Random motility regulation as a generic mechanism of community formation 

Dinelli et al., 2026

The self-organization of microbial ecosystems involves a large variety of mechanisms, ranging from biochemical signaling to population dynamics. Among these, the role of motility regulation has been little studied, despite the importance of active migration processes. Here we show how weak, random motility regulation suffices to induce complex forms of organization in bacterial mixtures comprising a large number of coexisting strains. First, we simulate microscopic models of run-and-tumble bacteria whose self-propulsion speeds are weakly regulated by the local density of each strain, mimicking the impact of weak, random metabolic interactions. Our simulations reveal that, as the heterogeneity of the interaction network increases, the system undergoes a phase transition leading to the emergence of distinct, spatially segregated communities. To account for these results and assess their robustness, we use random-matrix theory to analyze the hydrodynamic description of the bacterial mixture, obtaining a quantitative agreement with our microscopic simulations. Our results hold for a variety of motility-regulation mechanisms and highlight the need to characterize the role of motility regulation in experimentally relevant situations.

https://journals.aps.org/pre/abstract/10.1103/cl1f-mfgp

PrePrint:

https://arxiv.org/abs/2503.12692

The host–microbiome dimension of ecological regime shifts 

Rindi et al., 2026

Regime-shift research has largely overlooked host-associated microbiomes, even though they can buffer stress, speed recovery, and mediate chemical interactions that sustain reinforcing feedbacks and lock in alternative states.

Host–microbiome partnerships bolster stress-tolerance to perturbations and support recovery across marine foundation species.

Combining innovative microbiome manipulations with regime-shift mapping tools can reveal whether altering microbiomes shifts thresholds.

Host-associated microbiome-based indicators may precede host-based metrics and enable earlier, more targeted interventions.

A holobiont lens on regime-shift dynamics may help translate microbiome-assisted restoration into actionable tools for managing ecosystems under accelerating change.

Rising climate and local pressures increase the risk of regime shifts, yet despite progress, thresholds remain difficult to identify early enough to take action. We argue that this shortfall reflects a host-centric view that largely omits host-associated microbiomes, which can shape resilience by modulating stress tolerance, aiding recovery, and stabilizing alternative states through inhibitory chemical interactions. We propose a research agenda that integrates host-associated microbiomes into regime-shift ecology by combining novel microbiome manipulations in laboratory and field settings with regime-shift mapping tools, while simultaneously developing microbiome-based early warning indicators. Reframing regime-shift theory through a host-associated microbiome lens can provide practical tools to anticipate collapse, improve monitoring, and inform timely interventions, thereby supporting more adaptive and robust conservation under accelerating global change.

https://www.cell.com/trends/ecology-evolution/abstract/S0169-5347(26)00148-5

Environmental microbes as modulators of plant volatile landscapes: Implications for plant–insect chemical communication 

Zhang et al., 2026

Free-living environmental microbes at four plant-atmosphere interfaces (leaf, nectar, fruit, and bark surfaces) intercept, biotransform, and augment plant volatile signals, shaping what herbivores, pollinators, and parasitoids detect. This forum article reviews how microbes remodel these signals, the threats posed by climate change and land-use intensification, and priorities for translating microbial volatile ecology into sustainable pest management.

The global phyllosphere spans an estimated 1 billion square kilometres of above-ground plant surface, placing surface-dwelling epiphytes, carposphere colonisers, and nectar inhabitants at the plant-atmosphere boundary. At the plant-atmosphere interface, these microbes occupy a biochemical gatekeeper role: intercepting, consuming, and transforming plant-emitted volatile organic compounds (VOCs) before those signals reach insect receivers. Isoprene monooxygenases in Rhodococcus and Variovorax catalyse the oxidation and biocapture of isoprene emitted from leaf surfaces, while fungal cytochrome P450 monooxygenases, reductases, and Baeyer–Villiger oxidases execute stereoselective biotransformations, including regioselective hydroxylation of inactivated C–-H bonds, enantioselective carbonyl reduction, and lactone-forming oxidations.

Biotransformation can redirect a plant monoterpene into functionally divergent chemical spaces. For example, Aspergillus niger DSM 821 and Corynespora cassiicola DSM 62475 can convert (±)-linalool into furanoid and pyranoid linalool oxides, while A. niger DSM 821 and Botrytis cinerea additionally produce lilac aldehydes and lilac alcohols as byproducts through a pathway postulated to proceed via 8-hydroxylinalool. Furanoid linalool oxide is electroantennographically active in bee pollinators and attracts hoverflies, while lilac aldehyde acts as a repellent to the same hoverfly species. Thus, fungal biotransformations can generate compounds with opposing semiochemical functions within the same receiver community. Plant VOCs, in turn, shape phyllosphere microbial community composition, establishing bidirectional exchanges with direct consequences for herbivore, pollinator, and parasitoid perception.

linkinghub.elsevier.com/retrieve/pii/S0966842X26001605

Metarhizium – Insect Interactions: Implications for Nitrogen Cycling

Tang et al., 2026

Los hongos endófitos entomopatógenos desempeñan un doble papel ecológico como mutualistas de las plantas y patógenos de insectos. A través de esta doble función, transfieren a las plantas nitrógeno derivado de los insectos, contribuyendo de manera significativa al ciclo del nitrógeno en los ecosistemas. Sin embargo, los mecanismos que regulan esta transferencia han permanecido poco explorados.

En este estudio, los autores demuestran que el consorcio planta-hongo formado por la especie ampliamente distribuida Metarhizium robertsii constituye un modelo idóneo para comprender la biología y el funcionamiento ecológico de los hongos endófitos entomopatógenos. Los resultados muestran que este hongo es capaz de degradar la caulilexina C, un compuesto antifúngico producido por las raíces de las plantas, generando como producto el compuesto volátil 1-metoxiindol, cuya función ecológica no había sido descrita previamente.

El 1-metoxiindol actúa como un potente atrayente de insectos. En particular, es detectado por el receptor olfativo Or74a de las larvas de Drosophila melanogaster y atrae a diversas especies de dípteros hacia el sistema planta-Metarhizium. Una vez reclutados, estos insectos son infectados y consumidos por el hongo, lo que incrementa la transferencia de nitrógeno derivado de los insectos hacia las plantas asociadas.

Estos hallazgos revelan un mecanismo ecológico auto-reforzante que integra la química vegetal, el metabolismo fúngico y el comportamiento de los insectos. Este proceso fortalece la simbiosis planta-hongo y constituye una vía previamente desconocida mediante la cual los hongos endófitos entomopatógenos contribuyen al flujo y reciclaje del nitrógeno en los ecosistemas terrestres.

t.co/qpEXbwp2Ky

Global density and biomass of arbuscular mycorrhizal fungal networks 

Stewart et al., 2026

Most species of plants form underground associations with arbuscular mycorrhizal (AM) fungi, which provide plant roots with nutrients in exchange for carbon. AM fungi form networks of hyphae that act as tubes spreading carbon and connecting plants, but the global scale of these networks is unknown because of the difficulty of observing them underground. Compiled field and experimental data on hyphal density and used machine learning to predict how AM density varies across the globe. They then predicted hyphal biomass using high-resolution image analysis of hyphal network length from two globally distributed fungal species grown on transparent media in the lab. The authors predicted a large and spatially variable extent of AM fungi across the globe.

Arbuscular mycorrhizal fungi form symbioses with ~70% of plant species, building hyphal networks that exchange nutrients for host-derived carbon. These tubular networks move ~1 billion metric tons of carbon per year into Earth’s soils. However, we have no quantitative understanding of the hyphal infrastructure required to carry out this resource transfer. We assembled data from 322 studies representing more than 16,000 soil cores across nine biomes and developed machine-learning models to predict hyphal densities globally. With robotic imaging of more than 300,000 hyphae, we calibrated a biomass model from our spatial predictions. We estimate that global topsoils contain 1.10 × 1017 ± 0.13 × 1017 SD kilometers of living hyphae, weighing ~300 ± 60 SD megatons, ~4- to 6-fold the biomass of humans. Our uncertainty analyses identified undersampled ecosystems that require additional empirical attention.

https://www.science.org/doi/10.1126/science.adu4373

Maps:

https://a-hidden-infrastructure.spun.earth/story/mycorrhizal-infrastructure-map

https://www.spun.earth/underground-atlas/mycorrhizal-biodiversity

Agricultural intensification, microbial homogenization and loss of rare microbiota

Banerjee et al., 2026

To meet the needs of a growing human population, agricultural management practices have undergone substantial intensification, specialization and industrialization. This has contributed to biotic homogenization and a loss of diversity in microbial communities within agricultural systems. In this Perspective, we summarize recent studies that report microbial homogenization due to agricultural intensification. We propose a definition of microbial homogenization and explore how intensive agricultural practices can cause taxonomic, physiological, genetic and functional homogenization of microbial communities. Our analysis indicates that globally the diversity of rare taxa is lower in intensively managed agricultural lands compared with less-intensive lands and that agricultural intensification suppresses beneficial microorganisms and promotes pathogenic taxa. We identify microbial taxa that are sensitive to intensification and discuss how the disproportionate impact on rare microbiota can threaten agro-ecosystem functions and food security. Finally, we outline key challenges and suggest areas that require further research.

https://www.nature.com/articles/s41579-026-01315-w

From Math to Bio and Back: Reflections on a Two Way Street 

Steven Strogatz

Status of mycorrhiza research in 2026

Dallaire and Kameoka, 2026

Mycorrhizal symbiosis improves the nutrition of most land plants and plays key roles in nutrient cycling and ecosystem function. To understand and leverage the biology of mycorrhizal symbioses for sustainable agriculture and silviculture and the preservation of terrestrial ecosystems, molecular mechanisms enabling its establishment, function, and regulation are being investigated. Technological and conceptual advances are transforming the field and provide a detailed understanding of the mycorrhizal symbiosis on both the fungal and plant sides. In this viewpoint, we summarize recent advances that move the field toward a mechanistic understanding of mycorrhizal symbiosis, with a particular focus on studies presented at the 7th International Molecular Mycorrhiza Meeting (iMMM) held in Munich in September 2025.

https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.71119

Balancing mutualism: choice and sanctions in root–microbe symbioses

Madhavan et al., 2026

Plant roots form symbioses with beneficial microorganisms to enhance nutrient acquisition. Most terrestrial plants form arbuscular mycorrhizal symbiosis (AMS) with obligate biotrophic Glomeromycotina fungi, which supply hosts with mineral nutrients in exchange for carbon through specialized symbiotic hyphal structures (arbuscules) that develop within root cortex cells. Legumes form root nodule symbiosis (RNS) with nitrogen-fixing rhizobia, which are housed as differentiated bacteroids within specialized symbiotic organs (nodules) and provide plants with ammonia in return for carbon. RNS exhibits high partner specificity, occurring only between compatible hosts and microbes. Conversely, AMS is less specific, although symbiosis outcomes are context-dependent and influenced by host and fungal genotype, environmental conditions, and microbial competition. In both cases, plants favor high-performing microsymbionts by recognizing them during symbiosis initiation or by punishing low-performing symbionts through postcolonization sanctions. Microbes, in turn, employ strategies to manipulate plants for their own benefit. Here, we review the molecular mechanisms underlying partner preference in beneficial plant–microbe interactions and discuss how host partner selection strategies maintain mutualistic stability in AMS and RNS, alongside microbial strategies to evade host control. Understanding the dynamic interplay of functionally diverse plant–microbe symbioses provides a basis for improving mutualisms in both natural and agricultural systems.

https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.71107

Plant nutritional and structural diversity shape multitrophic arthropod communities and grassland productivity 

Lu et al., 2026

1. Arthropod communities, comprising diverse trophic groups such as herbivores, predators and parasitoids, are intricately linked to plant traits that provide food and habitat. While it is well-established that changes in plant functional diversity (e.g. trait identity and diversity) can significantly alter arthropod diversity across trophic levels, the cascading effects on ecosystem functions remain less understood. Particularly, the role of multitrophic arthropod diversity in mediating the relationship between plant functional diversity and grassland productivity presents a critical knowledge gap in ecosystem ecology.
2. We employed a long-term plant removal experiment in the Inner Mongolian grassland to systematically investigate how variations in the community-weighted mean and diversity of multiple plant traits influence the diversity (measured by taxon richness and abundance) of herbivores and their natural enemies. Furthermore, we explored how trophic interactions between herbivores and their natural enemies influence plant community productivity.
3. Our findings indicate that high diversity in plant nutritional traits (e.g. nitrogen, phosphorus and sodium contents) negatively impacts plant productivity through both direct and indirect pathways. The adverse effect was mediated by an increase in the richness of sucking and chewing herbivores, which exploited high resource complementarity yet collectively suppressed plant productivity. In contrast, higher community-weighted means of plant structural traits (e.g. vegetative height and leaf lateral spread) were associated with greater plant productivity. This positive effect appears to arise from enhanced top-down control, whereby predators—particularly spiders—reduced both the richness and abundance of herbivores.
4. Synthesis. Our study reveals that herbivores and their natural enemies respond distinctly to the variation in the composition and diversity of plant nutritional and structural traits. We show that cross-trophic interactions—specifically, diversity within herbivore and predator guilds—constitute a primary pathway through which plant functional diversity influences grassland productivity. By disentangling the links between plant trait spectra, arthropod community structure and ecosystem functioning, our findings provide key insights for biodiversity conservation and the design of ecosystem management strategies in grasslands.

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.70316