Phylogenetical studies of Candidatus Liberibacter asiaticus in Misiones Argentina

BADARACCO ALEJANDRA; REDES FRANCO JONATHAN; AGOSTINI, JUAN PEDRO

Foz de Iguazu

Congreso; Internacional Citrus Congress; 2016

Citrus huanglongbing (HLB) is one of the most devastating diseases of citrus and is characterized by blotchy mottling with green islands on leaves, as well as stunting, fruit decline, and small, lopsided fruits with poor color. The disease is associated with phloem-limited bacteria named ?Candidatus Liberibacter spp.? Currently, three species of ?Ca. Liberibacter? are recognized: ?Ca. L. asiaticus (CLAS)?, ?Ca. L. africanus?, and ?Ca. L. americanus?. In Misiones Argentina, trees positive for CLAS were detected. The aim of this study was to analyze the phylogeny of CLAS. Ten positive samples were used. Leaf samples were collected between 2014 and 2016 from different locations in Misiones. The DNA extraction were performed using the CTAB method. DNA from all leaf samples were amplified by PCR using specific primers for the 16S rRNA gene region. The PCR products obtained were purified and sequenced for phylogenetic analysis. Sequences obtained in this study and those available in the GenBank were aligned and distance analyses were performed. All the samples were confirmed to belong to CLAS and group together with other sequences from the rest of the world. The Argentinean sequences did not all group together which could indicate different origins for the Argentinean strains. Further studies using different genes must been conducted, because the 16S rRNA region is a conservative region and does not allow definition of intra-specific groups.