Diversity of Candidatus Liberibacter asiaticus, based on the omp gene sequence

Huanglongbing (yellow dragon disease) is a destructive disease of citrus. The etiological agent is a noncultured, phloem-restricted alpha-proteobacterium, Candidatus Liberibacter africanus in Africa and Candidatus Liberibacter asiaticus in Asia. In this study, we used an omp-based PCR-restriction fragment length polymorphism (RFLP) approach to analyze the genetic variability of Ca. Liberibacter asiaticus isolates. By using five different enzymes, each the 10 isolates tested could be associated with a specific combination of restriction profiles. The results indicate that the species Ca. Liberibacter asiaticus, even within a given region, may comprise several different variants. Thus, omp-based PCR-RFLP analysis is a simple method for detecting and differentiating Ca. Liberibacter asiaticus isolates.