Authors
Giuliano E, Jagdeep Singh Sidhu, Ivan Lopez-Valdivia, Rafaela Feola Conz, Cody DePew, JP Lynch, Johan Six, Martin Hartmann, Tania Galindo-Castañeda
Source
Plant and Soil
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Abstract
Background and aims
Drought threatens food security globally. Adaptive root phenotypes and microbiomes can improve maize (Zea mays L.) water uptake and tolerance to drought. However, synergisms between root phenotypes and microbiomes remain underexplored. We aimed to investigate the association between varying root anatomies and architectures and the rhizosphere microbiome under field-scale drought.
We grew 22 maize inbred lines in the field under optimal water availability and drought imposed by excluding rain with rainout shelters. We quantified grain yield and measured root architectural and anatomical phenotypes on root crown and cross-section images obtained by laser ablation tomography, respectively. We characterized rhizosphere prokaryotic and fungal communities with DNA metabarcoding of ribosomal markers.
Results
Rhizosphere microbial diversity predominantly associated with root anatomy rather than root architecture. Cortical parenchyma wall width explained 13.1% of the variance of the prokaryotic β-diversity and correlated with grain yield under control conditions. Under the same conditions, number of cortical cell files and metaxylem vessels explained 1.4-2.1% of the variance of prokaryotic and fungal β-diversities. No effect of the root phenotypes was observed under drought. We found 222 significant correlations between taxa abundances and root anatomical phenotypes, especially cortex-related phenotypes such as number of cell files and living cortex area. Overall, a greater number of correlations was found under control conditions.
Conclusion
We identified root phenotypes explaining a small but significant percentage of the variance of the microbial β-diversity, mostly under optimal water availability. We showed that especially root anatomy is associated with rhizosphere microbial diversity in field-grown maize.
