P16 - Rhizosphere Microbiome

Spatiotemporal organization of the rhizosphere microbiome shaped by external drivers

CLSM of corn plant roots inoculated with Bacillus amyloliquefaciens FZB42 gfp or Pseudomonas sp. RU47 rfp (Eltlbany et al. unpublished)

The rhizosphere microbiome plays an important role for soil ecosystem functions, plant growth and health. Self-organization of the rhizosphere arises from feedback loops between root, microbiome and soil. In phase I, we investigated the microbiome associated with the rhizosphere of two maize genotypes wild type (WT) and root hair defective mutant (rth3) in two distinct substrates loam (L) and sand (S) in central soil column experiments in a growth chamber (SCE) and a soil plot experiment in the field (SPE). Sequence analysis of 16S rRNA gene and ITS amplicons from total community (TC)-DNAs revealed that the substrate was the strongest driver shaping the maize rhizosphere microbiome followed by soil depth and maize genotype (SCE and SPE). Unexpectedly, the maize root hairs had only minor effects on the rhizosphere microbiome, in SCE and SPE. In phase II we will continue to unravel spatial organization of the rhizosphere microbiome of maize depending on the substrate and the presence of external drivers (inoculation of a consortium of beneficial microorganisms [BMs], drought conditions). We will participate in the central experiments performed both at lab (SCE_Drought) and field (SPE_BBCH19) scale, and will carry out central satellite experiments using pots and rhizoboxes (RB_Drought_BM). We will reveal how important maize root hairs and the inoculation of a consortium of BMs is for maize growth performance and the rhizosphere/rhizoplane microbiome under drought conditions. The role of root hairs and spatial pattern (root tip, root base and different soil depths) of the rhizosphere microbiome of maize affected by drought and/or inoculated BMs will be investigated in a polyphasic and interdisciplinary approach. For the SPE_BBCH19, we will participate in the complex sampling to uncover the effects of continuation of maize monoculture on changes in the rhizosphere microbiome related to substrate and maize genotype, using the MisSeq amplicon sequencing and qPCR. Applying the concept of self-organization to the rhizosphere and unique interdisciplinary approaches used to investigate the central experiments will enable us to gain a better understanding of the spatiotemporal rhizosphere microbiome patterns and how they are influenced by external drivers.

Link to English scientific abstract

Link to German scientific abstract