Methods, plants and compositions for overcoming nutrient suppression of mycorrhizal symbiosis

A method of cultivating a genetically altered plant with increased mycorrhization and/or promoted symbiotic responses under conditions comprising a phosphate level around the plant roots that suppresses mycorrhization and/or symbiotic responses, comprising:

• a) providing the genetically altered plant,
• wherein the plant or a part thereof comprises one or more genetic alterations that result in increased activity of a NODULATION SIGNALING PATHWAY 1 (NSP1) protein, a NODULATION SIGNALING PATHWAY 2 (NSP2) protein, or both a NSP1 protein and a NSP2 protein as compared to an activity of a NSP1 protein or a NSP2 protein in a wild type (WT) plant grown under the same conditions, and
• wherein the one or more genetic alterations reduce the phosphate level suppression of mycorrhization and/or symbiotic responses;
• and
• b) cultivating the genetically altered plant under the phosphate level around the plant roots,
• wherein the genetically altered plant has increased mycorrhization and/or promoted symbiotic responses as compared to the WT plant grown under the same conditions.