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