Immune response and survival of Circulifer haematoceps to Spiroplasma citri infection requires expression of the gene hexamerin.
Spiroplasma citri is a cell wall-less bacterium that infects plants. It is transmitted by the leafhopper Circulifer haematoceps, which hosts this bacterium in the haemocel and insect tissues. Bacterial factors involved in spiroplasma colonization of the insect host have been identified, but the immune response of the leafhopper to S. citri infection remains unknown. In this study, we showed that C. haematoceps activates both humoral and cellular immune responses when challenged with bacteria. When infected by S. citri, C. haematoceps displayed a specific immune response, evidenced by activation of phagocytosis and upregulation of a gene encoding the protein hexamerin. S. citri infection also resulted in decreased phenoloxidase-like activity. Inhibition of hexamerin by RNA interference resulted in a significant reduction in phenoloxidase-like activity and increased mortality of infected leafhoppers. Therefore, the gene hexamerin is involved in S. citri control by interfering with insect phenoloxidase activity.
Institut National de la Recherche Agronomique (INRA), UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France; Université de Bordeaux, UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France.
Rémi
R
Eliautout
Institut National de la Recherche Agronomique (INRA), UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France; Université de Bordeaux, UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France.
Marie-Pierre
MP
Dubrana
Université de Lyon, INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, F-69621 Villeurbanne, France.
Carole
C
Vincent-Monégat
Université de Lyon, INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, F-69621 Villeurbanne, France.
Agnès
A
Vallier
Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie, Evolution, Symbiose.
Christine
C
Braquart-Varnier
INRA, Evolution and Specificity of Multitrophic Interactions (ESIM), UMR 1355 Institut Sophia Agrobiotech (ISA), Sophia Antipolis, France.
Marylène
M
Poirié
Institut National de la Recherche Agronomique (INRA), UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France; Université de Bordeaux, UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France.
Colette
C
Saillard
Université de Lyon, INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, F-69621 Villeurbanne, France.
Abdelaziz
A
Heddi
Institut National de la Recherche Agronomique (INRA), UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France; Université de Bordeaux, UMR 1332 Biologie du Fruit et Pathologie, Villenave d'Ornon, France. Electronic address: nbouvery@bordeaux.inra.fr.
Nathalie
N
Arricau-Bouvery
D000818:Animals; D055785:Gene Knockdown Techniques; D016905:Gram-Negative Bacterial Infections / Q000276:immunology*; D006430:Hemiptera / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D019476:Insect Proteins / Q000096:biosynthesis* / Q000276:immunology; D007303:Insect Vectors / Q000276:immunology* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D045642:Spiroplasma citri / Q000276:immunology
D019476:Insect Proteins; C041137:storage proteins, Insecta
Hemipteran innate immunity; Hexamerin; Immune cells; Phenoloxidase activity; RNAi; Spiroplasma