Biology subjects

Grumet, R.

Publications and source records attributed to Grumet, R..

6 recordsLinked to original sources

bioRxiv2026

Graph-based pangenome provides insights into the adaptive evolution of Cucurbita pepo

Understanding how crops respond to environmental variation is crucial for biodiversity conservation and food security. Cucurbita pepo (pumpkin, squash, gourd) is one of the first domesticated crop species and exhibits remarkable phenotypic and ecological diversity, making it a powerful system for investigating the genomic basis of adaptation. Here, we constructed a graph-based C. pepo pangenome using nine chromosome-level assemblies and identified 229,431 high-confidence structural variants (SVs) that were genotyped across 206 wild and cultivated accessions. Our results demonstrate that C. pepo underwent parallel domestication, with two deeply diverged gene pools independently giving rise to the pepo and ovifera cultivated lineages, followed by expansion into diverse environments that produced strong signatures of differentiation largely mediated by young adaptive alleles. Single-nucleotide polymorphisms (SNPs) and SVs contribute complementary dimensions of environmental responsiveness. Biogeographical modeling predicts continued range contraction of wild relatives and elevated genetic offset in Eastern North American populations under projected future climates. Populations with higher genetic load harbor fewer adaptive variants and exhibit greater predicted maladaptation, indicating that deleterious mutations constrain adaptive potential. These findings highlight how genomic variants, adaptive diversity, and genetic load together shape environmental adaptation and inform conservation and crop improvement.

genomics↗

bioRxiv2025

Population-level super-pangenome reveals genome evolution and empowers precision breeding in watermelon

Pangenomes are increasingly critical for harnessing crop genetic diversity, yet their resolution and utility are often limited by insufficient sampling of high-quality genome assemblies. Here, we report a population-level watermelon super-pangenome constructed from 138 reference-grade assemblies, including 135 newly generated near-gapless genomes representing all seven watermelon species. The super-pangenome captures approximately one million structural variants (SVs), enabling accurate variant genotyping across ~900 watermelon accessions and substantially expanding variant discovery both across and within species. Broader sampling within the pangenome provides insights into genome evolution among watermelon species and sheds light on the origin of cultivated watermelon. SV-inclusive genome-wide association studies enhance trait mapping resolution and identify a copy number variation upstream of ClFCI1 that regulates flesh color intensity in a dosage-dependent manner. Leveraging this comprehensive variation map, we developed high-accuracy genomic prediction models for 18 agronomic traits. Together, our findings and genomic resources establish a foundational framework for dissecting complex traits and accelerating precision breeding in watermelon, while offering a valuable model for SV-resolved pangenomics in crop species.

plant biology↗

bioRxiv2025

Graph pangenome reveals structural variation dynamics during cucumber breeding

Structural variants (SVs) represent a significant yet underexplored component of plant genome diversity. Analyzing SV dynamics is important for understanding their contributions to phenotypic variation and their influence on genome evolution. Here, we present a graph-based pangenome for cucumber, constructed from 39 reference-level genome assemblies. The pangenome captures 171,892 high-confidence SVs and enables genotyping of these SVs across 443 cucumber accessions, representing diverse geographic origins and spanning wild progenitors, landraces, and modern cultivars. Our analyses reveal that during cucumber domestication, a substantial portion of mildly deleterious SNPs are retained, whereas SVs are consistently purged, highlighting their potentially highly deleterious nature. During the geographic expansion of cucumber, a reduction in SV burden and a younger age of SVs than SNPs were observed, suggesting stronger purifying selection acting on SVs. Additionally, notable gene flow from wild population to African and European populations was detected, resulting in an increased SV burden, potentially due to hitchhiking effects. Importantly, incorporating SV burden into genomic prediction models improved the prediction accuracy for several agronomically important traits. This study illuminates the dynamics of SVs during cucumber domestication and improvement, highlights the complex interplay between SVs and selection pressures, and underscores the extensive implications of SVs for future cucumber breeding.

plant biology↗

bioRxiv2023

Genetic factors acting prior to dormancy in sour cherry influence bloom time the following spring

Bloom time is central to tree fruit production, and for Prunus species floral development leading up to bloom spans four seasons. Understanding this entire process is crucial for developing strategies to manipulate bloom time to prevent crop loss due to climate change. Here, we present a detailed examination of flower development from initiation until bloom for early- and late-blooming sour cherries (Prunus cerasus) from a population segregating for a major bloom time QTL on chromosome 4. Using a new staging system, we identified floral buds from early-blooming trees were persistently more advanced than those from late-blooming siblings. A gDNA coverage analysis revealed the late-blooming haplotype of this QTL, k, is located on a subgenome originating from the late-blooming P. fruticosa progenitor. Transcriptome analyses identified a large number of genes within this QTL as differentially expressed between early- and late-blooming trees during the vegetative-to-floral transition. From these, we identified candidate genes for the late bloom phenotype, including multiple transcription factors homologous to REproductive Meristem (REM) B3 domain-containing proteins. Additionally, we determined the basis of k in sour cherry is likely separate from candidate genes found in sweet cherry - suggesting several major regulators of bloom time are located on Prunus chromosome 4. HIGHLIGHTDormancy is a main effector of bloom time in fruit trees. However, developmental, genetic, and transcriptomic analyses indicate differences in flower development before dormancy significantly influence flowering time in cherry.

plant biology↗

bioRxiv2020

Developmentally regulated activation of defense allows for rapid inhibition of infectionin age-related resistance to Phytophthora capsici in cucumber fruit

BackgroundAge-related resistance (ARR) is a developmentally regulated phenomenon conferring resistance to pathogens or pests. Although ARR has been observed in several host-pathogen systems, the underlying mechanisms are largely uncharacterized. In cucumber, rapidly growing fruit are highly susceptible to Phytophthora capsici but become resistant as they complete exponential growth. We previously demonstrated that ARR is associated with the fruit peel and identified gene expression and metabolomic changes potentially functioning as preformed defenses. ResultsHere, we compare the response to infection in fruit at resistant and susceptible ages using microscopy, quantitative bioassays, and weighted gene co-expression analyses. We observed strong transcriptional changes unique to resistant aged fruit 2-4 hours post inoculation (hpi). Microscopy and bioassays confirmed this early response, with evidence of pathogen death and infection failure as early as 4 hpi and cessation of pathogen growth by 8-10 hpi. Expression analyses identified candidate genes involved in conferring the rapid response including those encoding transcription factors, hormone signaling pathways, and defenses such as reactive oxygen species metabolism and phenylpropanoid biosynthesis. ConclusionThe early pathogen death and rapid defense response in resistant-aged fruit provide insight into potential mechanisms for ARR, implicating both pre-formed biochemical defenses and developmentally regulated capacity for pathogen recognition as key factors shaping age-related resistance.

plant biology↗

bioRxiv2017

QTLseqr: An R package for bulk segregant analysis with next-generation sequencing

1Next Generation Sequencing Bulk Segregant Analysis (NGS-BSA) is efficient in detecting quantitative trait loci (QTL). Despite the popularity of NGS-BSA and the R statistical platform, no R packages are currently available for NGS-BSA. We present QTLseqr, an R package for NGS-BSA that identifies QTL using two statistical approaches: QTL-seq and G. These approaches use a simulation method and a tricube smoothed G statistic, respectively, to identify and assess statistical significance of QTL. QTLseqr, can import and filter SNP data, calculate SNP distributions, relative allele frequencies, G values, and log10(p-values), enabling identification and plotting of QTL. The source code is available at https://github.com/bmansfeld/QTLseqr.\n\nCore ideasO_LIAn R package that performs Next Generation Sequencing Bulk Segregant Analysis was developed\nC_LIO_LITwo methods for analysis are provided: QTL-seq and G\nC_LIO_LIThe QTLseqr package is quick and produces publication quality figures and tables\nC_LI

genomics↗