Evaluation of molecular markers for the characterization of Xylella fastiosa strains associated to CVC and coffee leaf scorch (requeima do cafeeiro)

Abstract

The search for taxonomic and phylogenetic markers for Xylella fastidiosa is critical for the development of epidemiological studies and characterization of strains which affect several economically important crops in Brazil, including orange trees, coffee and plum. The application of conventional and some molecular characterization methods usually require the isolation strains in pure culture and growth, a tedious and very laborious process in the case of slow-growing Xylella fastidiosa. The current study aims at the evaluation of distinct phylogenetic markers, including 16S-23S rDNA spacer regions, dnaK, groEL and recA genes, for the molecular characterization of Xylella fastidiosa strains associated with eve and coffee leaf scorch, and to determine the level of taxonomic resolution that can be attained with analyses of polymorphism of these markers using rapid and sensitive analytical techniques, such as DGGE. Sequence analysis of polymorphic gene fragments will be applied to the development of specific PCR primers for these markers in Xylella fastidiosa, which would enable the detection and direct typing of strains using plant-extracted DNA. (AU)