The influence of wheat microbiomes on drought stress resilience

Wheat is the most grown crop plant by area worldwide and a widely valued part of western
human diet. However, drought periods, that are projected to increase due to climate change,
pose a major agricultural risk to crop yields. One potential strategy to increase drought stress
resilience of wheat is the application of plant-growth promoting bacteria. In this study, we aimed
to identify drought stress suppressing microbiomes through plant phenotype monitoring.
Furthermore, bacteria were isolated from the rhizosphere of drought stressed wheat to
decipher the plant-microbe interactions during drought
We cultivated wheat plants in 20 distinct agricultural soils collected across Lower Austria in
greenhouse trails. To simulate drought stress, a water withholding regime was applied. The
five best and worst performing soils in elevating drought stress resilience were selected based
on dry weight, stomatal conductance, as well as water and chlorophyll content. To control for
potential abiotic factors, living microbial cells were extracted using a 0.2% pyrophosphate
solution from each of the selected soils and used as an inoculant for a subsequent experiment.
Inoculated wheat plants were grown in steamed artificial soil under drought stress and
controlled conditions to assess the effect of soil microbiomes and stress on the plant phenotype
and wheat-associated microbiomes. Drought stress had an impact on plant growth, whereas
different soil microbiomes had only minor effects. Treatments with three different soils were
selected based on their effect on plant traits. Root and rhizosphere microbiomes of stressed
and unstressed plants were subjected to 16S rRNA gene amplicon sequencing as well as
isolation campaigns. As Flavobacterium strains were prominently isolated, a comparative
genomics analysis has been initiated. We will present results on how drought stress affects
wheat growth when grown in identical soils but containing distinct microbiota.