'Candidatus Liberibacter' Pathosystems at the Forefront of Agricultural and Biological Research Challenges

Authors: PIERSON, ELIZABETH - Texas A&M University; ROPER, CAROLINE - University Of California; BROWN, JUDITH - University Of Arizona; Bock, Clive; WANG, NIAN - University Of Florida

Submitted to: Phytopathology
Publication Type: Other
Publication Acceptance Date: 1/15/2022
Publication Date: 1/31/2022
Citation: Pierson, E.A., Roper, C., Brown, J.K., Bock, C.H., Wang, N. 2022. 'Candidatus Liberibacter' Pathosystems at the Forefront of Agricultural and Biological Research Challenges. Phytopathology. Vol 112: 7-10. https://doi.org/10.1094/PHYTO-12-21-0497-FI.
DOI: https://doi.org/10.1094/PHYTO-12-21-0497-FI

Interpretive Summary:

Technical Abstract: Candidatus Liberibacter (Ca. L.) species are Gram-negative, phloem-colonizing, psyllid-transmitted fastidious bacteria, classified in the Rhizobiaceae (Class: Alphaproteobacteria). Thus far, seven Liberibacter species have been identified worldwide. They infect a range of crop species. Ca. L. asiaticus (CLas), Ca. L. africanus (CLaf), and Ca. L. americanus (CLam) are the causal agents of citrus Huanglongbing (HLB) or citrus greening disease, which is the most devastating citrus disease worldwide. CLas and Clam are transmitted by the Asian citrus psyllid Diaphorina citri Kuwayama, and Claf by the African citrus psyllid, Trioza erytreae Del Guercio. Other species of Ca. L. on other host species are vectored by other psyllid species. The economic importance of newly discovered and/or apparently geographically expanding Ca. L. plant diseases in a number of locales worldwide has attracted tremendous attention from producers, the public, the scientific community, and government agencies. The attention has elevated Ca. L. pathosystem to the forefront of investigation among plant pathogens, and specifically in the plant pathogen-insect vector arena. Thus, exciting new insights are eagerly anticipated from research into biological, genetic, genomic, and evolutionary aspects of Ca. Liberibacter-plant-psyllid interactions. Given the economic importance, broad impact on plant pathology, and potential importance of better management based on new knowledge of Ca. Liberibacter-plant-insect interactions, Phytopathology was compelled to select Ca. Liberibacter pathosystems as the topic for the January 2022 Focus Issue. We hope this focus issue will be a useful and valuable resource of information and inspiration for future research in Ca. Liberibacter-disease management, with the realization that effective control relies on new discoveries and a greater understanding of multiple facets of Ca. Liberibacter pathosystems that remain poorly understood.