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Comparative genomic analysis of three Leishmania species that cause diverse human disease.

ABSTRACT: Leishmania parasites cause a broad spectrum of clinical disease. Here we report the sequencing of the genomes of two species of Leishmania: Leishmania infantum and Leishmania braziliensis. The comparison of these sequences with the published genome of Leishmania major reveals marked conservation of synteny and identifies only approximately 200 genes with a differential distribution between the three species. L. braziliensis, contrary to Leishmania species examined so far, possesses components of a putative RNA-mediated interference pathway, telomere-associated transposable elements and spliced leader-associated SLACS retrotransposons. We show that pseudogene formation and gene loss are the principal forces shaping the different genomes. Genes that are differentially distributed between the species encode proteins implicated in host-pathogen interactions and parasite survival in the macrophage.

SUBMITTER: Peacock CS

PROVIDER: S-EPMC2592530 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature

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Comparative genomic analysis of three Leishmania species that cause diverse human disease.

Peacock Christopher S CS Seeger Kathy K Harris David D Murphy Lee L Ruiz Jeronimo C JC Quail Michael A MA Peters Nick N Adlem Ellen E Tivey Adrian A Aslett Martin M Kerhornou Arnaud A Ivens Alasdair A Fraser Audrey A Rajandream Marie-Adele MA Carver Tim T Norbertczak Halina H Chillingworth Tracey T Hance Zahra Z Jagels Kay K Moule Sharon S Ormond Doug D Rutter Simon S Squares Rob R Whitehead Sally S Rabbinowitsch Ester E Arrowsmith Claire C White Brian B Thurston Scott S Bringaud Frédéric F Baldauf Sandra L SL Faulconbridge Adam A Jeffares Daniel D Depledge Daniel P DP Oyola Samuel O SO Hilley James D JD Brito Loislene O LO Tosi Luiz R O LR Barrell Barclay B Cruz Angela K AK Mottram Jeremy C JC Smith Deborah F DF Berriman Matthew M

Nature genetics 20070617 7

Leishmania parasites cause a broad spectrum of clinical disease. Here we report the sequencing of the genomes of two species of Leishmania: Leishmania infantum and Leishmania braziliensis. The comparison of these sequences with the published genome of Leishmania major reveals marked conservation of synteny and identifies only approximately 200 genes with a differential distribution between the three species. L. braziliensis, contrary to Leishmania species examined so far, possesses components of ...[more]

PMID: 17572675

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Project description:BackgroundThe Leishmania (Viannia) braziliensis complex is responsible for most cases of New World tegumentary leishmaniasis. This complex includes two closely related species but with different geographic distribution and disease phenotypes, L. (V.) peruviana and L. (V.) braziliensis. However, the genetic basis of these differences is not well understood and the status of L. (V.) peruviana as distinct species has been questioned by some. Here we sequenced the genomes of two L. (V.) peruviana isolates (LEM1537 and PAB-4377) using Illumina high throughput sequencing and performed comparative analyses against the L. (V.) braziliensis M2904 reference genome. Comparisons were focused on the detection of Single Nucleotide Polymorphisms (SNPs), insertions and deletions (INDELs), aneuploidy and gene copy number variations.ResultsWe found 94,070 variants shared by both L. (V.) peruviana isolates (144,079 in PAB-4377 and 136,946 in LEM1537) against the L. (V.) braziliensis M2904 reference genome while only 26,853 variants separated both L. (V.) peruviana genomes. Analysis in coding sequences detected 26,750 SNPs and 1,513 indels shared by both L. (V.) peruviana isolates against L. (V.) braziliensis M2904 and revealed two L. (V.) braziliensis pseudogenes that are likely to have coding potential in L. (V.) peruviana. Chromosomal read density and allele frequency profiling showed a heterogeneous pattern of aneuploidy with an overall disomic tendency in both L. (V.) peruviana isolates, in contrast with a trisomic pattern in the L. (V.) braziliensis M2904 reference. Read depth analysis allowed us to detect more than 368 gene expansions and 14 expanded gene arrays in L. (V.) peruviana, and the likely absence of expanded amastin gene arrays.ConclusionsThe greater numbers of interspecific SNP/indel differences between L. (V.) peruviana and L. (V.) braziliensis and the presence of different gene and chromosome copy number variations support the classification of both organisms as closely related but distinct species. The extensive nucleotide polymorphisms and differences in gene and chromosome copy numbers in L. (V.) peruviana suggests the possibility that these may contribute to some of the unique features of its biology, including a lower pathology and lack of mucosal development.

Project description:The genomic DNAs of strains JPCM5 and 263 of L. infantum, strains LV39 and Friedlin of L. major and strains Parrot-TarII and S125 of L. tarentolae were used in comparative genomic hybridizations to reveal the intra-species and inter-species gene content, and to validate L. tarentolae Parrot-TarII genome sequencing results. Leishmania (Sauroleishmania) tarentolae was first isolated in the lizard Tarentola mauritanica. This species is not known to be pathogenic to humans but is often used as a model organism for molecular analyses or protein overproduction. The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved by high-throughput sequencing technologies. The L. tarentolae genome was first assembled de novo and then aligned against the reference L. major Friedlin genome to facilitate contig positioning and annotation, providing a 23-fold coverage of the genome. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described, and it provides an opportunity for comparison with the completed genomes of the pathogenic Leishmania species. A high synteny was observed in de novo assembled contigs between all sequenced Leishmania species. A number of limited chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic with L. major. Globally, over 90% of the L. tarentolae gene content was shared with the other Leishmania species. There were 250 L. major genes absent from L. tarentolae, and interestingly these missing genes were primarily expressed in the intracellular amastigote stage of the pathogenic parasites. This implies that L. tarentolae may have impaired ability to survive as an intracellular parasite. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the leishmanolysin (GP63) and a gene related to the promastigote surface antigen (PSA31C). Overall, L. tarentolae appears to have a gene content more adapted to the insect stage rather than the mammalian one. This may partly explain its inability to replicate within mammalian macrophages and its suspected preferred life style as promastigote in the lizards.

Project description:The three common intestinal Cryptosporidium species in cattle differ significantly in host range, pathogenicity and public health significance. While Cryptosporidium parvum is pathogenic in pre-weaned calves and has a broad host range, C. bovis and C. ryanae are largely non-pathogenic and bovine-specific species in post-weaned calves. Thus far, only the genome of C. parvum has been sequenced. To improve our understanding of the genetic determinants of biological differences among Cryptosporidium spcies, we sequenced the genomes of C. bovis and C. ryanae and conducted a comparative genomics analysis. The genome of C. bovis has a gene content and organization more similar to C. ryanae than to other Cryptosporidium species sequenced to date; the level of similarity in amino acid and nucleotide sequences between the two species is 75.2 and 69.4?%, respectively. A total of 3723 and 3711 putative protein-encoding genes were identified in the genomes of C. bovis and C. ryanae, respectively, which are fewer than the 3981 in C. parvum. Metabolism is similar among the three species, although energy production pathways are further reduced in C. bovis and C. ryanae. Compared with C. parvum, C. bovis and C. ryanae have lost 14 genes encoding mucin-type glycoproteins and three for insulinase-like proteases. Other gene gains and losses in the two bovine-specific and non-pathogenic species also involve the secretory pathogenesis determinants (SPDs); they have lost all genes encoding MEDLE, FLGN and SKSR proteins, and two of the three genes for NFDQ proteins, but have more genes encoding secreted WYLE proteins, secreted leucine-rich proteins and GPI-anchored adhesin PGA18. The only major difference between C. bovis and C. ryanae is in nucleotide metabolism. In addition, half of the highly divergent genes between C. bovis and C. ryanae encode secreted or membrane-bound proteins. Therefore, C. bovis and C. ryanae have gene organization and metabolic pathways similar to C. parvum, but have lost some invasion-associated mucin glycoproteins, insulinase-like proteases, MEDLE secretory proteins and other SPDs. The multiple gene families under positive selection, such as helicase-associated domains, AMP-binding domains, protein kinases, mucins, insulinases and TRAPs could contribute to differences in host specificity and pathogenicity between C. parvum and C. bovis. Biological studies should be conducted to assess the contribution of these copy number variations to the narrow host range and reduced pathogenicity of C. bovis and C. ryanae.

Project description:Aphids are phloem-feeding insects that cause significant economic losses to agriculture worldwide. While feeding and probing these insects deliver molecules, called effectors, inside their host to enable infestation. The identification and characterization of these effectors from different species that vary in their host range is an important step in understanding the infestation success of aphids and aphid host range variation. This study employs a multi-disciplinary approach based on transcriptome sequencing and proteomics to identify and compare effector candidates from the broad host range aphid Myzus persicae (green peach aphid) (genotypes O, J and F), and narrow host range aphids Myzus cerasi (black cherry aphid) and Rhopalosiphum padi (bird-cherry oat aphid).Using a combination of aphid transcriptome sequencing on libraries derived from head versus body tissues as well as saliva proteomics we were able to predict candidate effectors repertoires from the different aphid species and genotypes. Among the identified conserved or core effector sets, we identified a significant number of previously identified aphid candidate effectors indicating these proteins may be involved in general infestation strategies. Moreover, we identified aphid candidate effector sequences that were specific to one species, which are interesting candidates for further validation and characterization with regards to species-specific functions during infestation. We assessed our candidate effector repertoires for evidence of positive selection, and identified 49 candidates with DN/DS ratios >1. We noted higher rates of DN/DS ratios in predicted aphid effectors than non-effectors. Whether this reflects positive selection due to co-evolution with host plants, or increased neofunctionalization upon gene duplication remains to be investigated.Our work provides a comprehensive overview of the candidate effector repertoires from three different aphid species with varying host ranges. Comparative analyses revealed candidate effectors that are most likely are involved in general aspects of infestation, whereas others, that are highly divergent, may be involved in specific processes important for certain aphid species. Insights into the overlap and differences in aphid effector repertoires are important in understanding how different species successfully infest different ranges of plant species.

Dataset Information

Comparative genomic analysis of three Leishmania species that cause diverse human disease.

Publications

Comparative genomic analysis of three Leishmania species that cause diverse human disease.

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