Population genomics of the obligate phytopathogen Candidatus Liberibacter asiaticus

• Grant number: 24/18844-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: Filipe Pereira Matteoli
• Grantee: Anna Julia Chen
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Environmental bacteria develop multiple ecological relationships with plants, ranging from phytopathogenesis to plant growth promotion. Candidatus Liberibacter asiaticus (CLas) is an environmental bacterium that unable to be cultivated due to its obligate intracellular lifestyle. In citrus, CLas is the etiological agent of Huanglongbing disease (HLB), a scourge that causes significant impacts to producers of this important agricultural commodity. It infects plants via an invertebrate host, the psyllid Diaphorina citri. Although HLB is widely known for its devastating effects on citrus, it is mostly managed through practices aimed at containing the infection or dispersal of the insect vector as little is known about the molecular mechanisms involved in the plant infection. In recent years, due to the popularization of long-read sequencing methods, it has become possible to obtain high-quality metagenome-assembled genomes (MAGs). Since then, bioinformatic analyses of MAGs from different Candidatus Liberibacter species, along with genomes from the culturable species Liberibacter crescens, are unraveling aspects of the biology and evolution of this elusive group of prokaryotes. Despite these advances, no study has addressed the population genomics features of the group's major phytopathogen, the CLas bacterium. Therefore, we propose to conduct the first large-scale study of Candidatus Liberibacter asiaticus by analyzing all 36 public MAGs available in the RefSeq database for this species. We seek to characterize the pangenome, and to assess the distribution and conservation of genes associated with the phytopathogenic lifestyle, such as: Sec-translocon systems, prophage regions, plasmid regions, and genes tad. The results will allow us to expand the understanding of the molecular mechanisms involved in the interaction between CLas and plants.