represent important tools for improving resistance to FHB and many other diseases in wheat.