Skip to main content

Research Repository

Advanced Search

The plant rhizosheath–root niche is an edaphic “mini-oasis” in hyperarid deserts with enhanced microbial competition


Ramona Marasco

Marco Fusi

Jean-Baptiste Ramond

Marc W. Van Goethem

Kholoud Seferji


Don A. Cowan

Daniele Daffonchio


Plants have evolved unique morphological and developmental adaptations to cope with the abiotic stresses imposed by (hyper)arid environments. Such adaptations include the formation of rhizosheath–root system in which mutualistic plant–soil microbiome associations are established: the plant provides a nutrient-rich and shielded environment to microorganisms, which in return improve plant-fitness through plant growth promoting services. We hypothesized that the rhizosheath–root systems represent refuge niches and resource islands for the desert edaphic microbial communities. As a corollary, we posited that microorganisms compete intensively to colonize such “oasis” and only those beneficial microorganisms improving host fitness are preferentially selected by plant. Our results show that the belowground rhizosheath–root micro-environment is largely more hospitable than the surrounding gravel plain soil with higher nutrient and humidity contents, and cooler temperatures. By combining metabarcoding and shotgun metagenomics, we demonstrated that edaphic microbial biomass and community stability increased from the non-vegetated soils to the rhizosheath–root system. Concomitantly, non-vegetated soil communities favored autotrophy lifestyle while those associated with the plant niches were mainly heterotrophs and enriched in microbial plant growth promoting capacities. An intense inter-taxon microbial competition is involved in the colonization and homeostasis of the rhizosheath zone, as documented by significant enrichment of antibiotic resistance genes and CRISPR-Cas motifs. Altogether, our results demonstrate that rhizosheath–root systems are “edaphic mini-oases” and microbial diversity hotspots in hyperarid deserts. However, to colonize such refuge niches, the desert soil microorganisms compete intensively and are therefore prepared to outcompete potential rivals.


Marasco, R., Fusi, M., Ramond, J., Van Goethem, M. W., Seferji, K., Maggs-Kölling, G., …Daffonchio, D. (2022). The plant rhizosheath–root niche is an edaphic “mini-oasis” in hyperarid deserts with enhanced microbial competition. ISME Communications, 2(1), Article 47.

Journal Article Type Article
Acceptance Date May 9, 2022
Online Publication Date Jun 3, 2022
Publication Date 2022
Deposit Date Jun 6, 2022
Journal ISME Communications
Print ISSN 2730-6151
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 2
Issue 1
Article Number 47
Keywords Environmental microbiology, Microbial ecology
Public URL