Bichang'a G., Da Lage J. L., Capdevielle Dulac Claire, Zivy M., Balliau T., Sambai K., Le Rü Bruno, Kaiser L., Juma G., Maina E. N. M., Calatayud Paul-André. (2018). Alpha-amylase mediates host acceptance in the Braconid parasitoid Cotesia flavipes. Journal of Chemical Ecology, 44 (11), p. 1030-1039. ISSN 0098-0331.
Titre du document
Alpha-amylase mediates host acceptance in the Braconid parasitoid Cotesia flavipes
Année de publication
2018
Auteurs
Bichang'a G., Da Lage J. L., Capdevielle Dulac Claire, Zivy M., Balliau T., Sambai K., Le Rü Bruno, Kaiser L., Juma G., Maina E. N. M., Calatayud Paul-André
Source
Journal of Chemical Ecology, 2018,
44 (11), p. 1030-1039 ISSN 0098-0331
Foraging parasitoids use chemical signals in host recognition and selection processes. Although, the volatiles play a relevant role in the localization by parasitoids of their hosts feeding on plants, the host identification process for acceptance occurs mainly during contact between the parasitoid and its host where host products related to feeding activities, fecal pellets and oral secretions, play a crucial role. The purpose of this study was to identify the nature of the contact kairomone(s) that mediate the acceptance for oviposition of the parasitoid Cotesia flavipes Cameron (Hymenoptera, Braconidae), which was released in Kenya in 1993 to control the invasive crambid Chilo partellus (Swinhoe). Using host and non-hosts of C. flavipes, we showed that it is mainly the oral secretions of the larvae that harbour the active compound(s) that mediate host acceptance for oviposition by C. flavipes. Using an integration of behavioral observations and biochemical approaches, the active compound of the oral secretions was identified as an alpha-amylase. Using synthetized alpha-amylases from Drosophila melanogaster (an insect model for which syntheses of active and inactive alpha-amylases are available), we observed that the conformation of the enzyme rather than its catalytic site as well as its substrate and its degradation product is responsible for host acceptance and oviposition mediation of C. flavipes females. The results suggest that the alpha-amylase from oral secretions of the caterpillar host is a good candidate for an evolutionary solution to host acceptance for oviposition in C. flavipes.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Sciences du monde végétal [076]
Localisation
Fonds IRD [F B010074107]
Identifiant IRD
fdi:010074107
