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Uauy, C.

Publications and source records attributed to Uauy, C..

At least 19 recordsLinked to original sources

EISCA and EISTA: Full-Spectrum Pipelines for Single-Cell and Spatial Transcriptomics Analysis

Single-cell and spatial transcriptomics are transforming our understanding of cellular heterogeneity and tissue organization, yet their analytical complexity remains a major bottleneck. Here, we present EISCA and EISTA, two standardized, end-to-end pipelines for single-cell RNA-seq and imaging-based spatial transcriptomics analysis. Built on the Nextflow nf-core framework, both pipelines implement modular, scalable, and reproducible workflows spanning primary, secondary, and tertiary analyses, from raw data processing to advanced downstream analyses. EISCA supports droplet- and plate-based scRNA-seq technologies, while EISTA is tailored for high-resolution spatial platforms including Vizgen MERFISH and 10x Xenium. Together, they integrate state-of-the-art methods for quality control, normalization, clustering, integration, cell-type annotation, differential expression, and cell-cell communication, with EISTA further enabling spatial statistical analyses. A central design principle is to balance standardization with flexibility: workflows can be executed end-to-end or modularly, enabling iterative, exploratory analyses with minimal overhead. Both pipelines deliver rapid preliminary results alongside an out-of-the-box report, facilitating immediate data assessment and accelerating downstream discovery. Case studies in plant immunity and human sepsis demonstrate that EISTA and EISCA reproducibly can be used to recover biologically meaningful insights. Collectively, these pipelines provide efficient, flexible, and scalable solutions for comprehensive single-cell and spatial transcriptomics analyses.

bioinformatics↗

Natural and breeding selection converge on overlapping haplotypes with divergent directions and outcomes in wheat

Understanding how natural and breeding selection interact to shape crop genomes is essential for improving resilience under climate change. Here, we applied a k-mer-based, alignment-free haplotype assignment approach to whole-genome resequencing data from 827 wheat landraces representing seven geographic groups and 208 modern cultivars. We identified haplotypes associated with local adaptation that were enriched in specific agroecological regions, many of which were derived from wild-relative introgressions. Comparative analyses revealed that natural and breeding selection largely targeted overlapping haplotype sets, but often drove them in opposite directions. Notably, haplotypes conferring adaptive advantages were frequently associated with negative regulation of agronomic traits, explaining their reduced prevalence among breeding-selected haplotypes. These results reveal the genomic basis of trade-offs between environmental adaptation and productivity and offer a framework for exploiting adaptive diversity in wheat improvement.

plant biology↗

Multi-Level Characterization Reveals Divergent Heat Response Strategies Across Wheat Genotypes of Different Ploidy

Understanding heat stress (HS) responses in wheat is important for breeding varieties adapted to increasing temperature. HS during grain filling reduces wheat yield, but transcriptional and alternative-splicing responses among wheat genotypes of different ploidy remain poorly characterized. We conducted two field experiments with diploid Triticum monococcum, tetraploid T. turgidum subsp. durum, and hexaploid T. aestivum. In Exp. 2, one genotype per species was exposed to severe HS for four consecutive days beginning 10 days after anthesis, and grains were sampled for RNA sequencing 3 h after treatment onset. Mean grain yield declined by 59.4%, 19.0%, and 37.9% in the diploid, tetraploid, and hexaploid genotypes, respectively, accompanied by reductions in thousand-grain weight. After homoeolog grouping, the tetraploid genotype had the smallest fraction of heat-responsive groups and the hexaploid the largest. HS also altered alternative splicing, with broader functional enrichment in the hexaploid genotype. In this genotype, all three homoeologs of an NF-YB gene showed heat-induced skipping of exon E6, and the splice products of the D-genome locus were confirmed by RT-PCR and Sanger sequencing. These results show that the three examined genotypes differed in phenotypic, transcriptional, and splicing responses to HS and identify NF-YB splicing as a candidate component of the hexaploid grain response. Main conclusionEarly grain-filling heating reduced yield and altered transcription and splicing in the three examined wheat genotypes, including increased NF-YB exon E6 skipping in the hexaploid wheat genotype.

plant biology↗

Design and deployment of a regulation-compliant infrared heating system for UK field trials.

Free-air warming systems are essential for simulating climate change in field conditions, yet most are not designed to meet UK or EU health and safety standards. We present the design and field deployment of a hexagonal Temperature-Free Air Controlled Enhancement (T-FACE) system that fully complies with these regulations. The system uses real-time, temperature-responsive control with multiple sensors to maintain a consistent temperature differential between heated and ambient temperature experimental plots. We describe its engineering design, performance, costs, and key operational challenges, particularly related to heater reliability under continuous use. We tested the T-FACE system during the winter months of a field sown wheat crop. Phenotypic evaluation showed effects of heating on heading date, plant height, spike length, and spikelet number, suggesting the system potential. This proof-of-concept provides a scalable, regulation-compliant approach for studying crop responses to climate warming under realistic field conditions.

plant biology↗

Increased grain weight conferred by GW2 mutations in wheat does not translate into yield gains in multi-year field trials of near-isogenic lines

Multiple studies have identified genes affecting grain morphology, yet their capacity to deliver yield gains under field conditions remains unclear. We performed a multiyear, multilocation factorial evaluation of GRAIN WIDTH2 (TaGW2) mutants in hexaploid wheat using BC4 near-isogenic lines, sowing-density treatments and semi-dwarfing RHT1 backgrounds. Loss-of-function mutations in TaGW2 increased grain size and thousand grain weight (TGW) additively; with the aaBBDD single mutant showing the most stable singlelocus effect, while the aabbdd triple mutant achieved ~20% higher TGW across twelve field trials. However, overall grain yield remained unchanged or slightly reduced, reflecting a compensatory trade-off with grain number. Spike phenotyping of both main and secondary tillers showed comparable increases in TGW and spike yield despite fewer grains per spike, indicating that limited yield gain primarily reflects reduced spike number per unit area rather than decreased spike-level productivity. Effects were stable across sowing densities, whereas interactions with semi-dwarfing alleles were allele-specific: RHT-B1b partially suppressed TGW gains and accentuated yield penalties, whereas RHT-D1b maintained the large-grain phenotype and productivity. Across experiments, the TaGW2-A1D1 double mutant increased TGW (~14%) while maintaining yield stability, identifying it as a promising genotype for breeding. We conclude that TaGW2 is a reliable modifier of grain size but not yield in isolation.

plant biology↗

KCFtools: Rapid alignment-free method for introgression screening and GWAS using k-mer profiles

MotivationIn the era of multiple genome references, researchers often align sequencing reads against distinct assemblies or even multiple references simultaneously. This enables applications such as the detection of introgressed segments or highly variable genomic regions, which are especially prevalent in large-genome crop species such as lettuce or wheat. However, these applications come at the cost of increased computational burden, inconsistencies in mapping methods, and reduced reproducibility across studies. To address these limitations, we developed KCFtools, a Java-based toolkit that identifies the presence and absence of k-mers in non-overlapping genomic or transcriptomic windows by comparing query and reference genomes. This alignment-free approach enables the efficient computation of an identity score for each window, thereby facilitating robust detection of introgressed or variable regions across genomes. ResultsWe systematically evaluated the performance and accuracy of the k-mer-based method implemented in KCFtools, benchmarking it against conventional SNP-based introgression detection pipelines. Our results demonstrate that KCFtools effectively captures introgressed segments and structurally diverse regions, even in species with fragmented or highly divergent reference genomes. In addition, we extended KCFtools to generate genotype matrices from k-mer variation tables. These matrices are compatible with Genome-Wide Association Studies (GWAS) software and allow the identification of loci associated with phenotypic traits. We showcase the utility of this approach by detecting known and novel associations for downy mildew resistance in lettuce, underscoring the pipelines potential for high-resolution, reference-agnostic population genetic analysis. Availabilityhttps://github.com/sivasubramanics/kcftools Contactc.s.sivasubramani@gmail.com

bioinformatics↗

Controlling GRF4-GIF1 Expression for Efficient, Genotype-Independent Transformation Across Wheat Cultivars

Bread wheat (Triticum aestivum L.) plays a vital role in global food security, and its continuous genetic improvement is essential to meet the demands of a rapidly growing world population. Advances in genome sequencing and assembly have positioned wheat as a model crop for functional genomics and have increased the demand for highly efficient, genotype-independent transformation systems. A fusion technology involving a GROWTH-REGULATING FACTOR (GRF) and a GRF-INTERACTING FACTOR (GIF) has emerged as a powerful tool to enhance regeneration efficiency and expand the range of transformable genotypes. In this study, we present an optimized and robust Agrobacterium-mediated wheat transformation protocol incorporating GRF4-GIF1, tested across multiple wheat varieties. Across all tested wheat cultivars, GRF4-GIF1 containing constructs consistently enabled successful transformation, with varied efficiencies depending on the genotype and promotors used to drive the gene fusion. Our method significantly improves transformation efficiency while minimizing GRF4-GIF1 pleiotropic effects, providing a versatile platform for gene function analysis and gene editing. This work represents a critical step toward efficient, genotype-independent transformation in wheat, supporting both research and breeding applications aimed at improving crop resilience, nutritional value, and productivity.

plant biology↗

The cellular architecture of wheat leaves supports a conservation of spatial patterning of the mesophyll in grasses

Classical botany identifies a clear adaxial/abaxial (palisade/spongy) patterning of the mesophyll in leaves of eudicots but suggest that there is no comparable overt pattern within the mesophyll of most grasses. In this paper, we report on an analysis of leaves from across ploidy levels of Triticum species which reveals a patterning of mesophyll cellular architecture that has been maintained during the evolution/selection of wheat. Taking a quantitative approach to the analysis of 2D and 3D images, we show that upper and lower mesophyll cells are larger than the middle mesophyll cells, which are themselves more lobed than the mesophyll cells adjoining the upper and lower epidermis. This mesophyll patterning is superimposed on a gradual increase of cell size with ploidy, suggesting that it is evolutionarily ancient. Taken in the context of data revealing patterning of the rice mesophyll, our data support the hypothesis that grass leaves do display distinct cellular patterning across the adaxial/abaxial axis, the functional significance of which awaits full elucidation.

plant biology↗

TaWUS2D regulates the number of grains per spikelet by enhancing the number of fertile ovaries in Multi-Ovary Wheat

Innovative genetic improvements in the staple crop Triticum aestivum (bread wheat) are urgently needed to address the growing global food security crisis. Here, we report the map-based cloning of TaWUS2D, the gene responsible for the dominant multi-ovary phenotype in wheat. Multi-ovary lines are characterized by the development of three fertile ovaries per floret that results in three grains, as opposed to wildtype single ovary wheat. We used HiFi long-reads to assemble a 14.48 Gbp genome scaffold assembly in the background of mutli-ovary wheat line MOV. Using high-resolution genetic mapping, combined with additional genomic resources, we defined the Mov-1 locus to a 135 Kbp region containing two genes. Using five independent deletion mutants and eight TILLING mutants, we demonstrate that a functional WUSCHEL-like protein, TaWUS2D, is required for the multi-ovary phenotype. TaWUS2D is upregulated in the MOV genetic background. This research lays the groundwork for developing new approaches to improve wheat production potential and sustainability in the face of current and future global food challenges.

plant biology↗

Decoding cellular transcriptional regulatory networks governing wheat inflorescence development

Wheat inflorescence architecture, particularly spikelet and floret development, is critical for grain yield. To decode the cellular transcriptional regulatory network (cTRN) underlying wheat inflorescence development, we integrated multiple single-cell omics technologies to construct a spatiotemporal atlas of transcriptional and chromatin accessibility dynamics. This comprehensive analysis identified 20 cell types, 7,211 cell type-specific genes and 152,333 cell type-specific accessible chromatin regions (csACRs) in the wheat inflorescence. Trajectory analysis identified two sub-clusters of proliferating cells as the origins of spikelet and floret formation, deviating from the traditional developmental model. Key transcription factors and hormone-related genes in the cTRN, along with the csACRs, providing new targets for modulating wheat inflorescence architecture. Our findings provide a high-resolution resource for crop inflorescence research and establish a paradigm for applying spatiotemporal single-cell omics analysis to plant biology.

plant biology↗

Spatial Transcriptomics Reveals Expression Gradients in Developing Wheat Inflorescences at Cellular Resolution

The diversity of plant inflorescence architectures is specified by gene expression patterns. In wheat (Triticum aestivum), the lanceolate-shaped inflorescence (spike) is defined by rudimentary spikelets at the base which initiate first but subsequently lag in development compared with central spikelets. While previous studies identified gene expression differences between central and basal inflorescence sections, the spatio-temporal dynamics and gradients along the apical-basal axis remain poorly resolved due to bulk tissue-level techniques. Here, using spatial transcriptomics, we profiled 200 genes across four stages of wheat inflorescence development to cellular resolution. Cell segmentation and unsupervised clustering identified 18 expression domains and their enriched genes, revealing dynamic spatio-temporal organisation along the apical-basal axis of the inflorescence. Along this axis, we uncovered distinct and spatially coordinated gene expression gradients patterning meristems prior to the visible delay in basal spikelet development. This study demonstrates the potential for spatial transcriptomics time-series to advance plant developmental biology.

plant biology↗

Natural variations of TaMYB7-A1 regulate PHS resistance and specify wheat geographic adaptation

Crop domestication tended to select against seed dormancy for uniform germination--raising risks of undesirable pre-harvest sprouting (PHS) -- but regulation of seed dormancy and PHS in wheat are grossly under-characterized. Here, we identified wheat PHS resistance loci by GWAS. TaMYB7-A1 confers PHS resistance by elevating ABA signaling and seed dormancy in grains. Three TaMYB7-A1 haplotypes (Hap-1/2/3) contrast in PHS resistance, with Gly23 and Gly92 crucial for binding to and activating TaABI5 in Hap-1/3. A MITE transposon in the TaMYB7-A1Hap-1 promoter likely recruited the TaAZF1-TaABI4 module to boost expression, resulting in strong PHS resistance. TaMYB7-A1Hap-1 originated from wild einkorn and was integrated into hexaploid wheat through introgression into wild emmer. Different haplotypes of TaMYB7-A1, in conjunction with alleles of other major PHS resistance genes, is pivotal in shaping wheats adaptability to rainfall conditions in China, US and Europe during the harvest season. Introduction of TaMYB7-A1Hap-1 into elite cultivars confers PHS resistance without yield defects. Thus, artificial and natural selection across diverse climates regions have collectively shaped wheat adaptation and enabled rational delivery of improved lines tailored to local cropping needs.

plant biology↗

TILLCANN: A TILLING platform in Cannabis sativa for mutation discovery and crop improvement

Cultivation of Cannabis sativa is increasing because of its therapeutic value and recognition as a multi-purpose and sustainable crop. Targeting Induced Local Lesions in Genomes (TILLING) is a versatile reverse genetics approach that unlocks induced variation through mutagenesis to accelerate the development of new cultivars and contribute to the functional validation of genes. Increasingly efficient next-generation sequencing technologies and genomic resources have combined to make TILLING by sequencing (TbyS) an attractive technique that can be applied in cannabis. Here we describe the development of a mutagenesis protocol for C. sativa and the development of the TILLCANN platform composed of 1,633 M2 families. As a demonstration of the functionality of the platform, we used TbyS to perform a high throughput screening of novel mutations in amplicons for genes associated with important agronomic and biochemical traits in a set of 512 M2 families. We confirmed 14 of the identified mutations and calculated an average mutation frequency range of 1/263 to 1/320 kb. We found that heterozygous mutants in the cannabis homologue of Class II TEOSINTE BRANCHED 1/CYCLOIDEA/PCF (TCP4) are linked to alterations in leaf number and morphology. We expect that the novel genetic variability unlocked in the TILLCANN platform for performing forward or reverse genetic screens can significantly boost breeding programs geared toward both medicinal cannabis and industrial hemp. Gene & accession numbersRaw sequencing data generated in this study was deposited at the European Nucleotide Archive with accession numbers xxx and xxx. Genes and accession numbers discussed within this manuscript correspond to the Cannabis sativa cs10 genome assembly deposited in National Center for Biotechnology Information with accession number GCA_900626175.2.

plant biology↗

A curve fitting method for analysing starch granule size distributions in cereals

Background and ObjectivesThe size distribution of starch granules is an important factor determining functional and nutritional properties of starch. However, a simple, standardised method for their analysis is lacking. Here, we developed an approach for estimating granule size parameters using a Python script that fits curves to volumetric granule size distributions generated using a Coulter counter. FindingsThe bimodal size distribution of starch from most wheat and barley cultivars could be best described with a mixed distribution curve. A log-normal distribution was fitted to the small B-type granules, and a normal distribution was fitted to the large A-type granules, allowing estimation of their relative abundance and size parameters, despite their overlapping size distributions. However, the optimal fitting is altered in wheat mutants with large perturbations in B-type granule content. In maize and rice, which have unimodal granule size distributions, size parameters were calculated by fitting a single normal distribution. ConclusionsCurve fitting is an effective approach for estimating starch granule size parameters in diverse cereals, particularly the Triticeae with A- and B-type granules. Significance and noveltyWe provide new tools and guidelines for the quantitative analysis of granule size in cereals.

plant biology↗

Population genomics uncover loci for trait improvement in the indigenous African cereal tef (Eragrostis tef)

Tef (Eragrostis tef) is an indigenous African cereal that is gaining global attention as a gluten-free "superfood" with high protein, mineral, and fibre contents. However, tef yields are limited by lodging and by losses during harvest owing its small grain size (150x lighter than wheat). Breeders must also consider a strong cultural preference for white-grained over brown-grained varieties. Tef is relatively understudied with limited "omics" resources. Here, we resequenced 220 tef accessions from an Ethiopian diversity collection and also conducted multi-locational phenotyping for 25 agronomic and grain traits. Grain metabolome profiling revealed differential accumulation of fatty acids and flavonoids between white and brown grains. We conducted k-mer and SNP-based genome wide association and uncovered novel marker-trait associations. A significant 70 kb peak for panicle morphology contained the tef orthologue of rice qSH1, a transcription factor regulating inflorescence morphology in cereals. We also observed a previously unknown relationship between grain size, colour, and fatty acids. These traits were highly associated with retrotransposon insertions in homoeologues of TRANSPARENT TESTA 2, a known regulator of grain colour. Our study provides valuable resources for tef research and breeding, facilitating the development of improved cultivars with desirable agronomic and nutritional properties.

genomics↗

Stigma longevity is not a major limiting factor in hybrid wheat seed production

Hybrids offer a promising approach to improve crop performance because the progeny are often superior to their parent lines and they outyield inbred varieties. A major challenge in producing hybrid progeny in wheat, however, lies in the low outcrossing rates of the maternal parent. This is often attributed to suboptimal synchronisation of male and female flowering as delayed pollination can result in reproductive failure due to female stigma deterioration. To test this accepted dogma, we examined the seed set capacity of six male sterile (MS) cultivars, each varying in the onset of stigma deterioration. To mimic a hybrid seed production scenario, MS cultivars were grown during two consecutive field seasons, and open pollination was allowed up to 15 days after flowering of the female parent using a blend of seven male fertile cultivars with varying flowering times. Detailed analysis of the temporal and spatial distribution of hybrid seed set along the spike across the six MS cultivars showed that grain production remained remarkably stable during the pollination window tested. These findings suggest sustained receptivity of stigma to pollen across all tested MS cultivars throughout the entire time course. We therefore conclude that stigma longevity does not represent a limiting factor in hybrid wheat seed production, and that breeding efforts should prioritise the study of other female traits, such as enhanced access to airborne pollen.

plant biology↗

Modern wheat breeding selection synergistically improves above- and below-ground traits

The root system, as a fundamental organ for uptaking water and nutrients and interacting with the local environmental conditions, has been postulated to be the foundation for a second Green Revolution. However, the status of the root system during modern wheat breeding remains to be elucidated. Here, by analyzing the phenotypes of 406 wheat accessions on a large scale, we found the root systems of modern cultivars were synchronisely changed along with the above-ground traits. Furthermore, the genomic blocks with phenotypic effects on both above- and below-ground traits were observed to be enriched in the selection sweeps, highlighting that modern wheat breeding contributed to the synchronised changes. More importantly, the haplotypes selected by breeders within the selection sweeps synergistically improved both the above- and below-ground traits, suggesting that modern wheat breeding has improved the root system indirectly, which may contribute to the higher grain yields of modern wheat cultivars. Our results demonstrated that modern wheat breeding synergistically improved the above- and below-ground traits.

genetics↗

Chromosome-scale assembly of the African yam bean genome

Genomics-informed breeding of locally adapted, nutritious, albeit underutilised African crops can help mitigate food and nutrition insecurity challenges in Africa, particularly against the backdrop of climate change. However, utilisation of modern crop improvement tools including genomic selection and genome editing for many African indigenous crops is hampered by the scarcity of genetic and genomic resources. Here we report on the assembly of the genome of African yam bean (Sphenostylis stenocarpa), a tuberous legume crop that is indigenous to Africa. By combining long and short read sequencing with Hi-C scaffolding, we produced a chromosome-scale assembly with an N50 of 69.5 Mbp and totalling 649 Mbp in length (77 - 81% of the estimated genome size based on flow cytometry). Using transcriptome evidence from Nanopore RNA-Seq and homology evidence from related crops, we annotated 31,614 putative protein coding genes. We further show how this resource improves anchoring of markers, genome-wide association analysis and candidate gene analyses in Africa yam bean. This genome assembly provides a valuable resource for genetic research in Africa yam bean.

genomics↗