Biology subjects

Murray, E. R.

Publications and source records attributed to Murray, E. R..

5 recordsLinked to original sources

bioRxiv2025

Pangenome of U.S. ex-PVP and Wild Sorghum Reveals Structural Variants and Selective Sweeps Shaping Adaptation and Trait Improvement

Sorghum is a cereal crop grown for food, feed, and biofuel, yet the genomic diversity of elite commercial lines remains underexplored. Here, we assembled a sorghum pangenome from long-read sequences of 46 U.S. ex-Plant Variety Protection Act (ex-PVP) cultivars and a haplotype-resolved assembly of one wild accession. The pangenome revealed largely conserved genomic architecture across elite lines but identified presence-absence variations (PAVs) in 28% of gene families, including genes involved in stress responses and starch metabolism, such as STARCH BRANCHING ENZYME I (SBE1). Selective sweep analyses detected strong signals at key flowering-time loci (Ma1/SbPRR37, Ma2, Ma6) and circadian/light regulators (PHOT1, DET1, XAP5), with PHYA showing copy number variations (CNVs). Analysis of 24 wild accessions, beyond the core pangenome panel, detected CNVs in MULTIDRUG AND TOXIC COMPOUND EXTRUSION (MATE) transporters, potentially reflecting selection or breeding for enhanced herbicide detoxification. These results highlight breeding-shaped regions and position the pangenome as a resource for sorghum improvement.

genomics↗

bioRxiv2025

Transcriptomic stress responses in Vaccinium spp. F1 hybrids: Implications for temperature-resilient cranberry breeding using a crop wild relative

O_LICranberry (Vaccinium macrocarpon) is an important North American fruit crop with vulnerability to temperature extremes and a relatively recent domestication history. Hybridization with a cold-adapted crop wild relative (CWR), V. oxycoccos, offers a strategy for improving temperature stress tolerance. C_LIO_LIWe conducted RNA sequencing (RNA-seq) on V. macrocarpon and F1 hybrids between V. macrocarpon and V. oxycoccos subjected to acute heat and cold stress, capturing early transcriptional responses up to 30 minutes (heat) and 95 minutes (cold) after treatment onset. We then evaluated differences in responses across genotypes and stress conditions. C_LIO_LIDifferential expression analysis and functional profiling revealed cold-induced differences in pathways related to photosynthesis, ribosomes, defense, and hormone signaling. No subgenome-specific functional specialization was observed. Two F1 hybrids exhibited suggestive cold resilience, with expression changes elevated at 60 minutes but declining by 95 minutes. Hybrids also displayed substantial regulatory variation under stress and transgressive downregulation of photosynthesis genes under ambient conditions. C_LIO_LIThese findings suggest that V. oxycoccos introgression could be utilized in breeding cold-tolerant cranberry cultivars. Variation observed between F1 hybrids reflects the diversity introduced through CWR germplasm and provides opportunities for selection. Conservation of V. oxycoccos and other CWRs remains critical for future crop improvement. C_LI Plain Language SummaryCranberries face increasing threats from temperature extremes. We explored crossbreeding cultivated cranberry (Vaccinium macrocarpon) and a cold-adapted wild relative (V. oxycoccos) to improve resilience to temperature stress. Hybrids showed different gene expression patterns from their parents, especially under cold stress. Our findings support the value of wild relatives in crop improvement and emphasize the importance of protecting wild plant diversity.

plant biology↗

bioRxiv2024

Soil depth determines the microbial communities in Sorghum bicolor fields

Sorghum bicolor, an important global crop, adapted to thrive in hotter and drier conditions than maize or rice, has deep roots that interact with a unique and stratified soil microbiome that plays a crucial role in plant health, growth, and carbon storage. Microbiome studies on agricultural soils, particularly fields growing S. bicolor, have been mostly limited to surface soils (<30 cm). Here we investigated the abiotic factors of soil properties, field location, depth, and the biotic factors of sorghum type across 38 genotypes on the soil microbiome. Utilizing 16S rRNA gene amplicon sequencing, our analysis reveals significant changes in microbial composition and decreasing diversity at increasing soil depths within S. bicolor regardless of genotype or fields. Notably, specific microbial families, such as Thermogemmatisporaceae and an unclassified family within the ABS-6 order, were enriched in deeper soil layers beyond 30 cm. Additionally, microbial richness and diversity declined with depth, reaching a minimum at the 60 - 90 cm layer, with layers beyond 90 cm increasing in alpha diversity. These findings highlight the importance of soil depth in agricultural soil microbiome studies.

microbiology↗

bioRxiv2024

Domesticated cannabinoid synthases amid a wild mosaic cannabis pangenome

Cannabis sativa is a globally significant seed-oil, fiber, and drug-producing plant species. However, a century of prohibition has severely restricted legal breeding and germplasm resource development, leaving potential hemp-based nutritional and fiber applications unrealized. Existing cultivars are highly heterozygous and lack competitiveness in the overall fiber and grain markets, relegating hemp to less than 200,000 hectares globally1. The relaxation of drug laws in recent decades has generated widespread interest in expanding and reincorporating cannabis into agricultural systems, but progress has been impeded by the limited understanding of genomics and breeding potential. No studies to date have examined the genomic diversity and evolution of cannabis populations using haplotype-resolved, chromosome-scale assemblies from publicly available germplasm. Here we present a cannabis pangenome, constructed with 181 new and 12 previously released genomes from a total of 156 biological samples from both male (XY) and female (XX) plants, including 42 trio phased and 36 haplotype-resolved, chromosome-scale assemblies. We discovered widespread regions of the cannabis pangenome that are surprisingly diverse for a single species, with high levels of genetic and structural variation, and propose a novel population structure and hybridization history. Conversely, the cannabinoid synthase genes contain very low levels of diversity, despite being embedded within a variable region containing multiple pseudogenized paralogs and distinct transposable element arrangements. Additionally, we identified variants of acyl-lipid thioesterase (ALT) genes2 that are associated with fatty acid chain length variation and the production of the rare cannabinoids, tetrahydrocannabinol varin (THCV) and cannabidiol varin (CBDV). We conclude the Cannabis sativa gene pool has only been partially characterized, and that the existence of wild relatives in Asia remains likely, while its potential as a crop species remains largely unrealized.

plant biology↗

bioRxiv2023

Generating high quality reference genomes from field collected specimens by optimizing preservation

Sample preservation challenges efforts to generate high-quality reference genomes or pangenomes for all 2 million+ plant and animal species. Here we show 95% ethanol protects against degradation for fish blood (22{degrees}C, [≤]6 weeks) and plant tissue (4{degrees}C, [≤]3 weeks). Using Nanopore, we assemble high quality reference genomes from three fish and two plant species (contig N50: 6.5-13.8Mb; BUSCO completeness: 94.4-99.2%; QV: 43.8 for M. esculenta).

genomics↗