Identification and characterization of the merozoite surface protein 1 (msp1) gene in a host-generalist avian malaria parasite, Plasmodium relictum (lineages SGS1 and GRW4) with the use of blood transcriptome

Abstract

BackgroundThe merozoite surface protein 1 (msp1) is one of the most studied vaccine candidate genes in mammalian Plasmodium spp. to have been used for investigations of epidemiology, population structures, and immunity to infections. However methodological difficulties have impeded the use of nuclear markers such as msp1 in Plasmodium parasites causing avian malaria. Data from an infection transcriptome of the host generalist avian malaria parasite Plasmodium relictum was used to identify and characterize the msp1 gene from two different isolates (mtDNA lineages SGS1 and GRW4). The aim was to investigate whether the msp1 gene in avian malaria species shares the properties of the msp1 gene in Plasmodium falciparum in terms of block variability, conserved anchor points and repeat motifs, and further to investigate the degree to which the gene might be informative in avian malaria parasites for population and epidemiological studies.MethodsReads from 454 sequencing of birds infected with avian malaria was used to develop Sanger sequencing protocols for the msp1 gene of P. relictum. Genetic variability between variable and conserved blocks of the gene was compared within and between avian malaria parasite species, including P. falciparum. Genetic variability of the msp1 gene in P. relictum was compared with six other nuclear genes and the mtDNA gene cytochrome b.ResultsThe msp1 gene of P. relictum shares the same general pattern of variable and conserved blocks as found in P. falciparum, although the variable blocks exhibited less variability than P. falciparum. The variation across the gene blocks in P. falciparum spanned from being as conserved as within species variation in P. relictum to being as variable as between the two avian malaria species (P. relictum and Plasmodium gallinaceum) in the variable blocks. In P. relictum the highly conserved p19 region of the peptide was identified, which included two epidermal growth factor-like domains and a fully conserved GPI anchor point.ConclusionThis study provides protocols for evaluation of the msp1 gene in the avian malaria generalist parasite P. relictum. The msp1 gene in avian Plasmodium shares the genetic properties seen in P. falciparum, indicating evolutionary conserved functions for the gene. The data on the variable blocks of the gene show that the msp1 gene in P. relictum might serve as a good candidate gene for future population and epidemiological studies of the parasite.

Differences in host species relationships and biogeographic influences produce contrasting patterns of prevalence, community composition and genetic structure in two genera of avian malaria parasites in southern Melanesia

“…Furthermore, the current molecular markers applied to haemosporidian lineages describe variation at a coarse scale, and the development of more variable genetic markers (Hellgren et al . ) will undoubtedly improve resolution of spatial and host patterns in the region.…”

Detecting transmission areas of malaria parasites in a migratory bird species

“…The data on the distribution of nuclear MSP1 alleles across the cyt b lineages may facilitate the investigation on the distribution of these malaria parasites across geographical regions (Hellgren et al 2013(Hellgren et al , 2015. A recent study has explored the global phylogeography of the P. relictum based on MSP1 allelic diversity, showing several different MSP1 alleles within the cyt b lineages of SGS1 and GRW4.…”

“…Diluted genomic DNA (25 ng/μL) was used as a template in a polymerase chain reaction (PCR) assay for detection of the parasites using nested PCRprotocols described by Waldenström et al (2004). We selected SGS1 and GRW4 infected house martins for further analyses of the MSP1 gene (270 nucleotides, block 14) and detect the MSP1 allele following the protocol described by Hellgren et al (2013) and using the primers MSP1_3F, MSP1_3R, MSP1_3FN and MSP1_3RN. All PCR experiments contained one negative control for every eight samples.…”

Delineation of the Genera Haemoproteus and Plasmodium Using RNA-Seq and Multi-gene Phylogenetics

“…While valuable, this kind of analysis lacks the depth necessary to answer important questions regarding parasite relationships (Hellgren et al 2013; Outlaw and Ricklefs 2014; Borner et al 2016; Bensch et al 2016). Unresolved phylogenetic relationships can be addressed with multi-gene datasets (Borner et al 2016).…”