Cross-species amplification and polymorphism of microsatellite loci in Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) in Brazilian cropping systems

Abstract

ABSTRACT. The Old World bollworm Helicoverpa armigera (Hübner) was recently discovered in Brazil. This species is closely related to the New World bollworm H. zea (Boddie), and mating between these species has already been reported under laboratory conditions. Here, we tested the cross-species amplification of 20 microsatellite (SSR) loci in field populations of H. armigera and H. zea collected from Brazilian cropping systems. Seven SSR loci were successfully amplified and polymorphic in both species except for the locus HaC14, which was monomorphic for H. zea. All SSR loci were in linkage equilibrium, and deviations from HardyWeinberg equilibrium were only observed for the locus HarSSR1 in the HaRS-2 population, where null alleles were present. A moderate level of polymorphism was detected in H. armigera and H. zea populations with a mean allele number of 4.14, and 2.24, respectively. Interestingly, most of the populations of the recent invader H. armigera showed higher genetic diversity and inbreeding coefficients than H. zea populations. The genetic identity of each species was recovered using a STRUCTURE analysis, where the populations formed two clusters (K = 2) according to their species. STRUCTURE also suggested the occurrence of potential hybrid offspring between H. armigera and H. zea individuals in natural conditions. These SSR loci will be valuable in characterizing population differentiation, invasion routes, adaptation, reproductive behavior, and intra-and interspecific gene flow in H. armigera and H. zea populations in Brazil, the USA, and other areas where these two pests occur.

Mitochondrial DNA genomes of five majorHelicoverpapest species from the Old and New Worlds (Lepidoptera: Noctuidae)

“…Microsatellite DNA markers in the Lepidoptera including Helicoverpa species are often affected by transposable elements (Gordon, Tay, Collinge, Williams, & Batterham, ; Tay, Behere, Batterham, & Heckel, ), and alternative nuclear DNA markers should be used instead where possible (i.e., EPIC‐PCR markers, see Behere, Tay, Russell, Kranthi, and Batterham () and Tay, Behere, Heckel, Lee, and Batterham (). Nevertheless, signatures of interspecific H. armigera ‐ H. zea hybridization as inferred from microsatellite loci have been reported by Leite et al (). Future monitoring of Helicoverpa species at preborder inspection could also consider the method of Nagoshi, Gilligan, and Brambila () that incorporates the z‐linked Triosephosphate isomerase (Tpi) gene with the mtCOI gene for identifying potential H. armigera ‐ H. zea hybrids, although the feasibility of transferring this method to screen for potential H. armigera ‐ H. gelotopoeon , H. assulta ‐ H. gelotopoeon , H. assulta ‐ H. zea , and H. armigera ‐ H. assulta hybrids remained to be tested.…”

“…The restriction enzymes selected represented a more comprehensive in silico analysis of publicly available partial COI sequences and avoided the need to include the partial Cyt b gene RFLP analysis originally designed by Behere et al (). The revised RFLP method has not included the restriction enzymes identified by both Arneodo et al () and Behere et al () because of novel mtCOI haplotypes identified from global populations of H. armigera including from South America (e.g., Arnemann, ; Arnemann et al, ; Leite et al, ; Tay, Walsh et al, ).…”

“…Sequences were identified for restriction enzyme(s) and predicted RFLP patterns using the CLC Sequence Viewer 7 program. Relevant partial COI and Cyt b gene regions previously reported (Arnemann et al, 2016;Arneodo et al, 2015;Behere et al, 2008;Leite et al, 2016;Tay, Walsh et al, 2017) were also included in the current study (Supporting Information Data S2 and S3-GenBank accession numbers and sequences used for RFLP).…”

“…gene RFLP analysis originally designed by Behere et al (2008). The revised RFLP method has not included the restriction enzymes identified by both Arneodo et al (2015) and Behere et al (2008) because of novel mtCOI haplotypes identified from global populations of H. armigera including from South America (e.g., Arnemann, 2015;Arnemann et al, 2016;Leite et al, 2016;Tay, Walsh et al, 2017).…”

Resistance to pyrethroid and oxadiazine insecticides in <i>Helicoverpa armigera</i> (Lepidoptera: Noctuidae) populations in Brazil

“…The high frequency of the chimeric P450 enzyme CYP337B3 gene in H. armigera populations indicates that pyrethroid insecticides should not be recommended in Brazil or in the rest of the Americas, due to the high dispersal capacity and gene flow among H. armigera populations (Feng et al, 2005;Jones et al, 2015;Leite et al, 2016).…”