Congopain genes diverged to become specific to Savannah, Forest and Kilifi subgroups of Trypanosoma congolense, and are valuable for diagnosis, genotyping and phylogenetic inferences.
Trypanosoma congolense is the most important agent of nagana, a wasting livestock trypanosomosis in sub-Saharan Africa. This species is a complex of three subgroups (Savannah, Forest and Kilifi) that differ in virulence, pathogenicity, drug resistance, vectors, and geographical distribution. Congopain, the major Cathepsin L-like cysteine protease (CP2) of T. congolense, has been extensively investigated as a pathogenic factor and target for drugs and vaccines, but knowledge about this enzyme is mostly restricted to the reference strain IL3000, which belongs to the Savannah subgroup. In this work we compared sequences of congopain genes from IL3000 genome database and isolates of the three subgroups of T. congolense. Results demonstrated that the congopain genes diverged into three subclades consistent with the three subgroups within T. congolense. Laboratory and field isolates of Savannah exhibited a highly polymorphic repertoire both inter- and intra-isolates: sequences sharing the archetypical catalytic triad clustered into SAV1-SAV3 groups, whereas polymorphic sequences that, in general, exhibited unusual catalytic triad (variants) assigned to SAV4 or not assigned to any group. Congopain homologous genes from Forest and Kilifi isolates showed, respectively, moderate and limited diversity. In the phylogenetic tree based on congopain and homologues, Savannah was closer to Forest than to Kilifi. All T. congolense subgroup nested into a single clade, which together with the sister clade formed by homologues from Trypanosoma simiae and Trypanosoma godfreyi formed a clade supporting the subgenus Nannomonas. A single PCR targeting congopain sequences was developed for the diagnosis of T. congolense isolates of the three subgroups. Our findings demonstrated that congopain genes are valuable targets for the diagnosis, genotyping, and phylogenetic and taxonomic inferences among T. congolense isolates and other members of the subgenus Nannomonas.
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Adriana C
AC
Rodrigues
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Paola A
PA
Ortiz
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
André G
AG
Costa-Martins
Biotechnology Centre, Eduardo Mondlane University, Maputo, Mozambique; Faculty of Veterinary Science, University of Pretoria, South Africa.
Luis
L
Neves
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Department of Veterinary Pathology, Faculty of Veterinary Sciences, Central University of Venezuela, Maracay, Venezuela.
Herakles A
HA
Garcia
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
João M P
JM
Alves
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Erney P
EP
Camargo
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Silvia C
SC
Alfieri
School of Biological Sciences, University of Bristol, Bristol BS8 1UG, United Kingdom.
Wendy
W
Gibson
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil. Electronic address: mmgteix@icb.usp.br.
Marta M G
MM
Teixeira
D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D014644:Genetic Variation; D018503:Genome, Protozoan; D005838:Genotype; D058889:Molecular Typing / Q000379:methods*; D010802:Phylogeny; D013045:Species Specificity; D014348:Trypanosoma congolense / Q000145:classification* / Q000235:genetics*; D014353:Trypanosomiasis, African / Q000175:diagnosis
D003546:Cysteine Endopeptidases; C084086:congopain
Congopain; Forest; Genotyping; Kilifi; Savannah; Trypanosoma congolense