WHEATSYM

Cereals require high quantities of fertilizers which represent an unsustainable economic and environmental cost. The symbiosis with arbuscular mycorrhizal (AM) fungi which occurs in most plants including cereals, allows a better access to soil nutrients. Another symbiosis with nitrogen-fixing bacteria called rhizobia, which is restricted to legumes, allows plants to obtain all their nitrogen requirements from atmospheric nitrogen fixation. Rhizobia do not form a nitrogen-fixing symbiosis with cereals but can be found as endophytes in cereal roots. AM fungi and rhizobia produce signal molecules with similar structure called chitooligosaccharides (COs) and lipo-chitooligosaccharides (LCOs). These signals are perceived by host plants, are essential for establishment of the nitrogen-fixing symbiosis in legumes and have been shown to stimulate establishment of the AM symbiosis with different plant species. In addition, crop treatments with these molecules improve yields. The project aims to both understand the perception mechanisms for these signals and determine whether manipulation of these mechanisms in wheat leads to improved responses to COs, LCOs and mycorrhizal fungi. Ultimately, the project aims to determine whether manipulation of CO/LCO perception leads to enhanced wheat colonization by rhizobia, a first step towards developing a nitrogen-fixing symbiosis in cereals. CO and LCO receptors will be identified using a combination of reverse genetic and biochemical approaches. Brachypodium distachyon, a model plant close to wheat, will be used to facilitate and accelerate identification of the receptors among candidates from the Lysin Motif Receptor-Like Kinase and Receptor-Like Protein (LysM-RLK/RLP) family. Orthologs of B. distachyon CO and LCO receptors will then be identified and manipulated in wheat. The project consortium unites two public sector- and one private company- partners with complementary tools and expertise to achieve the goals of this project.