Cereals endophytes : biostimulation and biocontrol

SYMUNITY team / Pascal Ratet

Cereals (wheat, barley, etc.) are important plant species from an agronomic point of view. Like all plant crops, they are subjected to abiotic and biotic stresses. To adapt to these different stresses, cereals set up defense and/or adaptation mechanisms. They can also associate with beneficial microorganisms allowing them to grow better (biostimulation) and/or defend themselves against pathogens (biocontrol).

Our team uses two cereal species: wheat (Triticum aestivum) and Brachypodium distachyon, and studies the impact of beneficial soil microorganisms on their growth and protection against diseases.

Interactions between cereals and diazotrophic bacteria

Field crops such as wheat, barley, corn require the addition of chemical fertilizers for their growth. We would like to know if these crops are able to interact with microorganisms fixing atmospheric nitrogen. Nitrogen (N2) fixing endophytes are for example present in sugarcane. We have isolated root endophytes capable of fixing nitrogen in vitro from organically grown wheat (field plants cultivated without synthetic fertilizers). Several bacteria were isolated and the genome of one of them was sequenced (unpublished data). Preliminary experiments indicate a close association of one of these strains with wheat roots. Further experiments will show whether this bacterium can behave as an endophyte and/or promote the growth of wheat or Brachypodium.

Trichoderma sp.: biocontrol agent, biostimulation agent or both?

The second part of the study is to investigate the impact of the interaction between the fungus Trichoderma sp. and wheat. To do this we study the effect of the interaction on: (1) the stimulation of plant growth and (2) the protection against wheat rust. This project in the framework of a thesis (cotutelle) with Lebanon will allow to better understand the mechanisms controlling this beneficial interaction