Expression Level of a Phenylalanine Ammonia-Lyase Gene in Poinsettia Is Negatively Correlated with Poinsettia Branch-Inducing Phytoplasma Titer.

Poinsettia is an important ornamental cultivated worldwide. Commercial poinsettias are almost universally infected with a pathogen known as the poinsettia branch-inducing phytoplasma (PoiBI), which can increase the level of branching in host plants and make the plants more desirable to consumers. Despite PoiBI's crucial role in poinsettia production, little is known about PoiBI-poinsettia interactions in regard to the pathogen's population dynamics.

Variability of Phytoplasma Infection Density in Poinsettia and Evaluation of its Association with the Level of Branching in Host Plants.

It has long been established that phytoplasma infection is the cause of the free-branching phenotype in poinsettia. However, relatively little is known about the ecology of the pathogen in planta. The present study evaluated the infection pattern of poinsettia branch-inducing phytoplasma (PoiBI) and its association with the poinsettia phenotype during cutting propagation.