title: Effects of potato plants expressing a barley cystatin on the predatory bug Podisus maculiventris via herbivorous prey feeding on the plant.
abstract: The aim of this study was to assess the effects of potato plants expressing a barley cystatin on a potentially cystatin-susceptible natural enemy by predation on susceptible and non-susceptible preys feeding on the plant. We have focussed on the impact of the variant HvCPI-1 C68 --> G, in which the only cysteine residue was changed by a glycine, on the growth and digestive physiology of the Colorado potato beetle (CPB), Leptinotarsa decemlineata, and the Egyptian cotton leafworm (ECW), Spodoptera littoralis. Moreover, we have studied the prey-mediated effects of the barley cystatin at the third trophic level, using the predatory spined soldier bug (SSB), Podisus maculiventris, as a model. Feeding trials conducted with CPB larvae reared on transgenic potato plants expressing the C68 --> G variant resulted in significantly lower weight gains compared to those fed on non-transformed (NT) plants. On the contrary, larger weight gains were obtained when ECW larvae, that lack digestive cysteine proteases, were reared on transgenic potato expressing the cystatin, as compared to larvae fed on NT plants. No negative effects on survival and growth were observed when SSB nymphs were exposed to HvCPI-1 C68 --> G by predation on either CPB or ECW larvae reared on transgenic potato plants expressing the barley cystatin, despite the fact that the inhibitor suppressed in vitro gut proteolysis of the predatory bug. To investigate the physiological background, biochemical analysis were carried out on guts of insects dissected at the end of the feeding assays.
authors.affiliation: Departamento de Biología de Plantas, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alvarez-Alfageme
authors.forename: Manuel
authors.initials: M
authors.lastname: Martínez
authors.forename: Sara
authors.initials: S
authors.lastname: Pascual-Ruiz
authors.forename: Pedro
authors.initials: P
authors.lastname: Castañera
authors.forename: Isabel
authors.initials: I
authors.lastname: Diaz
authors.forename: Félix
authors.initials: F
authors.lastname: Ortego
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001517:Coleoptera / Q000254:growth & development / Q000502:physiology; D015891:Cystatins / Q000235:genetics* / Q000494:pharmacology; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D020062:Heteroptera / Q000472:pathogenicity*; D001467:Hordeum / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011480:Protease Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000494:pharmacology; D011198:Solanum tuberosum / Q000235:genetics* / Q000469:parasitology*; D018411:Spodoptera / Q000254:growth & development / Q000502:physiology
chemical_list: D015891:Cystatins; D018744:DNA, Plant; D010940:Plant Proteins; D011480:Protease Inhibitors; D011994:Recombinant Proteins