The rhizosphere microbiome, a new way to control Striga hermonthica?

Striga hermonthica is a root parasitic plant, causing
major damage to the production of crops and controlling Striga is hard, since
the life cycle of Striga is closely linked to its host plant. Methods to
control Striga have mainly focused on developing Striga-resistant or Striga-tolerant
species. The rhizosphere microbiome has been the focus of a new method as the
microbiome can support the plant through controlling diseases directly or
influence the plants defense mechanism.

The goal of this research
was to examine how microbes could help crops resist Striga. Changes in
expression of the Pathogenesis-related 3 gene, the Hypersensitive response 1
gene and a cytochrome p450 gene were studied in 2 genotypes of Sorghum. This
was done in a more resistant genotype, Sb13 (Debir), and a more susceptible
genotype, SQR (Shanqui red), in sterile and nonsterile soil. Here, it was
demonstrated that the two genotypes exhibit a different expression pattern and
seemingly have different tactics in using the microbiome to resist Striga.

Moreover, a germination
assay was conducted to unravel the interactions that takes place in the
rhizosphere. Sorghum plants were grown for 3, 6 or 11 days after transferring
the seedlings. Root exudates were collected at these timepoints and Striga seeds
were treated with the collected root exudates. Here, it was observed that
the microbiome has an influence on the development of the germinated Striga
seeds. More haustoria structures were formed in the absence of a
microbiome (in sterile soil). It was also observed that Striga seeds
germinated more when treated with root exudates from time point 3, although not
significantly.

This study gives insight in
the potential of the rhizosphere microbiome as a new method to control Striga. Future
research is still necessary to fully understand the effect of the microbiome
and the mechanisms behind it.