title: Evidence that a laminin-like insect protein mediates early events in the interaction of a Phytoparasite with its vector's salivary gland.
abstract: Phytomonas species are plant parasites of the family Trypanosomatidae, which are transmitted by phytophagous insects. Some Phytomonas species cause major agricultural damages. The hemipteran Oncopeltus fasciatus is natural and experimental host for several species of trypanosomatids, including Phytomonas spp. The invasion of the insect vectors' salivary glands is one of the most important events for the life cycle of Phytomonas species. In the present study, we show the binding of Phytomonas serpens at the external face of O. fasciatus salivary glands by means of scanning electron microscopy and the in vitro interaction of living parasites with total proteins from the salivary glands in ligand blotting assays. This binding occurs primarily through an interaction with a 130 kDa salivary gland protein. The mass spectrometry of the trypsin-digest of this protein matched 23% of human laminin-5 β3 chain precursor sequence by 16 digested peptides. A protein sequence search through the transcriptome of O. fasciatus embryo showed a partial sequence with 51% similarity to human laminin β3 subunit. Anti-human laminin-5 β3 chain polyclonal antibodies recognized the 130 kDa protein by immunoblotting. The association of parasites with the salivary glands was strongly inhibited by human laminin-5, by the purified 130 kDa insect protein, and by polyclonal antibodies raised against the human laminin-5 β3 chain. This is the first report demonstrating that a laminin-like molecule from the salivary gland of O. fasciatus acts as a receptor for Phytomonas binding. The results presented in this investigation are important findings that will support further studies that aim at developing new approaches to prevent the transmission of Phytomonas species from insects to plants and vice-versa.
authors.affiliation: Instituto de Microbiologia Paulo de Goes, UFRJ, Ilha do Fundao, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: de Almeida Dias
authors.forename: Andre Luis
authors.initials: AL
authors.lastname: Souza dos Santos
authors.forename: Letícia Miranda
authors.initials: LM
authors.lastname: Santos Lery
authors.forename: Thiago Luiz
authors.initials: TL
authors.lastname: Alves e Silva
authors.forename: Mauricio Martins
authors.initials: MM
authors.lastname: Oliveira
authors.forename: Paulo Mascarello
authors.initials: PM
authors.lastname: Bisch
authors.forename: Elvira Maria
authors.initials: EM
authors.lastname: Saraiva
authors.forename: Thaïs Cristina
authors.initials: TC
authors.lastname: Souto-Padrón
authors.forename: Angela Hampshire
authors.initials: AH
authors.lastname: Lopes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000276:immunology / Q000494:pharmacology; D020062:Heteroptera / Q000469:parasitology*; D006790:Host-Parasite Interactions / Q000187:drug effects; D006801:Humans; D019476:Insect Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D007303:Insect Vectors / Q000469:parasitology*; D007797:Laminin / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000469:parasitology; D011485:Protein Binding; D012469:Salivary Glands / Q000378:metabolism* / Q000469:parasitology / Q000648:ultrastructure; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014351:Trypanosomatina / Q000502:physiology*; D000097794:Kalinin
chemical_list: D000906:Antibodies; D015815:Cell Adhesion Molecules; D019476:Insect Proteins; D007797:Laminin; D000097794:Kalinin