Entre 1990 et 2010, la capacité de stockage des forêts a chuté d’environ 30 %. Tour d’horizon, de l’Amazonie à l’Afrique centrale, en passant par des forêts tempérées et boréales.

Organisms are commonly grouped into ecological guilds that reflect their shared resource use and similar ecological roles. The guild concept has been …

Litter decomposition is coupled to carbon (C) sequestration through C release to the atmosphere, C transformation and nutrient release to the soil. We…

Quand vous partez à la cueillette de champignons, ne vous fiez pas aux applications de reconnaissance sur smartphone pour les identifier et adoptez les bons gestes pour éviter les intoxications.

Cell division and specification are crucial for plant development and coping with diverse environmental cues. Most land plants rely on symbiosis with arbuscular mycorrhizal (AM) fungi to cope with soil nutrient limitations by forming arbuscules in root inner cortex cells. What determines the AM susceptibility of these inner cortex cells is currently unknown. Here we show that DELLA transcriptional regulators control the number of inner cortex cells with an AM-susceptible identity at the root stem cell niche of Medicago truncatula in a dose-dependent manner. Genetic analyses suggest that this activity converges with the well-known mobile SHORT-ROOT transcription factor regulating ground tissue development. Furthermore, we show that MtDELLA1 protein moves from the stele/endodermis to the cortex in the mature part of the root to facilitate arbuscule formation. We propose that the formation of a root inner cortex cell identity controlled by mobile DELLA and SHORT-ROOT is a fundamental basis for AM symbiosis.

Plants form mycorrhizal symbioses to enhance nutrient acquisition, yet the biophysical principles governing carbon and nutrient exchange remain unclear. Here, we develop a theory of bi-directional carbon–nutrient transfer that integrates root anatomy, energetic costs, and mycorrhizal positioning. We show that nutrient uptake per unit carbon or energy investment declines with increasing root diameter due to higher carbon demands across thicker cortical tissues. Mycorrhizal fungi mitigate this constraint by enabling more carbon-efficient nutrient uptake, particularly when arbuscules are positioned in inner cortical layers. This spatial optimization minimizes the carbon cost of transporting nutrients to the stele. Our framework reconciles anatomical variation, symbiotic structure, and functional efficiency across root types and mycorrhizal strategies and offers a new lens for understanding the coevolution between roots and mycorrhizal fungi.

Christophe Galfard reçoit la poète Laura Vasquez et les deux scientifiques Francis Martin et Marie-Béatrice Bogeat.

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La vitesse de croissance des arbres va de pair avec leur capacité à séquestrer le CO₂. Mais les espèces les plus rapides sont aussi souvent plus fragiles face aux stress environnementaux.

A super-pangenome analysis incorporating 123 newly sequenced bryophyte genomes reveals that bryophytes exhibit a larger number of unique and lineage-specific gene families than vascular plants.