Transcriptomic analysis of male and female Schistosoma mekongi adult worms

Orawan Phuphisut,Pravech Ajawatanawong,Dorn Watthanakulpanich,Supaporn Nuamtanong,Salisa Chaimon,Paron Dekumyoy,Yanin Limpanont,Sumate Ampawong,Poom Adisakwattana,Brett E Swierczewski,Onrapak Reamtong

doi:10.1186/s13071-018-3086-z

Abstract

BackgroundSchistosoma mekongi is one of five major causative agents of human schistosomiasis and is endemic to communities along the Mekong River in southern Lao People’s Democratic Republic (Laos) and northern Cambodia. Sporadic cases of schistosomiasis have been reported in travelers and immigrants who have visited endemic areas. Schistosoma mekongi biology and molecular biology is poorly understood, and few S. mekongi gene and transcript sequences are available in public databases.ResultsTranscriptome sequencing (RNA-Seq) of male and female S. mekongi adult worms (a total of three biological replicates for each sex) were analyzed and the results demonstrated that approximately 304.9 and 363.3 million high-quality clean reads with quality Q30 (> 90%) were obtained from male and female adult worms, respectively. A total of 119,604 contigs were assembled with an average length of 1273 nt and an N50 of 2017 nt. From the contigs, 20,798 annotated protein sequences and 48,256 annotated transcript sequences were obtained using BLASTP and BLASTX searches against the UniProt Trematoda database. A total of 4658 and 3509 transcripts were predominantly expressed in male and female worms, respectively. Male-biased transcripts were mostly involved in structural organization while female-biased transcripts were typically involved in cell differentiation and egg production. Interestingly, pathway enrichment analysis suggested that genes involved in the phosphatidylinositol signaling pathway may play important roles in the cellular processes and reproductive systems of S. mekongi worms.ConclusionsWe present comparative transcriptomic analyses of male and female S. mekongi adult worms, which provide a global view of the S. mekongi transcriptome as well as insights into differentially-expressed genes associated with each sex. This work provides valuable information and sequence resources for future studies of gene function and for ongoing whole genome sequencing efforts in S. mekongi.

Highlights

Schistosoma mekongi is one of five major causative agents of human schistosomiasis and is endemic to communities along the Mekong River in southern Lao People’s Democratic Republic (Laos) and northern Cambodia
Individuals infected by S. mekongi are mostly villagers living in endemic areas, but cases occur in immigrants who resettle in other countries
The assembly with k-mer size 31 was subsequently selected, due to its high realignment rate and higher N50 value, to filter redundant sequences. Summaries of both transcriptome assemblies’ quality and realignment rate are shown in Additional file 2: Table S1

Summary

Introduction

Schistosoma mekongi is one of five major causative agents of human schistosomiasis and is endemic to communities along the Mekong River in southern Lao People’s Democratic Republic (Laos) and northern Cambodia. Mekong schistosomiasis is an important human parasitic disease and is caused by infection with Schistosoma mekongi. The parasite is highly prevalent along the Mekong River in southern Lao People’s Democratic Republic (Laos) and northern Cambodia [1,2,3]. No effective vaccine against S. mekongi is available, and anthelmintic treatment relies upon a single drug, Phuphisut et al Parasites & Vectors (2018) 11:504 praziquantel, against which resistance is becoming occurrence in some areas [9,10,11,12,13]. Identification of novel targets for drug and vaccine development is urgently needed [14]

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