Presencia de fitoplasmas en papayo (Carica papaya) en México

tissue samples of papayo plants with mosaic and yellow crinkle symptoms collected from michoacan and veracruz were examined to detect phytoplasma with polymerase chain reaction (pcr), using primers derived from ribosomal rna 16s and 23s from phytoplasmas. the sequences of the amplified pcr products were homologous to polynucleotide sequences belonging to phytoplasmas. the restriction patterns obtained through digestion of the amplified dna evidenced the presence of two phytoplasmas in plants showing mosaic and yellow crinkle symptoms. one of them matched the aster yellow group 1 16s subgroup c. the patterns of the other phytoplasmas did not match any of the restriction patterns up to now reported. tissue from diseased plants reacted positively to the fluororochrome-4,6-dyamidino-2- phenylindol (dapi) which stains dna, therefore suggesting the presence of nucleic acids from biotic agents inside the phloem.