Genetic Diversity and Geographical Distribution of Phytoplasmas Associated with Potato Purple Top Disease in Mexico.

Potato purple top (PPT) disease has caused severe economic losses in some potato (Solanum tuberosum) growing areas of Mexico. Two distinct phytoplasma strains belonging to the aster yellows and peanut witches'-broom groups (16SrI and 16SrII groups) have been associated with PPT disease in several regions of Mexico. However, there has been no previous large-scale survey in the main potato growing areas in Mexico to analyze the diversity and geographical distribution of phytoplasmas.