Abstract: The invention relates to a method of determining an association of a first plant with an arbuscular mycorrhizal fungus (AMF), said method comprising comparing the amount of a blumenol in an aerial part of said first plant to the amount of said blumenol in an aerial part of a second plant, wherein said second plant belongs to the same species as said first plant, and wherein an increased amount is indicative of increased association in said first plant as compared to said second plant, and a decreased amount is indicative of decreased association.

Abstract: The present invention relates to a compound of general formula (I) or an enantiomer, diastereomer, stereoisomer, which mediates resistance against leaf- and planthopper pests. The present invention further relates to a method of producing the compound, an enzymatic production method the compound using at least a BBL2 polypeptide, as well as a PPO, AT1, ODC, HPL, PAL, C4H, 4CL, HCT and/or C3H activity. Further envisaged are genetically modified organisms producing the compound, expression cassettes for heterologous expression of the activities, the use of corresponding polypeptides and polynucleotides for the production of the compound, a composition including the compound, as well as uses of the compound for plant protection.

Abstract: The invention relates to a method of determining an association of a first plant with an arbuscular mycorrhizal fungus (AMF), said method comprising comparing the amount of a blumenol in an aerial part of said first plant to the amount of said blumenol in an aerial part of a second plant, wherein said second plant belongs to the same species as said first plant, and wherein an increased amount is indicative of increased association in said first plant as compared to said second plant, and a decreased amount is indicative of decreased association.