Abstract Fusarium head blight (FHB) is a devastating disease that severely impacts global wheat (Triticum aestivum L.) production. Sumai 3, a wheat cultivar widely used in breeding programs for its strong FHB resistance, has not been fully resolved at the chromosome level. Here, we present a high‐quality chromosome‐scale assembly of Sumai 3 using PacBio HiFi reads and chromosome conformation capture sequencing. The 14.6 Gb assembly consists of 832 contigs, with the longest contig being 245.2 Mb and a contig N50 of 41.90 Mb, which were scaffolded into 21 pseudomolecules. De novo annotation identified 104,620 high‐confidence protein‐coding genes and found 92.67% of the genome to consist of repetitive sequences. Synteny analysis showed strong collinearity between Sumai 3 and the wheat reference sequence Chinese Spring IWGSC RefSeq v2.1 (CS). Structural variant analysis identified chromosome 2A with the highest number of deletions (2773) and insertions (2645), while chromosome 3B had the most inversions (359). Duplications were most frequent on 2A (337), and contractions on 5B (122). The gene content of the major resistance quantitative trait loci on 3B, Fhb1, largely validates previous annotations for CS, although we discovered two new genes at approximately 12.4 Mb, including an additional copy of a terpene synthase, further suggesting homology with CS 3D over 3B. Differential expression analysis highlighted up‐regulation of three genes coding pore‐forming toxin‐like protein, sina superfamily protein, and plastid‐lipid‐associated proteins potentially involved in FHB resistance. This assembly provides critical insights into FHB resistance and offers a valuable genomic resource for wheat breeding programs.
Rubylyn D. Mijan, Bikash Poudel, Sittal Thapa et al.· The Plant Genome· 0 citations
Integrating high-throughput phenotyping with multiple complementary GWAS models reduces method-dependent bias and enables reliable identification of novel loci and elite germplasm for durable yellow and leaf rust resistance in wheat. The causal agents of yellow and leaf rust in wheat, Puccinia striiformis f. sp. tritici and Puccinia triticina, pose a serious threat to grain yield and quality worldwide. Growing durable resistant wheat cultivars is an effective protection measure contributing to sustainable agriculture. Many of the known resistance genes, however, have been overcome due to the high genetic diversity and adaptability of pathogen populations. Therefore, the present study aimed to identify novel loci associated with yellow rust and leaf rust in a genome-wide association study using 1984 spring wheat accessions from the German Federal ex situ Genebank. Phenotypic data obtained from a detached-leaf assay were combined with 90,283 genotyping-by-sequencing genome-wide markers. Six significant peak marker-trait associations were identified for yellow rust and leaf rust, respectively. These are located on chromosomes 1D, 2B, 3B, 4A, 4B, 4D, 5A, 6B, and 7D. Six candidate genes were identified close to the identified loci. These findings may be valuable for identifying and deploying genetic resources to broaden the genetic basis of resistance and safeguard durability of resistance against yellow and leaf rust.
Behnaz Soleimani, Anne-Kathrin Pfrieme, Ulrike Beukert et al.· Theoretical and Applied Gene...· 0 citations
Structural variants (SVs) are abundant in plant genomes and influence agronomic traits, yet their regulatory interpretation remains challenging. Here, we combine pangenome-wide profiling of DNA methylation and chromatin accessibility across 20 barley genotypes, complemented by histone modification and chromatin interaction data in a subset of 10 genotypes. Comparative analysis of genotype-specific epigenomes reveals a globally conserved DNA methylation landscape across the barley pangenome alongside extensive regulatory variability at orthologous genes. We show that SVs do not broadly remodel global chromatin landscapes but instead act through context-dependent rewiring of local regulatory interactions. Despite this epigenomic stability, SVs may contribute to gene expression changes via chromatin contacts. Tissue-specific chromatin accessibility demonstrates that SV effects depend on developmental context. Integrating chromatin state variation with SVs at key vernalization genes explains epigenetic contributions to growth habit diversity. Together, these results provide a framework for interpreting the regulatory consequences of structural variation in crop genomes.
Zihao Zhu, Erwang Chen, Pavla Navrátilová et al.· bioRxiv· 0 citations
An improved rye genome assembly is presented and unique retrotransposon organizations within its centromeres are uncovered, revealing RLG_Abia and RLG_Abigail as abundant, recently active elements, unlike in wheat.
Erwang Chen, Carlotta Marie Wehrkamp, Srijan Jhingan et al.· Nature Communications· 0 citations
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