Occurrence of a 16SrIV Group Phytoplasma not Previously Associated with Palm Species in Yucatan, Mexico

The occurrence of 16SrIV group phytoplasmas in palm species Sabal mexicana and Pseudophoenix sargentii is reported here for the first time. Palm trees showed leaf decay and leaf yellowing syndromes, respectively. An amplification product (1.4 kb) was obtained in symptomatic S. mexicana (18 of 21) and symptomatic P. sargentii (1 of 1) palm trees sampled in different locations in Yucatan State, Mexico; five of the positive S. mexicana and the positive P. sargentii trees died. The identity of the phytoplasmas from these species was determined by restriction fragment length polymorphism profiling with restriction enzymes AluI and HinfI, showing there could be two phytoplasma strains of the 16SrIV group. In one S. mexicana palm, the profile was the same as observed with these enzymes for phytoplasmas of 16SrIV-A subgroup, previously associated with Cocos nucifera palm trees and, in the rest of the trees, including the P. sargentii palm, the profile was for phytoplasmas of the 16SrIV-D subgroup. These identities were supported by analyses of the amplicons obtained by nested polymerase chain reaction by nucleotide-nucleotide BLAST analysis. Geographical distribution of the association S. mexicana/16SrIV group phytoplasmas was found widely dispersed in Yucatan State. A potential role of S. mexicana palm trees as a permanent source of phytoplasma inoculum is suggested. In addition to P. sargentii, other palm species (Thrinax radiata and C. nucifera) coexisting with S. mexicana trees were also sampled and analyzed.

Estudio preliminar de la diversidad genética en procedencias de Sabal mexicana de Nicaragua aplicando marcadores moleculares

PARA EVALUAR DE FORMA PRELIMINAR LA VARIABILIDAD GENÉTICA de 12 procedencias de Sabal mexicana Mart. en el Occidente de Nicaragua, se aplicó la técnica Random Amplified Polymorphic DNA (RAPD). De las 42 bandas generadas por seis cebadores en una muestra de 44 individuos, 92.8% resultaron polimórficas. El mayor polimorfismo lo presentaron las procedencias en las cuales se analizó un mayor número de muestras (5), destacándose El Limonal (82.78%) y Santa Rosa (78.82%). El agrupamiento de las muestras en un dendrograma refleja alta diversidad genética entre ellas (25% de similitud). La mayoría de las muestras se ubican independientemente de la procedencia a la que pertenecen y de su localización geográfica, lo que puede ser debido principalmente al pequeño número de muestras (máximo 5) por procedencia, aunque también puede ser el resultado del pequeño número de cebadores (6) y a que, probablemente, la mayor diferencia genética se encuentre dentro y no entre las procedencias