Acclimation
Once two populations, (one axenic, the other with its microbiome, both founded from the same common ancestor,) were obtained for each genotype, all cultures were acclimated for an additional two weeks in a controlled common garden setting to remove any maternal effects and ensure an equal physiological starting point for all plants. Each population, consisting of ~150 individuals, was grown in a stoppered 500mL Erlenmeyer flask filled with 350mL of diluted Hoagland’s E-media ([N]=2750 µg L-1 and [P]= 423.5 µg L-1) placed in controlled growth chambers of the McGill phytotron (165 µmols m-2 s-1light, 200C, 70% relative humidity, with a 14/10 light-dark cycle).