Ocorrência de fitoplasma associado á síndrome do amarelecimento foliar da cana-de-açúcar em três regiões do Estado de São Paulo

Abstract

Sugarcane yellow leaf syndrome caused serious damage to crops in the São Paulo State, Brazil, in the 1990's. The syndrome was also reported in other countries and investigations into the etiology revealed an association between the disease and virus and/or phytoplasma. The disease is potentially important and occurs endemically in that State, and for this reason the present study was conducted in order to demonstrate the occurrence of phytoplasma in three traditional sugarcane-producing areas, in São Paulo State, through molecular detection from naturally infected plants. Symptomatic plants belonging to varieties SP71-6163, SP71-6180 and SP89-1115 were sampled from Piracicaba, Jaú and Ribeirão Preto, and total DNA was extracted from foliar tissues. Nested PCR was conducted with primer pairs P1/Tint-16F2n/R2, and the amplified products were analyzed by electrophoresis on agarose gels. Amplified DNA fragments of 1.2 kb evidenced the presence of phytoplasma in 36% of symptomatic plants and revealed its occurrence in all sampled regions. The results demonstrated that phytoplasma is associated with the disease and that it is important to keep a safe inspection of nurseries and monitoring plants in the field, as well as to select sugarcane genotypes with a good level of resistance in breeding programs. Copyright by the Brazilian Phytopathological Society.