Dataset Information

Evidence for diversifying selection of genetic regions of encoding putative collagen-like host-adhesive fibers in Pasteuria penetrans.

ABSTRACT: Pasteuria spp. belong to a group of genetically diverse endospore-forming bacteria (phylum: Firmicutes) that are known to parasitize plant-parasitic nematodes and water fleas (Daphnia spp.). Collagen-like fibres form the nap on the surface of endospores and the genes encoding these sequences have been hypothesised to be involved in the adhesion of the endospores of Pasteuria spp. to their hosts. We report a group of 17 unique collagen-like genes putatively encoded by Pasteuria penetrans (strain: Res148) that formed five different phylogenetic clusters and suggest that collagen-like proteins are an important source of genetic diversity in animal pathogenic Firmicutes including Pasteuria. Additionally, and unexpectedly, we identified a putative collagen-like sequence which had a very different sequence structure to the other collagen-like proteins but was similar to the protein sequences in Megaviruses that are involved in host-parasite interactions. We, therefore, suggest that these diverse endospore surface proteins in Pasteuria are involved in biological functions, such as cellular adhesion; however, they are not of monophyletic origin and were possibly obtained de novo by mutation or possibly through selection acting upon several historic horizontal gene transfer events.

SUBMITTER: Srivastava A

PROVIDER: S-EPMC6238073 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundSouthern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment.ResultsA total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle.ConclusionsHere we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.

Project description:AimsPhytonematodes are a constraint on crop production and have been controlled using nematicides; these are highly toxic and legislation in Europe and elsewhere is prohibiting their use and alternatives are being sought. Pasteuria penetrans is a hyperparasitic bacterium that form endospores and have potential to control root-knot nematodes (Meloidogyne spp.), but their attachment to the nematode cuticle is host-specific. Understanding host specificity has relied upon endospore inhibition bioassays using immunological and biochemical approaches. Phylogenetic analysis of survey sequences has shown P. penetrans to be closely related to Bacillus and to have a diverse range of collagen-like fibres which we hypothesise to be involved in the endospore adhesion. However, due to the obligately hyperparasitic nature of Pasteuria species, identifying and characterizing these collagenous-like proteins through gain of function has proved difficult and new approaches are required.Methods and resultsUsing antibodies raised to synthetic peptides based on Pasteuria collagen-like genes we show similarities between P. penetrans and the more easily cultured bacterium Bacillus thuringiensis and suggest it be used as a gain of function platform/model. Using immunological approaches similar proteins between P. penetrans and B. thuringiensis are identified and characterized, one >250 kDa and another ~72 kDa are glycosylated with N-acetylglucosamine and both of which are digested if treated with collagenase. These treatments also affected endospore attachment and suggest these proteins are involved in adhesion of endospores to nematode cuticle.ConclusionThere are conserved similarities in the collagen-like proteins present on the surface of endospores of both P. penetrans and B. thuringiensis.Significance and impact of studyAs B. thuringiensis is relatively easy to culture and can be transformed, it could be developed as a platform for studying the role of the collagen-like adhesins from Pasteuria in endospore adhesion.

Dataset Information

Evidence for diversifying selection of genetic regions of encoding putative collagen-like host-adhesive fibers in Pasteuria penetrans.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets