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Development of a genetic sexing strain in Bactrocera carambolae (Diptera: Tephritidae) by introgression of sex sorting components from B. dorsalis, Salaya1 strain.

Isasawin S, Aketarawong N, Lertsiri S, Thanaphum S - BMC Genet. (2014)

Bottom Line: This fruit fly belongs to Bactrocera dorsalis species complex.Further experiments showed that the sterile males of Salaya5 can compete with wild males for mating with wild females in field cage conditions.In addition, mating competitiveness tests suggested that Salaya5 has a potential to be used in B. carambolae SIT programs based on male-only releases.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: The carambola fruit fly, Bactrocera carambolae Drew & Hancock is a high profile key pest that is widely distributed in the southwestern ASEAN region. In addition, it has trans-continentally invaded Suriname, where it has been expanding east and southward since 1975. This fruit fly belongs to Bactrocera dorsalis species complex. The development and application of a genetic sexing strain (Salaya1) of B. dorsalis sensu stricto (s.s.) (Hendel) for the sterile insect technique (SIT) has improved the fruit fly control. However, matings between B. dorsalis s.s. and B. carambolae are incompatible, which hinder the application of the Salaya1 strain to control the carambola fruit fly. To solve this problem, we introduced genetic sexing components from the Salaya1 strain into the B. carambolae genome by interspecific hybridization.

Results: Morphological characteristics, mating competitiveness, male pheromone profiles, and genetic relationships revealed consistencies that helped to distinguish Salaya1 and B. carambolae strains. A Y-autosome translocation linking the dominant wild-type allele of white pupae gene and a free autosome carrying a recessive white pupae homologue from the Salaya1 strain were introgressed into the gene pool of B. carambolae. A panel of Y-pseudo-linked microsatellite loci of the Salaya1 strain served as markers for the introgression experiments. This resulted in a newly derived genetic sexing strain called Salaya5, with morphological characteristics corresponding to B. carambolae. The rectal gland pheromone profile of Salaya5 males also contained a distinctive component of B. carambolae. Microsatellite DNA analyses confirmed the close genetic relationships between the Salaya5 strain and wild B. carambolae populations. Further experiments showed that the sterile males of Salaya5 can compete with wild males for mating with wild females in field cage conditions.

Conclusions: Introgression of sex sorting components from the Salaya1 strain to a closely related B. carambolae strain generated a new genetic sexing strain, Salaya5. Morphology-based taxonomic characteristics, distinctive pheromone components, microsatellite DNA markers, genetic relationships, and mating competitiveness provided parental baseline data and validation tools for the new strain. The Salaya5 strain shows a close similarity with those features in the wild B. carambolae strain. In addition, mating competitiveness tests suggested that Salaya5 has a potential to be used in B. carambolae SIT programs based on male-only releases.

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Introgressive mating scheme for the construction of a genetic sexing of B. carambolae, Salaya5. Bcar, B. carambolae; Bdor, B. dorsalis; P, parents; F, filial generation and number; B2F, female line; and B2M, male line. wp+ and wp are wild type and mutant alleles, respectively. Awp+ and Awp refer to the free autosome carrying the wild type and mutant alleles, respectively. Y-Awp+ and A-Y denote the two reciprocal components of the Y-autosome translocation.
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Figure 4: Introgressive mating scheme for the construction of a genetic sexing of B. carambolae, Salaya5. Bcar, B. carambolae; Bdor, B. dorsalis; P, parents; F, filial generation and number; B2F, female line; and B2M, male line. wp+ and wp are wild type and mutant alleles, respectively. Awp+ and Awp refer to the free autosome carrying the wild type and mutant alleles, respectively. Y-Awp+ and A-Y denote the two reciprocal components of the Y-autosome translocation.

Mentions: The resulting F12 generation of the B2F line had descended from a repeated loop of the backcross-inbreeding-backcross scheme (i.e. F1 to F3, F4 to F6, F7 to F9, and F10 to F12; as suggested in the left column of Figure 4). The females (B2F) had, conceptually, a 99.6% genetic background of B. carambolae. Likewise, the F10 generation of the B2M line (B2M) had, conceptually, a 99.9% genetic background of B. carambolae. They were derived from the repeated backcross scheme as shown in the right column of Figure 4. All of the resulting offspring of B2F and B2M were true-breeding for white pupae and brown pupae characters, respectively. The white pupae phenotype in B2F offspring inferred that the white pupae marker (Awp/Awp) was completely introduced from the Salaya1 strain. However, the B2M line tentatively carrying the Y-Awp+ component still expresses all brown pupae characteristic in both sexes. This is because the Awp alleles had not yet been introduced during the introgression process. Therefore, the male progenies of the B2M line (with Y-Awp+/X; A-Y/Awp+ genotype) were crossed with the virgin females of B2F (with Awp/Awp genotype) to generate heterozygote Y-Awp+/X; A-Y/Awp progenies as shown in the middle column of Figure 4. These heterozygote progenies were then backcrossed with the B2F females to reproduce new true breeding brown-white pupae sexual dimorphisms (as shown in the bottom line of Figure 4). This new genetic sexing strain is called Salaya5.


Development of a genetic sexing strain in Bactrocera carambolae (Diptera: Tephritidae) by introgression of sex sorting components from B. dorsalis, Salaya1 strain.

Isasawin S, Aketarawong N, Lertsiri S, Thanaphum S - BMC Genet. (2014)

Introgressive mating scheme for the construction of a genetic sexing of B. carambolae, Salaya5. Bcar, B. carambolae; Bdor, B. dorsalis; P, parents; F, filial generation and number; B2F, female line; and B2M, male line. wp+ and wp are wild type and mutant alleles, respectively. Awp+ and Awp refer to the free autosome carrying the wild type and mutant alleles, respectively. Y-Awp+ and A-Y denote the two reciprocal components of the Y-autosome translocation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255791&req=5

Figure 4: Introgressive mating scheme for the construction of a genetic sexing of B. carambolae, Salaya5. Bcar, B. carambolae; Bdor, B. dorsalis; P, parents; F, filial generation and number; B2F, female line; and B2M, male line. wp+ and wp are wild type and mutant alleles, respectively. Awp+ and Awp refer to the free autosome carrying the wild type and mutant alleles, respectively. Y-Awp+ and A-Y denote the two reciprocal components of the Y-autosome translocation.
Mentions: The resulting F12 generation of the B2F line had descended from a repeated loop of the backcross-inbreeding-backcross scheme (i.e. F1 to F3, F4 to F6, F7 to F9, and F10 to F12; as suggested in the left column of Figure 4). The females (B2F) had, conceptually, a 99.6% genetic background of B. carambolae. Likewise, the F10 generation of the B2M line (B2M) had, conceptually, a 99.9% genetic background of B. carambolae. They were derived from the repeated backcross scheme as shown in the right column of Figure 4. All of the resulting offspring of B2F and B2M were true-breeding for white pupae and brown pupae characters, respectively. The white pupae phenotype in B2F offspring inferred that the white pupae marker (Awp/Awp) was completely introduced from the Salaya1 strain. However, the B2M line tentatively carrying the Y-Awp+ component still expresses all brown pupae characteristic in both sexes. This is because the Awp alleles had not yet been introduced during the introgression process. Therefore, the male progenies of the B2M line (with Y-Awp+/X; A-Y/Awp+ genotype) were crossed with the virgin females of B2F (with Awp/Awp genotype) to generate heterozygote Y-Awp+/X; A-Y/Awp progenies as shown in the middle column of Figure 4. These heterozygote progenies were then backcrossed with the B2F females to reproduce new true breeding brown-white pupae sexual dimorphisms (as shown in the bottom line of Figure 4). This new genetic sexing strain is called Salaya5.

Bottom Line: This fruit fly belongs to Bactrocera dorsalis species complex.Further experiments showed that the sterile males of Salaya5 can compete with wild males for mating with wild females in field cage conditions.In addition, mating competitiveness tests suggested that Salaya5 has a potential to be used in B. carambolae SIT programs based on male-only releases.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: The carambola fruit fly, Bactrocera carambolae Drew & Hancock is a high profile key pest that is widely distributed in the southwestern ASEAN region. In addition, it has trans-continentally invaded Suriname, where it has been expanding east and southward since 1975. This fruit fly belongs to Bactrocera dorsalis species complex. The development and application of a genetic sexing strain (Salaya1) of B. dorsalis sensu stricto (s.s.) (Hendel) for the sterile insect technique (SIT) has improved the fruit fly control. However, matings between B. dorsalis s.s. and B. carambolae are incompatible, which hinder the application of the Salaya1 strain to control the carambola fruit fly. To solve this problem, we introduced genetic sexing components from the Salaya1 strain into the B. carambolae genome by interspecific hybridization.

Results: Morphological characteristics, mating competitiveness, male pheromone profiles, and genetic relationships revealed consistencies that helped to distinguish Salaya1 and B. carambolae strains. A Y-autosome translocation linking the dominant wild-type allele of white pupae gene and a free autosome carrying a recessive white pupae homologue from the Salaya1 strain were introgressed into the gene pool of B. carambolae. A panel of Y-pseudo-linked microsatellite loci of the Salaya1 strain served as markers for the introgression experiments. This resulted in a newly derived genetic sexing strain called Salaya5, with morphological characteristics corresponding to B. carambolae. The rectal gland pheromone profile of Salaya5 males also contained a distinctive component of B. carambolae. Microsatellite DNA analyses confirmed the close genetic relationships between the Salaya5 strain and wild B. carambolae populations. Further experiments showed that the sterile males of Salaya5 can compete with wild males for mating with wild females in field cage conditions.

Conclusions: Introgression of sex sorting components from the Salaya1 strain to a closely related B. carambolae strain generated a new genetic sexing strain, Salaya5. Morphology-based taxonomic characteristics, distinctive pheromone components, microsatellite DNA markers, genetic relationships, and mating competitiveness provided parental baseline data and validation tools for the new strain. The Salaya5 strain shows a close similarity with those features in the wild B. carambolae strain. In addition, mating competitiveness tests suggested that Salaya5 has a potential to be used in B. carambolae SIT programs based on male-only releases.

Show MeSH
Related in: MedlinePlus