Abstract

In Mexico in the region of Nopaltepec in Mexico State, the edible Cactus crop, Opuntia ficus-indica is mainly cultivated for prickly pear fruit production. This crop has problems with common pests (insects, mollusks and weeds) which may serve as reservoirs and together with the named Cactus with phytoplasma-like symptoms which through the time inhibit the fruit production, and for this reason, the farmers called these Opuntia plants as Planta Macho (male plant). For molecular identification of the probably involved phytoplasma during 2005 and 2006, 38 samples of Opuntia plant tissues, fruit and some pests were collected for DNA extraction. By direct and nested PCR, 16S rRNA gene was amplified and sequenced. PCR products were analyzed by RFLP with restriction  enzymes and in the sequences restriction sites were mapped. Phylogenetic analysis showed that the same phytoplasma was associated with Opuntia crop and its pests (the weeds Argemone mexicana, a grass and Lupinus sp.; a chinch bugs, Chelinidea sp. and the brown garden snail, Helix aspersa). Thus the edible Cactus crop and pests represented novel hosts of Cactus male plant Phytoplasma, and was classified as 16SrI Aster yellows group, of the species Candidatus phytoplasma asteris. This is the first report of this phytoplasma in Mexico and elsewhere.   

Key words: Argemone, brown garden snail, chinch bugs, edible Cactus, grasses,Lupinus, male plant phytoplasma, Mexico.