ETIOLOGY OF CLADODE THICKENING OF PRICKLY PEAR CACTUS (Opuntia ficus-indica (L.) Mill.) IN MEXICO

Abstract

Mexico ranks first in prickly pear production in the world and one of the main producing areas of the country is located at the eastern of the state of Mexico. Cladode thickening is one of the most important diseases in this region and reduces prickly pear production. In Mexico, research to determine the cause of this disease has shown the presence of an associated phytoplasma; however, its ultimate etiology remains unknown. The objective of this research was to transmit by grafting, in 20 healthy in vitro cultured prickly pear cactus plants, phytoplasma associated to cladode thickening. The hypothesis was that these plants would show symptoms of thickening due to the associated phytoplasma. All grafted plants showed yellowing, reduced growth and deformation of young cladodes. The presence of the phytoplasma in the grafted plants was corroborated by nested PCR with universal primers that amplify a fragment of approximately 1200 bp. Evidence showed that the etiology of cladode thickening in prickly pear is due to Candidatus phytoplasma.