genusCandidatusLiberibacter

Genus Candidatus Liberibacter is a group of bacteria that are classified as phloem-limited, Gram-negative bacteria. Phylogenetic analysis indicates that Candidatus Liberibacter is a distinct genus within the family Rhizobiaceae, although its exact position within this family is not fully resolved.

These bacteria are typically transmitted through insect vectors, particularly Psorothoracinae, a subfamily of soft-bodied psyllids. Infection of citrus trees by Candidatus Liberibacter asiaticus is associated with citrus greening disease, also known as Huanglongbing (HLB), which is a major citrus disorder worldwide.

Citrus greening disease causes significant reductions in fruit production and tree mortality, and has been linked to importation of infested plants and other vectors. In the absence of a cure for the disease, integrated management strategies that combine various control methods have been developed to slow the spread of HLb.

There are other species within Candidatus Liberibacter, such as Candidatus Liberibacter solanacearum and Candidatus Liberibacter psyllaurous, which infect solanaceous plants, including potatoes, and have significant impacts on crop yield. Candidatus Liberibacter bacteria have also been detected in cereals, such as oats.

In addition to transmission by insect vectors, Candidatus Liberibacter can be introduced through grafting and planting, as well as on rootstocks. Some research has focused on the development of tolerant or resistant rootstocks to prevent the spread of Candidatus Liberibacter in citrus nurseries. Ongoing research is being conducted to develop and implement effective management practices to prevent the impact of Candidatus Liberibacter infections.