Comparative transcriptomics and host-specific parasite gene expression profiles inform on drivers of proliferative kidney disease

Abstract

The myxozoan parasite, Tetracapsuloides bryosalmonae has a two-host life cycle alternating between freshwater bryozoans and salmonid fish. Infected fish can develop Proliferative Kidney Disease (PKD), characterised by a gross lymphoid-driven kidney pathology in wild and farmed salmonids. To facilitate an in-depth understanding of T. bryosalmonae-host interactions, we have adopted a two-host parasite transcriptome sequencing approach to minimize host contamination in the absence of a complete T. bryosalmonae genome. Parasite contigs common to both infected hosts (the intersect transcriptome; 7,362 contigs) were typically AT-rich (60-75% AT). 5,432 contigs within the intersect were annotated with 1,930 unannotatde contigs encoding for unknown transcripts. We have focused on transcripts encoding proteins involved in; nutrient acquisition, host-parasite interactions, development, and cell-to-cell communication or proteins of unknown function, establishing their potential importance in each host by RT-qPCR. Host-specific expression profiles were evident, particularly in transcripts encoding proteases and proteins involved in lipid metabolism, cell adhesion, and development. We confirm for the first time the presence of homeobox proteins and a frizzled homologue in myxozoan parasites.The novel insights into myxozoan biology that this study reveals will help to focus research in developing future disease control strategies.

Know your enemy – transcriptome of myxozoanTetracapsuloides bryosalmonaereveals potential drug targets against proliferative kidney disease in salmonids

“…In order to find the overlap between our T. bryosalmonae transcriptome and the recently reported T. bryosalmonae intersect transcriptome (from the dead-end vertebrate host, rainbow trout [O. mykiss], and the bryozoan F. sultana; Faber et al, 2021), we carried out reciprocal BLASTN. A transcript (longest isoform in case of multiple isoforms) was considered as present in Faber et al (2021) transcriptome if its top hit (95% minimum identity) matched the best hit in the reciprocal BLASTN. As the scaffolds in Faber et al (2021) transcriptome were relatively long (N50 = 2479) compared to ours (N50 = 657), for the reciprocal BLASTN, we allowed up to 3 hits per scaffold when Faber et al (2021) transcriptome was queried against our transcripts.…”

“…A transcript (longest isoform in case of multiple isoforms) was considered as present in Faber et al (2021) transcriptome if its top hit (95% minimum identity) matched the best hit in the reciprocal BLASTN. As the scaffolds in Faber et al (2021) transcriptome were relatively long (N50 = 2479) compared to ours (N50 = 657), for the reciprocal BLASTN, we allowed up to 3 hits per scaffold when Faber et al (2021) transcriptome was queried against our transcripts. All isoforms of the same gene were considered as present if the longest isoform was present in Faber et al (2021) transcriptome and vice versa.…”

“…As the scaffolds in Faber et al (2021) transcriptome were relatively long (N50 = 2479) compared to ours (N50 = 657), for the reciprocal BLASTN, we allowed up to 3 hits per scaffold when Faber et al (2021) transcriptome was queried against our transcripts. All isoforms of the same gene were considered as present if the longest isoform was present in Faber et al (2021) transcriptome and vice versa. The GO terms between the genes found in Faber et al (2021) transcriptome vs the genes unique to our study were compared using WEGO 2 (Ye et al, 2018).…”

“…All isoforms of the same gene were considered as present if the longest isoform was present in Faber et al (2021) transcriptome and vice versa. The GO terms between the genes found in Faber et al (2021) transcriptome vs the genes unique to our study were compared using WEGO 2 (Ye et al, 2018).…”

Serine protease inhibitors of the whirling disease parasite Myxobolus cerebralis (Cnidaria, Myxozoa): Expression profiling and functional predictions

“…It has been proven that GAPDH was the most uniformly expressed gene across the different developmental stages of M. cerebralis [55]. Although the suitability of RPL18 was not confirmed on the given species, it was used previously as a reliable reference gene for studying gene expression in Tetracapsuloides bryosalmonae causing proliferative kidney disease of salmonids [56,57]. The obtained relative expression profiles of the examined four M. cerebralis serpins showed three different patterns.…”