Under natural environment, plants growing in low-nutrient soils are
often associated with microbes that can promote nutrient acquisition.
However, the plant signal cascades linking the response to
nutrient deficiency with the establishment of beneficial interactions
remains elusive. Here we use Arabidopsis thaliana growing in natural
soils that vary in nutrient level as a model system to study the
molecular mechanism of microbe recruitment. As a new initiative,
we screened soils for beneficial microbes that contribute to plant
nutrition across a wide range of Danish habitats.
Our studies show that soil samples collected from four sites contain
microbes that ensure the maintenance of magnesium, phosphorus,
and sulfur levels in mature rosette leaves of Arabidopsis Col-0 (unpubl.
data). By comparing plant-associated microbiota with microbiota
from bulk soil, we identified many root-enriched operational
taxonomic units (OTUs). To target the root microbial consortia
responsible for plant nutrition, we developed a plant transplantation-
based method and showed that the endophytic microbes are
sufficient for maintaining magnesium level in plants growing in one
site. Identification of beneficial microbes will focus on endophytic
microbial culture.
In summary, combining the phenotype-based screening with the
transplantation experiments simplify the workflow for culture-dependent
identification of beneficial microbes required for plant nutrition
and paves the way for investigation of the mechanism of the
establishment of the beneficial community.