EGU22-8562, updated on 28 Mar 2022
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Effect of root hairs and benzoxazinoids on maize microbiome and its enzymatic activity in the rhizosphere

Nataliya Bilyera1,2, Jan Waelchli3, Lingling Shi4,5,6, Veronica Caggia7, Xuechen Zhang5, Klaus Shlaeppi3,7, Michaela A. Dippold5,6, Bahar S. Razavi1, and Sandra Spielvogel2
Nataliya Bilyera et al.
  • 1Department of Soil and Plant Microbiome, Christian-Albrechts-University of Kiel, Kiel, Germany (
  • 2Department of Soil Science, Christian-Albrechts-University of Kiel, Kiel, Germany
  • 3Plant Microbe Interactions, Department of Environmental Sciences, University of Basel, Basel, Switzerland
  • 4Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
  • 5Department of Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany
  • 6Geo-Biosphere Interactions, University of Tuebingen, Tuebingen, Germany
  • 7Institute of Plant Sciences, University of Bern, Bern, Switzerland

Root morphology and the composition of root exudates shape the spatial organization and various processes in the rhizosphere. For instance, root hairs are essential for plant nutrition, while secondary plant metabolites (i.e. benzoxazinoids) ensure plant defence from herbivore and fungal infection. Nevertheless, it is still unknown to which extent root hairs and benzoxazinoids may change the microbiome and enzymatic activities, as well as formation of rhizosphere hot- and coldspots.

To study the effect of root hairs and benzoxasinoids on the rhizosphere microbiome structure and its enzymatic activities we compared mutants with defective root hairs rth3 or with reduced benzoxazinoids bx1 with the corresponding wild-type (WT) maize.

Root hairs increased acid phosphatase activity by 80 % promoting mineralization of organic phosphorus sources to available forms in the hotspots. In the coldspots, broken root hairs in WT facilitated the intensive microbial hotspots with up to two times higher β-glucosidase and chitinase activities, compared to rth3.

The presence of benzoxazinoids in root exudates strongly supported plant defence against pathogenic fungi (i.e., genus Fusarium and Gibberella) while the total microbial biomass remained unaffected. In response to the presence of pathogenic fungi, bx1 exuded 70 % more chitinase for defence purpose to partly compensate for benzoxazinoids deficiency, which was however, less efficient against pathogens than the presence of benzoxazinoids.

Overall, we conclude that: i) root hairs facilitate better plant nutrition at the shortage of available nutrients (i.e., coldspots), while; ii) the presence of benzoxazinoids in exudates protect plant from pathogenic microorganisms. This two root traits are promising for plant breeding of genotypes suitable for sustainable agriculture and organic farming.

How to cite: Bilyera, N., Waelchli, J., Shi, L., Caggia, V., Zhang, X., Shlaeppi, K., Dippold, M. A., Razavi, B. S., and Spielvogel, S.: Effect of root hairs and benzoxazinoids on maize microbiome and its enzymatic activity in the rhizosphere, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8562,, 2022.