Quantification over time of chrysanthemum yellows phytoplasma (16Sr-I) in leaves and roots of the host plant Chrysanthemum carinatum (Schousboe) following inoculation with its insect vector

Abstract

The rate of increase of chrysanthemum yellows phytoplasma (CYP, 16Sr-I) in leaves and roots of the host plant Chrysanthemum carinatum following localised and free insect inoculation is described. The fate of CYP in each test plant has been monitored over time using a relative quantification method based on real time PCR. Significant differences in CYP titre have been found both in apical leaves and roots sampled at different times post inoculation. CYP was much more concentrated in young apical leaves and roots compared to old basal leaves. Few thousands and few hundred thousands CYP genome units per nanogram of plant DNA were the maximum amounts found in leaves and roots, respectively. Active movement of CYP towards young developing leaves and roots has been demonstrated.