Isolation and Characterization of Twelve Polymorphic Microsatellite Loci for the Cocoa Mirid Bug Sahlbergella Singularis

Régis Babin,Ange-Marie Risterucci,Catherine Fenouillet,Marie-Pierre Chapuis,Laurence Blondin,Thierry Legavre,Caroline Calatayud

doi:10.3390/ijms13044412

Abstract

Mirids are the primary pests affecting cocoa production in Africa, but no genetic studies have been conducted on these insects. Here we report the isolation and characterization of 12 polymorphic microsatellite loci for Sahlbergella singularis. A microsatellite-enriched genomic DNA library was developed and screened to identify marker loci. Twelve polymorphic loci were identified by screening 28 individuals collected from one presumed population in cocoa plantations in Southern Cameroon. The number of alleles ranged from 5 to 25, whereas the observed and the expected heterozygosities ranged from 0.179 to 0.786 and from 0.671 to 0.946, respectively. Tests showed significant deviations from HW equilibrium for four loci, but no linkage disequilibrium was detected at any of the loci. No cross-species amplification was observed in two other mirid pests in Africa.

Highlights

The mirid Sahlbergella singularis Hagl. (Hemiptera: Miridae: Bryocorinae) is one of the primary pests affecting cocoa (Theobroma cacao L.) production in Africa, associated with 25 to 40%production losses
28 S. singularis individuals sampled from one presumed population for the study
Our results showed that a significant excess of homozygotes for loci Ss14 and Ss10 might be due to high prevalence of null alleles (i.e., ≥20%; Table 1)

Summary

Introduction

The mirid Sahlbergella singularis Hagl. (Hemiptera: Miridae: Bryocorinae) is one of the primary pests affecting cocoa (Theobroma cacao L.) production in Africa, associated with 25 to 40%. (Hemiptera: Miridae: Bryocorinae) is one of the primary pests affecting cocoa (Theobroma cacao L.) production in Africa, associated with 25 to 40%. Sahlbergella singularis is widely distributed in West Africa, present throughout the forest zone, from Sierra Leone to the Demographic Republic of Congo [1], and its life history is well known on cocoa [1,2]. Its natural host-plants are mainly forest trees of the Malvaceae [1] These trees are frequent neighbors or shade trees in cocoa agroforestry systems [3], their role in mirid population dynamics is unknown. (Hemiptera: Miridae), the second most important pest of cocoa in West Africa [1], and for a mirid bug of sorghum, Eurystylus oldi Poppius (Hemiptera: Miridae) We tested cross-species amplification for the closely related species Distantiella theobroma Distant. (Hemiptera: Miridae), the second most important pest of cocoa in West Africa [1], and for a mirid bug of sorghum, Eurystylus oldi Poppius (Hemiptera: Miridae)

Results and Discussion

F: Fam-GCTGGGTATTTGAGAGGGATT

Isolation of Microsatellite Markers

Primer Validation

Cross-Species Transferability

Conclusions