Pi inhibits the formation of Vd micosclerotia in roots, irrespective of whether the roots were first exposed to Pi ( 1P2V ) or first to Vd ( 1V2P ). The analysis was performed 21 days after infection. Left: microscopy of root sections with microslerotia (black spots). Right: Quantification of the number of microsclerotia. The data are based on 3 independent experiments with 12 seedlings each. Bars represent SDs. Asterisks indicate significant differences to Vd, as determined by Student's t-test (* P ≤ 0.05; ** P ≤ 0.01; *** P ≤ 0.001).