Abstract

FLORES-DE LA ROSA, Felipe Roberto; RODRIGUEZ-QUIBRERA, Cynthia Guadalupe  and  SANTILLAN-MENDOZA, Ricardo. Phylogeny of ATP/ADP translocase gene from Candidatus Liberibacter spp., causal agents of HLB. Rev. mex. fitopatol [online]. 2021, vol.39, n.1, pp.219-227.  Epub May 07, 2021. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.2009-1.

The bacteria that cause citrus huanglongbing (HLB), Candidatus Liberibacter spp., are obligate bacteria to the citrus phloem and to different systems of the vector insect, Diaphorina citri, therefore, the genomic approach has been useful to study its pathogenicity mechanisms. This approach has allowed the identification of a homologous copy of the gene coding for the enzyme ATP / ADP translocase, which has the ability to import ATP and nucleotides from the host, causing considerable energy parasitism. This enzyme has been related to the endoparasitic activity of animal and human pathogens more than to phytopathogens. The present work analyzed the evolutionary relationship between the amino acid sequence of ATP / ADP translocase between different species of Ca. Liberibacter and groups such as Ricketssia sp. and Chlamydia sp. Phylogenetic analyzes show that the variation in the sequence of the gene coding for the enzyme is delimited in clades corresponding to the species of Ca. Liberibacter, suggesting that the variation in the enzyme responds to a co-evolutionary process. Also, the phylogeny shows that the closest common ancestor to Ca. Liberibacter could be a non-pathogenic endosymbiont of the genus Ca. Midichloria. Amino acid sequence conservation analysis shows that there are several positions in the sequence that could be related to species variation. The present work offers the hypothesis that the evolutionary origin of the energy parasitism capacity of the causal agents of HLB is a non-pathogenic endosymbiont.

Keywords : coevolution; energy parasitism; citrus greening.