Land plants underpin civilization and planetary health, yet their genomic diversity remains largely uncharted. Current resources are unstandardized and scarce, lacking reference genomes for 95% of genera, 70% of families, and 51% of orders, impeding evolutionary and functional insight. We thus propose the PLANeT initiative, an international effort to generate high-quality, standardized genomes across the plant tree of life. Integrating artificial intelligence (AI) with genomics, we will decode conserved principles to advance fundamental plant biology, biodiversity conservation, crop improvement, and natural product discovery. Engaging around 100 labs to train 1,000 scientists, we will tackle pivotal questions for a sustainable future.

Abstract Bacterial communities and the bacteriophages infecting them are the basis of every ecosystem, including holobionts. The various ways in which these microorganisms interact with each other in complex communities over the life of the host affects the holobiont fitness. Despite being ubiquitous and environmentally relevant, plant-associated microbial communities remain understudied, especially in the phyllosphere, mainly because of the low abundance of microbes and the complexity of the system. In this work we followed bacteria and phage community dynamics in the phyllosphere over a growing cycle of Arabidopsis thaliana , to understand the ecology and relevance of bacteriophages in complex bacterial communities. We focused on Pseudomonas , a common plant pathogen and commensal, and the phages infecting them, in three setups of increasing complexity: in vitro, controlled experiments in planta and in wild populations of A. thaliana . We found that bacterial communities are resilient to phage infection, and more dynamic than the phages infecting them over the growing season, suggesting that although ubiquitous and abundant, bacteriophages exert selective pressures on leaf bacterial communities only intermittently.

DNA methylation is a conserved epigenetic modification crucial for silencing genes and transposable elements (TEs). However, the mechanisms that cause silencing remain unclear, partly because methyl reader protein mutants in both plants and animals show minimal transcriptional changes. To explore the possibility of redundancy among these silencing mechanisms, we generated combinatorial mutants of H1.1, H1.2, ADCP1, MOM1, MBD2, MBD5, and MBD6 lacking key methyl readers and related silencing pathways. We observed massive derepression of genes and TEs at DNA-methylated loci, showing that these pathways account for 73% of silencing compared to DNA methylation-free mutants. We also observed that immune response genes were upregulated, causing an imbalance between growth and defense. Loss of downstream silencing pathways further disrupted 3D genome organization, leading to increased euchromatin-heterochromatin interactions. These findings highlight the cooperative action of multiple downstream mechanisms in DNA methylation-mediated silencing and genome organization.

The microbiome often protects plants against pathogens, but most findings are limited to controlled experiments in the lab. In the context of wild populations, one key challenge is to understand sources of variation that impact the commensal microbiome, which in turn shapes the degree of protection. Here, we surveyed both disease symptoms and microbiomes from wild populations of Arabidopsis thaliana over four consecutive seasons (Autumn/Spring) across three different land use types. Land use types varied in the extent of anthropogenic influences and included forest meadows, human-impacted fields adjacent to agriculture or municipal parks and highly disturbed habitats near railroad tracks. By building an integrative map of abiotic and biotic variables, we find that a key predictor of disease was biodiversity across ecological scales. Plant communities with higher diversity were associated with increased microbial diversity and reduced disease burden in A. thaliana populations, particularly in the Spring. However, the diversity-microbiome-disease relationships were all sensitive to season and further modulated by land use. Taken together, our work highlights the importance of anthropogenic change reshaping species interactions across ecological scales to impact disease risk in wild plant populations. This article is part of the theme issue 'Wild plant pathosystems'.

In plants, multiple cell types contribute to immunity, but what division of labor exists among cell types when immunity is activated? We compared, at single-cell resolution, the response of Arabidopsis thaliana leaf cells during pattern-triggered and effector-triggered immunity (PTI/ETI), sampled at 3 and 5 h after infection with Pseudomonas syringae DC3000. Core defense modules were broadly shared across cell clusters, but their activation varied in timing and intensity, with key immune receptors also showing cell type-specific expression dynamics. Mesophyll cell populations could be distinguished based on their resilience patterns: after the initial response, some populations continue to express defense genes at high levels during both PTI and ETI, while others quickly reinitiate growth-related gene expression programs but only during PTI. Gene regulatory network inference revealed WRKY-regulated modules enriched in cells sensing effectors, while salicylic acid biosynthesis regulators were activated in complementary clusters. Analysis of cue1 mutants demonstrated that core immune responses are robust to altered leaf architecture. In addition, we uncovered cryptic defense pathways, including sucrose-responsive modules, in this mutant. By capturing early immune responses at high resolution, our study reveals cell type-specific coordination of plant immunity and provides a framework for decoding immune signaling networks.

Plants and their pathogens coevolve over long time periods, and the history of coevolution is recorded in plant genes that confer pathogen resistance (many coding for nucleotide-binding leucine-rich repeat proteins, NLRs). Advances in the ability to sequence genomes from many different species as well as many genomes from the same species reveal that 1) the number of NLR genes differs widely between species and 2) NLR genes may exhibit extensive nucleotide variation as well as presence/absence polymorphism within species. In the light of the latest insights into the genomic features associated with NLR gene diversity, we aim here to evaluate the contribution of forces involved in NLR gene family evolution: mutation, recombination, gene duplication and deletion and natural selection. We highlight novel combinations of population genomics methods and statistics that can provide an improved framework for describing NLR gene family evolution in the genome space.

Eukaryotic centromeres mediate chromosome segregation during cell division. Plant centromeres are loaded with CENH3-variant nucleosomes, which direct kinetochore formation and spindle-microtubule interaction. Centromeres are frequently composed of megabase-scale satellite repeat arrays, or retrotransposon nests. In monocentric genomes, such as the model plant Arabidopsis thaliana, pericentromeric heterochromatin surrounds the CENH3-occupied satellite arrays. A zone of suppressed meiotic crossover recombination contains the centromere and extends into the pericentromeres. Here, we explore how natural variation in Arabidopsis influences centromere-proximal crossover frequency and segregation distortion when centromeres are heterozygous. We used fluorescent crossover reporters to quantify the effect of genetic variation on centromere-proximal recombination in 12 F1 hybrids between the reference strain Col-0 and nonreference accessions that captured Eurasian and relict diversity, and in total, we measured 3,037,802 meioses. The majority of the F1 hybrids (49 of 60) had significantly higher or lower centromere-proximal crossover frequency than inbreds. We relate hybrid crossover frequencies to patterns of nucleotide diversity and centromeric structural variation, and in a subset of 7 accessions, to epigenetic patterns of CENH3 enrichment and DNA methylation. Using linear modeling, we observed that chromosome and accession, and their interaction, together explained 85% of variation in crossover frequency, consistent with cis- and trans-acting modifying effects. The fluorescent reporters also allow segregation distortion through meiosis to be quantified between hybrids and inbreds. We observed a minority of hybrids (18 of 60) with distorted segregation through meiosis compared to inbreds, which occurred with or without a simultaneous change to centromere-proximal crossover frequency. Linear modeling revealed that 56% of variation in segregation distortion is explained by chromosome and accession, but with a stronger effect of accession compared to crossover frequency. We discuss how Arabidopsis centromeric structural heterozygosity may modify recombination and cause segregation distortion through meiosis.

Climate change forces species to adapt rapidly to avoid extinction. To directly observe rapid adaptation and extinction, we conducted synchronized evolution experiments with Arabidopsis thaliana in 30 locations across Western Europe, the Mediterranean, the Levant, and North America. Whole-genome pooled sequencing of ~70,000 surviving plants revealed repeatable allele frequency shifts in similar climates but divergent shifts across contrasting ones, indicating evolutionary adaptation. We identified genetic variants linked to climate adaptation, including genes involved in processes ranging from thermal-stress sensing to spring-flowering timing. Evolutionary trends were often predictable, but variable, across environments. In warmer climates, evolutionary predictability correlated with population survival over 5 years, whereas erratic changes preceded extinction. These results show that rapid climate adaptation is possible, but understanding its limits will be crucial for biodiversity forecasting.

The long-standing notion that genotypes map to phenotypes through simple one gene-one trait relationships continues to shape both research in the life sciences and public understanding, with implications for policy and funding priorities. Yet this paradigm is increasingly recognized as inadequate for explaining continuous phenotypic variation and the complex genetic architectures of the genotype-phenotype map. Modern genetics emerged from the early 20th-century synthesis of Mendelian and biometric schools of heredity, with R.A. Fisher demonstrating early on how multiple discrete loci could collectively produce continuous variation. Despite this fundamental insight, Mendelism-with its focus on single genes and standardized genetic backgrounds-became the dominant framework, shaping current genetics research and molecular biology as well as science education. The advent of large-scale genomic data has revealed yet again the limitations of this reductionist approach. Evidence from quantitative genetics now shows that most phenotypes arise from complex networks of many interdependent genes and their dynamic responses to environmental perturbations. Here we trace the historical roots of how Mendelian classical genetics departed from the biometric school to create the current predominant paradigm in genetics, despite fundamentally unresolved issues. Moving on from this one-sided paradigm will require systematic development of integrative, evolutionarily grounded experimental approaches that better capture the multigenic and context-dependent nature of inheritance. Achieving such an extended perspective will require methodological innovation, including advances in large-scale (e.g. automated) phenotyping. Dedicated research programs will be necessary to advance a new era of genetic research into the complex mechanisms underlying phenotypic variation.

The mechanisms underlying the emergence of new DNA repeat classes remain poorly understood. One such example is the formation of interstitial telomeric repeat (ITR) domains commonly viewed as telomere-fossil byproducts of chromosome rearrangements. Here, we report that in Arabidopsis thaliana , ITRs arise from centromeres as centromeric-telomeric mosaic satellites that expand into higher-order structures via in situ amplification. Long-read sequencing of mutation accumulation lines and forward simulations of mutational processes confirmed the propensity of centromeres to form telomeric motifs. During establishment, ITRs adopt an atypical chromatin state that excludes CENH3 incorporation, thereby enabling escape from the functional constraints of centromere identity. Accordingly, a pangenomic survey of natural accessions showed that ITRs vary abruptly and independently of telomere length, notably through transposon-associated block duplications. These findings identify centromeres as major sources of telomeric sequences and an original route for the emergence of new DNA satellite types.

Because grapevine (Vitis vinifera L.) cultivars are highly heterozygous, they must be clonally propagated to preserve their varietal attributes. Over extended cultivar propagation, somatic mutations arise and can generate new phenotypes useful for intra-varietal improvement. Somatic variants with looser bunches – associated with more uniform berry ripening and reduced bunch rot incidence – are particularly valuable in compact-bunch cultivars. To understand the basis of this trait, we combined phenotyping, genomics, and genetic analyses to study VP11, a loose-bunch somatic variant clone with reduced fruit set of the wine grape cultivar ‘Tempranillo Tinto’. Pollen viability and the number of seeds per berry were reduced by 50

Specialized or secondary metabolites mediate biotic interactions, including virulence and defense. In plant-pathogenic Pseudomonas, certain specialized metabolites can enhance colonization of plant hosts, yet their broader contribution to plant-microbe interactions and the relative importance of different metabolites remain unclear. Specialized metabolites are products of enzymes encoded in biosynthetic gene clusters (BGCs), whose prediction from genome sequences has become routine but whose functional roles are rarely tested experimentally. Here, we characterize the BGC repertoire of 225 P. viridiflava isolates from Arabidopsis thaliana and assess BGC contributions to fitness and disease severity in planta. The BGC landscape of P. viridiflava was dominated by non-ribosomal peptide synthetase (NRPS) and NRPS-like BGCs, which accounted for 50% of the predicted BGCs. One-third of the BGC families were restricted to a single isolate. Transposon mutagenesis coupled with random barcode transposon sequencing (RB-TnSeq) revealed that the majority of BGCs reduce rather than increase fitness during A. thaliana infection, with the magnitude of the fitness cost varying across host genotypes. This cost could be due to exploitation of public goods by cheater mutant strains. In single-isolate plant infections, where public goods are not available, we found 11/34 BGC families correlated with disease severity. Yet, only two of these (an N-acetylglutaminylglutamine amide [NAGGN] and an NRPS) were negatively associated with disease severity, which is positively correlated with bacterial growth in this pathosystem, further indicating that BGCs are generally not beneficial in planta. Our findings reveal extensive and largely uncharacterized biosynthetic potential in populations of P. viridiflava and indicate that candidate metabolites are likely not adaptive for direct interactions with the plant, but perhaps for microbe-microbe interactions either in planta or in other ecological niches. IMPORTANCE:Bacteria, including plant-associated bacteria such as Pseudomonas viridiflava, produce a vast array of chemical compounds, called secondary or specialized metabolites, that can mediate their interaction with the plant host or other microorganisms. Some of these compounds are known to directly influence how bacteria interact with plants, but it has been unclear whether this is a general rule. We studied a large collection of closely related leaf-dwelling P. viridiflava-a plant pathogen-that varied in their ability to cause disease. We found that very few of the gene clusters responsible for making specialized metabolites improved the ability of the bacteria to colonize its natural host Arabidopsis thaliana. On the contrary, carrying these gene clusters often reduced bacterial growth and disease severity in plants. Specialized metabolites may instead primarily be important for interacting with other microbes, different host species, or under environmental conditions we did not test. These are questions that remain for future research.

Abstract Premise Third‐generation sequencing has revolutionized genomics, enabling in‐depth analysis of genome sequence, structure, and epigenetic features. Yet, extracting high‐quality DNA for long‐read sequencing remains a bottleneck—particularly in non‐model plants, such as mature trees growing in natural environments, which often contain abundant endogenous compounds that hinder extraction and downstream applications. Methods and Results We developed an optimized, robust, and cost‐effective DNA extraction protocol that yields high‐quality DNA suitable for Oxford Nanopore Technologies and PacBio sequencing. Validation across diverse taxa—including six Nothofagus species, gymnosperms endemic to Andean–Patagonian forests, exotic conifers of commercial value, and model plants—demonstrated consistently high DNA purity (A 260 /A 280 > 1.8, A 260 /A 230 > 2.0) and fragment sizes ≥30 kbp. Downstream sequencing confirmed suitability for applications requiring long, intact molecules and base modification detection. Conclusions Compared to commercial kits and standard protocols, this approach achieved superior DNA integrity and yield without specialized equipment, offering an accessible solution for researchers working with challenging plant species.