Secondary metabolite effects of different cocoa genotypes on feeding preference of the mirid Sahlbergella singularis Hagl

Mahob Raymond Joseph, Ngah I. Mama, Feumba R. Dibanda, Mahot H. C., Bassogog C. B. Bakwo, Bilong Charles Félix Bilong, Ebouel F. Edoun, Etam Pierre Boris Nsoga, Taliedje D.M., Hanna Rachid, Babin Régis. 2021. Secondary metabolite effects of different cocoa genotypes on feeding preference of the mirid Sahlbergella singularis Hagl. Arthropod-Plant Interactions, 15 (5) : 821-831.

https://doi.org/10.1007/s11829-021-09857-x

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Quartile : Q2, Sujet : ENTOMOLOGY

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : Sahlbergella singularis is a major insect pest of cocoa in Cameroon. Conventional insecticides remain the most widely used option for mirid control, which unfortunately have adverse effects on the environment and human health. Improved methods of controlling this species, both environmentally friendly and inexpensive to farmers, are requirements. Varietal control based on the selection of resistant and/or tolerant genotypes can be an interesting approach. Nonetheless, the role of secondary metabolites (SMs) in cocoa defense against mirids is poorly documented; yet, these compounds are reported to be key elements in plant defense against herbivores. For this purpose, SMs of twelve cocoa genotypes were identified and quantified, as well as their impact on food preference by mirids. Food preference was assessed through microtests measuring cocoa attractiveness and antixenosis toward mirids. The results showed that cocoa genotypes were differently accepted as food by mirids, with a significant preference for hybrid IMC60 x SNK605 and a non-preference for T60/887. The ten other cocoa genotypes showed intermediate results. Five SMs classes: alkaloids, flavonoids, polyphenols, saponins, and tannins were identified. Their rates varied between cocoa genotypes: polyphenols > alkaloids > flavonoids > tannins, and saponins. Cocoa genotypes with high total phenolic contents were significantly preferred by S. singularis (rα = 0.86, R2 = 74.0%, P < 0.001), while those with low saponins contents were lowly accepted (rα = − 0.83, R2 = 68.9%, P < 0.015), independently of the levels of other SMs. Given SMs high potential to affect mirid feeding behavior, analyzing cocoa SMs composition may help in early selection of resistant cocoa varieties against S. singularis.

Mots-clés Agrovoc : Theobroma cacao, Sahlbergella, résistance aux organismes nuisibles

Mots-clés complémentaires : Sahlbergella singularis

Mots-clés libres : Theobroma cacao, Biochemical analyses, Plant secondary metabolites, Attractiveness/antixenosis, Tolerant/resistant varieties, Insect-plant interactions

Classification Agris : H10 - Ravageurs des plantes
F60 - Physiologie et biochimie végétale

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

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