Rhizosheath microbial community assembly of sympatric desert speargrasses is independent of the plant host

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dc.contributor.author Marasco, Ramona
dc.contributor.author Mosqueira, María J.
dc.contributor.author Fusi, Marco
dc.contributor.author Ramond, Jean-Baptiste
dc.contributor.author Merlino, Giuseppe
dc.contributor.author Maggs-Kölling, Gillian
dc.contributor.author Booth, Jenny M.
dc.contributor.author Cowan, Don A.
dc.contributor.author Daffonchio, Daniele
dc.date.accessioned 2019-10-10T06:19:02Z
dc.date.available 2019-10-10T06:19:02Z
dc.date.issued 2018-12
dc.description.abstract Background The rhizosheath-root system is an adaptive trait of sandy-desert speargrasses in response to unfavourable moisture and nutritional conditions. Under the deserts’ polyextreme conditions, plants interact with edaphic microorganisms that positively affect their fitness and resistance. However, the trophic simplicity and environmental harshness of desert ecosystems have previously been shown to strongly influence soil microbial community assembly. We hypothesize that sand-driven ecological filtering constrains the microbial recruitment processes in the speargrass rhizosheath-root niche, prevailing over the plant-induced selection. Methods Bacterial and fungal communities from the rhizosheath-root compartments (endosphere root tissues, rhizosheath and rhizosphere) of three Namib Desert speargrass species (Stipagrostis sabulicola, S. seelyae and Cladoraphis spinosa) along with bulk sand have been studied to test our hypothesis. To minimize the variability determined by edaphic and climatic factors, plants living in a single dune were studied. We assessed the role of plant species vs the sandy substrate on the recruitment and selection, phylogenetic diversity and co-occurrence microbial networks of the rhizosheath-root system microbial communities. Results Microorganisms associated with the speargrass rhizosheath-root system were recruited from the surrounding bulk sand population and were significantly enriched in the rhizosheath compartments (105 and 104 of bacterial 16S rRNA and fungal ITS copies per gram of sand to up to 108 and 107 copies per gram, respectively). Furthermore, each rhizosheath-root system compartment hosted a specific microbial community demonstrating strong niche-partitioning. The rhizosheath-root systems of the three speargrass species studied were dominated by desert-adapted Actinobacteria and Alphaproteobacteria (e.g. Lechevalieria, Streptomyces and Microvirga) as well as saprophytic Ascomycota fungi (e.g. Curvularia, Aspergillus and Thielavia). Our results clearly showed a random phylogenetic turnover of rhizosheath-root system associated microbial communities, independent of the plant species, where stochastic factors drive neutral assembly. Co-occurrence network analyses also indicated that the bacterial and fungal community members of the rhizosheath-root systems established a higher number of interactions than those in the barren bulk sand, suggesting that the former are more stable and functional than the latter. Conclusion Our study demonstrates that the rhizosheath-root system microbial communities of desert dune speargrasses are stochastically assembled and host-independent. This finding supports the concept that the selection determined by the desert sand prevails over that imposed by the genotype of the different plant species. en_ZA
dc.description.department Biochemistry en_ZA
dc.description.department Genetics en_ZA
dc.description.department Microbiology and Plant Pathology en_ZA
dc.description.sponsorship Financially supported (baseline fund to DD) by King Abdullah University of Science and Technology (KAUST). JBR and DAC were supported by the South African National Research Foundation (grant number 95565). JBR was also supported by the Research Development Program (RDP) of the University of Pretoria. en_ZA
dc.description.uri https://microbiomejournal.biomedcentral.com en_ZA
dc.identifier.citation Marasco, R., Mosqueira, M., Fusi, M., et al., 2018,'Rhizosheath microbial community assembly of sympatric desert speargrasses is independent of the plant host', Microbiome, vol. 6, art. 215, pp. 1-18. en_ZA
dc.identifier.issn 2049-2618 (online)
dc.identifier.other 10.1186/s40168-018-0597-y
dc.identifier.uri http://hdl.handle.net/2263/71773
dc.language.iso en en_ZA
dc.publisher BMC en_ZA
dc.rights © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/). en_ZA
dc.subject Rhizosheath-root system en_ZA
dc.subject Plant-microbe interactions en_ZA
dc.subject Speargrasses en_ZA
dc.subject Stochastic assembly en_ZA
dc.subject Holobiont en_ZA
dc.subject Desert environment en_ZA
dc.subject Microbiome en_ZA
dc.title Rhizosheath microbial community assembly of sympatric desert speargrasses is independent of the plant host en_ZA
dc.type Article en_ZA


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