Explore the vast range of titles available.

Background Millennia of directional human selection has reshaped the genomic architecture of cultivated cotton relative to wild counterparts, but we have limited understanding of the selective retention and fractionation of genomic components. Results We construct a comprehensive genomic variome based on 1961 cottons and identify 456 Mb and 357 Mb of sequence with domestication and improvement selection signals and 162 loci, 84 of which are novel, including 47 loci associated with 16 agronomic traits. Using pan-genome analyses, we identify 32,569 and 8851 non-reference genes lost from Gossypium hirsutum and Gossypium barbadense reference genomes respectively, of which 38.2% (39,278) and 14.2% (11,359) of genes exhibit presence/absence variation (PAV). We document the landscape of PAV selection accompanied by asymmetric gene gain and loss and identify 124 PAVs linked to favorable fiber quality and yield loci. Conclusions This variation repertoire points to genomic divergence during cotton domestication and improvement, which informs the characterization of favorable gene alleles for improved breeding practice using a pan-genome-based approach.

Alternative splicing (AS) is a crucial regulatory mechanism in eukaryotes, which acts by greatly increasing transcriptome diversity. The extent and complexity of AS has been revealed in model plants using high-throughput next-generation sequencing. However, this technique is less effective in accurately identifying transcript isoforms in polyploid species because of the high sequence similarity between coexisting subgenomes. Here we characterize AS in the polyploid species cotton. Using Pacific Biosciences single-molecule long-read isoform sequencing (Iso-Seq), we developed an integrated pipeline for Iso-Seq transcriptome data analysis (https://github.com/Nextomics/pipeline-for-isoseq). We identified 176 849 full-length transcript isoforms from 44 968 gene models and updated gene annotation. These data led us to identify 15 102 fibre-specific AS events and estimate that c. 51.4% of homoeologous genes produce divergent isoforms in each subgenome. We reveal that AS allows differential regulation of the same gene by miRNAs at the isoform level. We also show that nucleosome occupancy and DNA methylation play a role in defining exons at the chromatin level. This study provides new insights into the complexity and regulation of AS, and will enhance our understanding of AS in polyploid species. Our methodology for Iso-Seq data analysis will be a useful reference for the study of AS in other species.

Phenotypic diversity and evolutionary innovation ultimately trace to variation in genomic sequence and rewiring of regulatory networks. Here, we constructed a pan-genome of the Gossypium genus using ten representative diploid genomes. We document the genomic evolutionary history and the impact of lineage-specific transposon amplification on differential genome composition. The pan-3D genome reveals evolutionary connections between transposon-driven genome size variation and both higher-order chromatin structure reorganization and the rewiring of chromatin interactome. We linked changes in chromatin structures to phenotypic differences in cotton fiber and identified regulatory variations that decode the genetic basis of fiber length, the latter enabled by sequencing 1,005 transcriptomes during fiber development. We showcase how pan-genomic, pan-3D genomic and genetic regulatory data serve as a resource for delineating the evolutionary basis of spinnable cotton fiber. Our work provides insights into the evolution of genome organization and regulation and will inform cotton improvement by enabling regulome-based approaches. Pan-genome and pan-3D genome analyses of the Gossypium genus reveal evolutionary relationships among transposon-driven genome expansion and chromatin topology innovation and regulatory variations for cotton fiber development.

Although epigenetic modification has long been recognized as a vital force influencing gene regulation in plants, the dynamics of chromatin structure implicated in the intertwined transcriptional regulation of duplicated genes in polyploids have yet to be understood. Here, we document the dynamic organization of chromatin structure in two subgenomes of allotetraploid cotton ( Gossypium hirsutum ) by generating 3D genomic, epigenomic and transcriptomic datasets from 12 major tissues/developmental stages covering the life cycle. We systematically identify a subset of genes that are closely associated with specific tissue functions. Interestingly, these genes exhibit not only higher tissue specificity but also a more pronounced homoeologous bias. We comprehensively elucidate the intricate process of subgenomic collaboration and divergence across various tissues. A comparison among subgenomes in the 12 tissues reveals widespread differences in the reorganization of 3D genome structures, with the Dt subgenome exhibiting a higher extent of dynamic chromatin status than the At subgenome. Moreover, we construct a comprehensive atlas of putative functional genome elements and discover that 37 cis -regulatory elements (CREs) have selection signals acquired during domestication and improvement. These data and analyses are publicly available to the research community through a web portal. In summary, this study provides abundant resources and depicts the regulatory architecture of the genome, which thereby facilitates the understanding of biological processes and guides cotton breeding. This study describes comprehensive dynamic divergence of subgenomes in allotetraploid cotton, with an focus on cis-regulatory elements and 3D genomic architecture at 12 major tissues/developmental stages throughout the life cycle.

Background Despite remarkable advances in our knowledge of epigenetically mediated transcriptional programming of cell differentiation in plants, little is known about chromatin topology and its functional implications in this process. Results To interrogate its significance, we establish the dynamic three-dimensional (3D) genome architecture of the allotetraploid cotton fiber, representing a typical single cell undergoing staged development in plants. We show that the subgenome-relayed switching of the chromatin compartment from active to inactive is coupled with the silencing of developmentally repressed genes, pinpointing subgenome-coordinated contribution to fiber development. We identify 10,571 topologically associating domain-like (TAD-like) structures, of which 25.6% are specifically organized in different stages and 75.23% are subject to partition or fusion between two subgenomes. Notably, dissolution of intricate TAD-like structure cliques showing long-range interactions represents a prominent characteristic at the later developmental stage. Dynamic chromatin loops are found to mediate the rewiring of gene regulatory networks that exhibit a significant difference between the two subgenomes, implicating expression bias of homologous genes. Conclusions This study sheds light on the spatial-temporal asymmetric chromatin structures of two subgenomes in the cotton fiber and offers a new insight into the regulatory orchestration of cell differentiation in plants.

Background DNA methylation is a crucial epigenetic modification, which is involved in many biological processes, including gene expression regulation, embryonic development, cell differentiation and genomic imprinting etc. And it also involves many key regulatory genes in eukaryotes. By tracing the evolutionary history of methylation-related genes, we can understand the origin and expansion time of these genes, which helps to understand the evolutionary history of plants, and we can also understand the changes of DNA methylation patterns in different species. However, most studies on the evolution of methylation-related genes failed to be carried out for the whole DNA methylation pathway. Results In this study, we conducted a comprehensive identification of 33 methylation-related genes in 77 species, and investigated gene origin and evolution throughout the plant kingdom. We found that the origin of genes responsible for methylation maintenance and demethylation evolved early, while most de novo methylation-related genes appeared late. The methylation-related genes were expanded by whole genome duplication and tandem replication, but were also accompanied by a large number of gene absence events in different species. The gene length and intron length varied a lot in different species, but exon structure and functional domains were relatively conserved. The phylogenetic relationships of methylation-related genes were traced to reveal the evolution history of DNA methylation in different species. The expression patterns of methylation-related genes have changed during the evolution of species, and the expression patterns of these genes in different species can be clustered into four categories. Conclusions The study describes a global characterization of DNA methylation-related genes in the plant kingdom. The similarities and differences in origin time, gene structure and phylogenetic relationship of these genes lead us to understand the evolutionary conservation and dynamics of DNA methylation in plants.

Background Cotton is a major world cash crop and an important source of natural fiber, oil, and protein. Drought stress is becoming a restrictive factor affecting cotton production. To facilitate the development of drought-tolerant cotton varieties, it is necessary to study the molecular mechanism of drought stress response by exploring key drought-resistant genes and related regulatory factors. Results In this study, two cotton varieties, ZY007 (drought-sensitive) and ZY168 (drought-tolerant), showing obvious phenotypic differences under drought stress, were selected. A total of 25,898 drought-induced genes were identified, exhibiting significant enrichment in pathways related to plant stress responses. Under drought induction, A t subgenome expression bias was observed at the whole-genome level, which may be due to stronger inhibition of D t subgenome expression. A gene co-expression module that was significantly associated with drought resistance was identified. About 90% of topologically associating domain (TAD) boundaries were stable, and 6613 TAD variation events were identified between the two varieties under drought. We identified 92 genes in ZY007 and 98 in ZY168 related to chromatin 3D structural variation and induced by drought stress. These genes are closely linked to the cotton response to drought stress through canonical hormone-responsive pathways, modulation of kinase and phosphatase activities, facilitation of calcium ion transport, and other related molecular mechanisms. Conclusions These results lay a foundation for elucidating the molecular mechanism of the cotton drought response and provide important regulatory locus and gene resources for the future molecular breeding of drought-resistant cotton varieties.

Cotton, a globally vital crop, faces severe yield losses due to heat‐induced male sterility. To decipher the thermotolerance mechanisms, we conducted multi‐omics analyses (3D chromatin architecture, transcriptome, and epigenome profiling) on heat‐tolerant (84021) and heat‐sensitive (H05) lines across critical anther developmental stages. We identified subgenome homoeologous gene expression bias linked to thermotolerance, driven by high temperature (HT)‐induced dynamic chromatin topology reorganization. The sensitive line exhibited aberrant 3D structural hyperactivation during anther dehiscence, causing deleterious gene overexpression. Central to this regulation is GhAL5, an Alfin‐like transcription factor modulated through chromatin loop dynamics and TAD‐like boundary reorganization under heat stress. Functional studies confirmed the pivotal role of GhAL5: overexpression enhanced thermotolerance, while RNAi/CRISPR lines showed compromised heat resilience. Remarkably, GhAL5 conferred cross‐species heat protection when expressed in rice. Mechanistically, GhAL5 potentially orchestrates male thermotolerance through bidirectional chromatin structure modulation. This study establishes 3D genome plasticity and chromatin remodeling as key drivers of plant thermal adaptation, proposing chromatin‐aware breeding strategies for climate‐resilient crops. This study investigates cotton’s high‐temperature (HT) response using multi‑omics. Dynamic 3D genome changes drive expression bias affecting male fertility. The tolerant line shows controlled chromatin dynamics, while the sensitive line exhibits overactivation. A key chromatin‑regulated gene, GhAL5, enhances thermotolerance when overexpressed in different crops, revealing genomic HT‑adaptation mechanisms and cross‑species potential for breeding heat‑resilient crops.

The pan-Shennongjia region represents a globally significant biodiversity hotspot characterized by high species diversity and endemism. While its rich medicinal resources have long been recognized, the systematic characterization of their natural components and therapeutic potential remains underexplored. Here, we integrated 405 representative biological species from the pan-Shennongjia region, corresponding to 323 traditional Chinese medicine materials, into a Chinese genus-species level phylogenetic tree. We identified clade-specific species enrichments at the family level within this region. Notably, case studies of Chrysanthemum indicum var. aromaticum and Dendrobium flexicaule and Chrysanthemum indicum var. aromaticum revealed specificized accumulations of polysaccharides and volatile terpenoids, respectively, suggesting an environmentally-driven adaptive diversification of metabolomic profiles in pan-Shennongjia herbs. To comprehensively characterize this, we constructed a pan-Shennongjia Herbs Multi-Omics Components (SHMC) database, integrating over 20 million diverse omics-based molecules including small RNAs, small peptides, secondary metabolites, and carbohydrates. Analysis of the components distribution patterns across species revealed phylogenetic selectivity. To validate the accuracy of the annotated components, we systematically analyzed secondary metabolites and small RNAs in Coptis chinensis , and small peptides in Scolopendra subspinipes mutilans based on additional transcriptomic and metabolomic data, and further evaluated their therapeutic potential. This study establishes a crucial foundation for the conservation and sustainable utilization of pan-Shennongjia’s medicinal resources, offering the first regional-scale omics-based component database for mining valuable natural products.

Eukaryotic genomes are highly folded for packing into higher-order chromatin structures in the nucleus. With the emergence of state-of-the-art chromosome conformation capture methods and microscopic imaging techniques, the spatial organization of chromatin and its functional implications have been interrogated. Our knowledge of 3D chromatin organization in plants has improved dramatically in the past few years, building on the early advances in animal systems. Here, we review recent advances in 3D genome mapping approaches, our understanding of the sophisticated organization of spatial structures, and the application of 3D genomic principles in plants. We also discuss directions for future developments in 3D genomics in plants.