title: The putative RxLR effector protein SpHtp1 from the fish pathogenic oomycete Saprolegnia parasitica is translocated into fish cells.
abstract: The fish pathogenic oomycete Saprolegnia parasitica causes the disease Saprolegniosis in salmonids and other freshwater fish, resulting in considerable economic losses in aquaculture. Very little is known about the molecular and cellular mechanisms underlying the infection process of fish pathogenic oomycetes. In order to investigate the interaction in detail, an in vitro infection assay using an Oncorhynchus mykiss (rainbow trout) cell line (RTG-2) was developed. In a zoospore/cyst cDNA library, we identified the ORF SpHtp1, which encodes a secreted protein containing an RxLR motif. Detailed expression analysis indicated that SpHtp1 is highly expressed in zoospores/cysts from S. parasitica and in the very early stages of infection on RTG-2 cells, when compared with in vitro-grown mycelium. Moreover, the protein, SpHtp1, was found to translocate into the RTG-2 trout cells, during the interaction with S. parasitica, and also when the RTG-2 cells were treated with recombinant SpHtp1 fused to a C-terminal His-tag. These findings suggest that protein translocation could play an important role in Saprolegniosis.
authors.affiliation: Aberdeen Oomycete Laboratory, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen - School of Medical Sciences, Foresterhill, Aberdeen, UK. p.vanwest@abdn.ac.uk
authors.forename: Pieter
authors.initials: P
authors.lastname: van West
authors.forename: Irene
authors.initials: I
authors.lastname: de Bruijn
authors.forename: Kirsty L
authors.initials: KL
authors.lastname: Minor
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Phillips
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Robertson
authors.forename: Stephan
authors.initials: S
authors.lastname: Wawra
authors.forename: Judith
authors.initials: J
authors.lastname: Bain
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Anderson
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Secombes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D005393:Fish Diseases / Q000469:parasitology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006790:Host-Parasite Interactions / Q000502:physiology; D007239:Infections / Q000469:parasitology*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000469:parasitology*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044762:Saprolegnia / Q000235:genetics / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins