Publications by authors named "Brian J Steffenson"

Article Synopsis
  • The population structure and evolution of basidiomycetes, such as rust fungi, are shaped by complex reproductive strategies that include both asexual and sexual reproduction, which enhance their adaptability.
  • Puccinia coronata f. sp. avenae (Pca), a significant oat pathogen, exhibits varied contributions from sexual reproduction, clonality, and genetic exchange to its evolution, leading to challenges in managing host resistance.
  • Recent genome sequencing of Pca isolates from the USA, Australia, Taiwan, and South Africa revealed genetic recombination and somatic hybridization, indicating increased genetic diversity and potential intercontinental movement of strains, highlighting the need for global pathogen monitoring.
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Nucleotide-binding leucine-rich repeat (NLR) disease resistance genes typically confer resistance against races of a single pathogen. Here, we report that Yr87/Lr85, an NLR gene from Aegilops sharonensis and Aegilops longissima, confers resistance against both P. striiformis tritici (Pst) and Puccinia triticina (Pt) that cause stripe and leaf rust, respectively.

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Pangenomes are collections of annotated genome sequences of multiple individuals of a species. The structural variants uncovered by these datasets are a major asset to genetic analysis in crop plants. Here we report a pangenome of barley comprising long-read sequence assemblies of 76 wild and domesticated genomes and short-read sequence data of 1,315 genotypes.

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Bread wheat (Triticum aestivum) is a globally dominant crop and major source of calories and proteins for the human diet. Compared with its wild ancestors, modern bread wheat shows lower genetic diversity, caused by polyploidisation, domestication and breeding bottlenecks. Wild wheat relatives represent genetic reservoirs, and harbour diversity and beneficial alleles that have not been incorporated into bread wheat.

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Rusts of the genus are wheat pathogens. Stem (black; Sr), leaf (brown; Lr), and stripe (yellow; Yr) rust, caused by f. sp.

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Control of stem rust, caused by Puccinia graminis f.sp. tritici, a highly destructive fungal disease of wheat, faces continuous challenges from emergence of new virulent races across wheat-growing continents.

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Introduction: Members of the family Geminiviridae have been reported to infect either a monocot plant or a dicot plant, but not both. This study reports a geminivirus, Wheat Dwarf India Virus (WDIV), first identified in wheat, that is capable of infecting both monocot and dicot plants and acting as a viral vector.

Objectives: This study was aimed at developing a broad host range viral vector system for reverse genetics and genome editing.

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The rust diseases, including leaf rust caused by (), stem rust caused by f. sp. (), and stripe rust caused by f.

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Barley leaf rust, caused by , is an important disease of barley worldwide. The pathogen can develop new races that overcome resistance genes, emphasizing the need for monitoring its virulence. This study characterized 519 isolates collected in the United States from the 1989 to 2000 and 2010 to 2020 survey periods on 15 (Reaction to ) genes.

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To safeguard bread wheat against pests and diseases, breeders have introduced over 200 resistance genes into its genome, thus nearly doubling the number of designated resistance genes in the wheat gene pool. Isolating these genes facilitates their fast-tracking in breeding programs and incorporation into polygene stacks for more durable resistance. We cloned the stem rust resistance gene Sr43, which was crossed into bread wheat from the wild grass Thinopyrum elongatum.

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Bacterial leaf streak (BLS), caused chiefly by the pathogen pv. , is becoming an increasingly important foliar disease of barley in the Upper Midwest. The deployment of resistant cultivars is the most economical and practical method of control.

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is a necrotrophic fungal pathogen that causes foliar and root diseases on wheat and barley. These diseases are common in all wheat- and barley-growing regions, with more severe outbreaks occurring under warm and humid conditions. can also infect a wide range of grass species in the family Poaceae and secrete , an important necrotrophic effector also identified other wheat leaf spotting pathogens.

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Genetic manipulation of whole-plant transpiration rate (TR) response to increasing atmospheric vapor pressure deficit (VPD) is a promising approach for crop adaptation to various drought regimes under current and future climates. Genotypes with a non-linear TR response to VPD are expected to achieve yield gains under terminal drought, thanks to a water conservation strategy, while those with a linear response exhibit a consumptive strategy that is more adequate for well-watered or transient-drought environments. In wheat, previous efforts indicated that TR has a genetic basis under naturally fluctuating conditions, but because TR is responsive to variation in temperature, photosynthetically active radiation, and evaporative demand, the genetic basis of its response VPD per se has never been isolated.

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Bacterial leaf streak (BLS) is a sporadic yet damaging disease of cereals that is growing in importance across the Upper Midwest production region. In barley ( ssp. ), this disease is caused primarily by the bacterium pv.

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The distribution of recombination events along large cereal chromosomes is uneven and is generally restricted to gene-rich telomeric ends. To understand how the lack of recombination affects diversity in the large pericentromeric regions, we analysed deep exome capture data from a final panel of 815 Hordeum vulgare (barley) cultivars, landraces and wild barleys, sampled from across their eco-geographical ranges. We defined and compared variant data across the pericentromeric and non-pericentromeric regions, observing a clear partitioning of diversity both within and between chromosomes and germplasm groups.

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Advances in sequencing technologies as well as development of algorithms and workflows have made it possible to generate fully phased genome references for organisms with nonhaploid genomes such as dikaryotic rust fungi. To enable discovery of pathogen effectors and further our understanding of virulence evolution, we generated a chromosome-scale assembly for each of the 2 nuclear genomes of the oat crown rust pathogen, Puccinia coronata f. sp.

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The wild relatives and progenitors of wheat have been widely used as sources of disease resistance (R) genes. Molecular identification and characterization of these R genes facilitates their manipulation and tracking in breeding programmes. Here, we develop a reference-quality genome assembly of the wild diploid wheat relative Aegilops sharonensis and use positional mapping, mutagenesis, RNA-Seq and transgenesis to identify the stem rust resistance gene Sr62, which has also been transferred to common wheat.

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Precise segmentation of wheat spikes from a complex background is necessary for obtaining image-based phenotypic information of wheat traits such as yield estimation and spike morphology. A new instance segmentation method based on a Hybrid Task Cascade model was proposed to solve the wheat spike detection problem with improved detection results. In this study, wheat images were collected from fields where the environment varied both spatially and temporally.

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Climate changes leading to higher summer temperatures can adversely affect cool season crops like spring barley. In the Upper Midwest region of the United States, one option for escaping this stress factor is to plant winter or facultative type cultivars in the autumn and then harvest in early summer before the onset of high-temperature stress. However, the major challenge in breeding such cultivars is incorporating sufficient winter hardiness to survive the extremely low temperatures that commonly occur in this production region.

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Crop losses caused by plant pathogens are a primary threat to stable food production. Stripe rust (Puccinia striiformis) is a fungal pathogen of cereal crops that causes significant, persistent yield loss. Stripe rust exhibits host species specificity, with lineages that have adapted to infect wheat and barley.

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Article Synopsis
  • Aegilops tauschii is a wild ancestor of bread wheat that contains valuable genetic diversity for enhancing wheat's performance and resilience.
  • Researchers sequenced 242 accessions of Ae. tauschii and discovered a unique lineage from Georgia that contributed to the development of modern bread wheat.
  • Using advanced mapping techniques, they identified key genomic regions linked to disease and pest resistance and successfully transferred these traits into wheat, facilitating faster trait discovery for breeding.
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Fine mapping of barley 6H pericentromeric region identified FHB QTL with opposite effects, and high grain protein content was associated with increased FHB severity. Resistance to Fusarium head blight (FHB), kernel discoloration (KD), deoxynivalenol (DON) accumulation and grain protein content (GPC) are important traits for breeding malting barley varieties. Previous work mapped a Chevron-derived FHB QTL to the pericentromeric region of 6H, coinciding with QTL for KD resistance and GPC.

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