Vanika Garg

The cultivated peanut is a crucial global legume crop that is essential for food security and nutrition, particularly in developing regions. However, its limited genetic variation hampers breeding progress and yield improvement. Here we constructed a graph-based pan-genome for peanut, incorporating 14 genomes that represent all 6 peanut varieties. Using this pan-genome, we genotyped 2,320 accessions, covering 88.03% of ICRISAT and 59.21% of USDA core germplasm, enriching valuable resources for genomic studies and breeding. We cataloged genomic structural variations and investigated the role of homoeologous exchanges in population divergence. Through our pan-genome approach, we overcame the challenges of genotyping posed by homoeologous exchanges and identified key genes associated with flowering and dwarfism in peanut. By integrating superior haplotypes and germplasm resources guided by the pan-genome, we further developed high-yield dwarf lines. This work provides essential genomic resources to accelerate functional gene discovery and modern peanut breeding.

Peanut ( Arachis hypogaea L.) is a globally significant leguminous oil crop. Here we present telomere-to-telomere genome assemblies for two diploid and four tetraploid peanut varieties, resulting in high-quality reference genomes, showing that the complex activities of transposable elements, chromosomal rearrangements and centromere expansions within subgenomes collectively contribute to the asymmetrical evolution of the tetraploid genome, and unique structural variants in the four tetraploid peanut varieties provide clear evidence of domestication. Population analyses of 521 peanut accessions revealed asymmetric selection events between subgenomes during breeding, and genome-wide association studies identified candidate genes linked to oil content, seed size and weight, kernel dehydration rate, and arachidic acid content. In addition, transcriptomic and metabolomic analyses revealed enhanced activity in lipidomic and anthocyanin biosynthetic pathways during seed development. These comprehensive findings provide insights into genome organization, evolutionary dynamics and phenotypic differentiation across peanut varieties that could inform future peanut breeding and improvement strategies.

Passion fruit ( Passiflora edulis ) is a highly nutritious horticultural crop cultivated widely across tropical and subtropical regions. Despite decades of breeding efforts that have led to the release of a few high‐yielding cultivars, on‐farm productivity remains suboptimal, and several existing cultivars are showing signs of declining vigor. To ensure the development of cultivars with stable and enhanced yields under both optimal and stress‐prone conditions, there is a growing impetus to improve breeding efficiency. Integrating advanced genomics technologies into conventional breeding pipelines offers a promising path forward. Over the past decade, substantial genomic resources have been developed, including genome‐wide markers, marker‐trait associations, reference genomes, and resequencing datasets. Some of these tools are already being deployed in breeding programs to enhance yield and consumer‐preferred traits. Emerging approaches such as genomic selection, speed breeding, and high‐throughput phenotyping hold further potential to accelerate genetic gains. Realizing the full benefits of these tools will require strategic utilization of diverse and targeted genetic resources, coupled with streamlined cultivar delivery systems. Addressing the technical and operational bottlenecks that hinder the translation of genomic advances to field‐ready cultivars will be key to securing the future of passion fruit improvement.

Accumulating evidences have shown that the mid-oleic fatty acid phenotype in peanuts cannot be explained by the traditional two-gene model involving AhFAD2A and AhFAD2B, which are genes encoding fatty-acid desaturase 2. But the underlying genetic mechanism remains unclear. Here, we present a population-specific pangenome using the eight founder genomes of the PeanutMAGIC population. This graph-based pangenome serves as a comprehensive reference, capturing all segregating haplotypes within the population. We conduct whole genome sequencing for the MAGIC Core, a subset of 310 RILs, for genotyping. Using pangenome-based genotypes, we trace recombination for detailed genomic analysis and phenotypic association. This investigation identifies a unique third gene, named AhFAD2C, near AhFAD2B. When recombination occurs, AhFAD2C segregates from AhFAD2B. We reveal the genotype determining mid-oleic fatty acid phenotype. Our findings underscore the limitations of a single-reference genome, which leads to false association and marker discovery. In contrast, a population-specific pangenome provides a more reliable framework for genomic studies. This study reveals insights into the genetic mechanism of peanut oil quality and demonstrates the advantages of population-specific pangenomes.

Yellow pitaya (Selenicereus megalanthus, 2n = 4x = 44) breeding remains severely hindered due to the lack of a reference genome. Here, we present a high-quality chromosome-level genome assembly of yellow pitaya using PacBio HiFi sequencing and Hi-C scaffolding technologies. We identify yellow pitaya as an autotetraploid with a genome size of 1.79 Gb, harboring 27,246 high-confidence genes probably from diploid ancestors, red pitaya (S. undatus). By comparative analysis of the 3D chromatin architecture, we identify varying number of compartment A/B, topologically associated domains (TADs), and structural variations in diploid (red pitaya) and polyploid (yellow pitaya) species. We find that TAD boundaries are enriched with transcription factor motifs in both species. We find significant alterations in expression of genes in the betalain biosynthesis pathway in both species. We detect differential expression of genes encoding key regulators of pericarp color within the TAD regions of polyploid pitaya and diploid pitaya. We also identify the expression differences in candidate genes that likely influence betacyanin and betaxanthin synthesis in both species. Our findings suggest that differential 3D genome organization, especially differences in TAD boundaries, may impact gene expression, which may further lead to different trait formation in different pitaya species. This provides theoretical implications for fast-forward breeding.

Crop wild relatives (CWRs) are invaluable for crop improvement. Among these, Hordeum I-genome species exhibit exceptional tolerance to alkali and salt stresses. Here we present a chromosome-scale genome assembly of Hordeum brevisubulatum (II, 2n = 2x =14) and genome resequencing of 38 diploid germplasms spanning 7 I-genome species. We reveal that the adaptive evolution of the H. brevisubulatum genome is shaped by structural variations, some of which may contribute to its adaptation to high alkali and salt environments. Evolutionary duplication of the stress sensor-responder module CaBP-NRT2 and the horizontally transferred fungal gene Fhb7 were identified as novel alkaline–saline tolerance mechanisms. We also demonstrate the potential of the Hordeum I genome in crop breeding through the newly synthesized hexaploid Tritordeum (AABBII) with enhanced alkaline–saline tolerance. Our study fills critical gaps in Hordeum genomics and CWR research, advancing introgression of CWR resources into current crops for sustainable agriculture.