Functional characterization of LotP from L iberibacter asiaticus

• Published in: Microbial biotechnology Vol. 10; no. 3; pp. 642 - 656
• Main Authors: Loto, Flavia, Coyle, Janelle F., Padgett, Kaylie A., Pagliai, Fernando A., Gardner, Christopher L., Lorca, Graciela L., Gonzalez, Claudio F.
• Format: Journal Article
• Language: English
• Published: Bedford John Wiley & Sons, Inc 01-05-2017
• Subjects: Adenosine triphosphatase; Bacteria; Bacterial diseases; Biochemical characteristics; Biochemistry; Citrus fruits; Citrus greening; Citrus trees; Cultivars; Deoxyribonucleic acid; Dimers; DNA; E coli; Electrophoretic mobility; Fruit trees; Gene expression; Genomes; High temperature; Hybrid systems; Immunoprecipitation; Infections; Insects; Lon protein; Molecular weight; Organisms; Osmolarity; Osmotic stress; Phylogenetics; Plant diseases; Proteins; Statistical analysis; Variance analysis; United States > US; Massachusetts
• ISSN: 1751-7915; 1751-7915
• DOI: 10.1111/1751-7915.12706

Liberibacter asiaticus
is an unculturable parasitic bacterium of the alphaproteobacteria group hosted by both citrus plants and a psyllid insect vector (
Diaphorina citri
). In the citrus tree, the bacteria thrive only inside the phloem, causing a systemically incurable and deadly plant disease named citrus greening or Huanglongbing. Currently, all commercial citrus cultivars in production are susceptible to
L. asiaticus
, representing a serious threat to the citrus industry worldwide. The technical inability to isolate and culture
L. asiaticus
has hindered progress in understanding the biology of this bacterium directly. Consequently, a deep understanding of the biological pathways involved in the regulation of host–pathogen interactions becomes critical to rationally design future and necessary strategies of control. In this work, we used surrogate strains to evaluate the biochemical characteristics and biological significance of
CLIBASIA
_03135. This gene, highly induced during early stages of plant infection, encodes a 23
kD
a protein and was renamed in this work as LotP. This protein belongs to an uncharacterized family of proteins with an overall structure resembling the
LON
protease N‐terminus. Co‐immunoprecipitation assays allowed us to identify the
Liberibacter
chaperonin Gro
EL
as the main LotP‐interacting protein. The specific interaction between LotP and Gro
EL
was reconstructed and confirmed using a two‐hybrid system in
Escherichia coli
. Furthermore, it was demonstrated that LotP has a native molecular weight of 44
kD
a, corresponding to a dimer in solution with
ATP
ase activity
in vitro
. In
Liberibacter crescens
, LotP is strongly induced in response to conditions with high osmolarity but repressed at high temperatures. Electrophoretic mobility shift assay (
EMSA
) results suggest that LotP is a member of the LdtR regulon and could play an important role in tolerance to osmotic stress.