Characterization of Cry toxins from autochthonous Bacillus thuringiensis isolates from Mexico

Molecular Characterization of the cry Gene profile of Bacillus thuringiensis Isolated from a Caribbean Region of Colombia

“…As mentioned above, the presence of cry1 and cry2 genes was not detected in any of the Bt-UPC samples that were toxic to mosquito larvae (Table SII). This result is concordant with results previously reported in Bt samples from Latin America, showing that cry1 and cry2 genes both together and separately are associated with toxicity against Lepidoptera and Coleoptera but not against larvae of Diptera (Uribe et al, 2003;Lopez-Pazos et al, 2009;Santos et al, 2012;Camacho-Millán et al, 2017;Pérez et al, 2016). It is noteworthy that the sequenced cry1 gene segments of the two Colombian B. thuringiensis samples were almost identical to the respective cry1A homolog of the subspecies named Bt kurstaki HD-1 isolated from a commercial insecticidal formulation called Dipel (Abbott Laboratories, North Chicago) (Kondo et al, 1987), differing from the database sequence only in two nucleotides which caused a non-silent mutation from serine to phenylalanine (Fig.…”

“…B. thuringiensis has been isolated from different ecosystems; the soil is one of the habitats in which it is most widely distributed (Arango et al, 2002;Jara et al, 2006;Pérez et al, 2016;Camacho-Millán et al, 2017;Soares-da-Silva et al, 2017). This fact, coupled with the wide variety of climatic regions and high diversity of insects in Colombia, provides opportunities to isolate new strains with toxic activity against Diptera or other insect orders (Ibarra et al, 2003).…”

“…Below each nucleotide sequence is the corresponding deduced amino acid segment. Millán et al, 2017), but in association with other cry genes toxic effects have also been reported against Dipteran larvae (Ben-Dov et al, 1997). In order to know whether cry1 and cry2 genes might be involved in toxic effects against Aedes aegypti larvae detected in Colombian Bt samples, the presence of these genes was investigated (Fig.…”

“…Studies of B. thuringiensis strains isolated from Latin America strongly suggest that there is a heterogeneous geographic distribution of cry genes associated with toxicity against different insect orders (Bravo et al, 1998;Ibarra et al, 2003;Uribe et al, 2003;López-Pazos et al, 2009;Santos et al, 2012;Pérez et al, 2016;Camacho-Millán et al, 2017;Soares-da-Silva et al, 2017). Colombian strains of B. thuringiensis have been isolated mainly from the central region, e.g.…”

“…In Central and South America, several infectious diseases which affect humans, animals and plants are transmitted by insect vectors from all orders (López-Pazos et al, 2009;Hernández-Fernández 2011;Pérez et al, 2016;WHO 2016;Camacho-Millán et al, 2017). Among them are Diptera such as mosquitoes of Ano pheles and Aedes genus involved in the transmission of malaria and dengue, respectively, which cause great impact in human heath (WHO 2016;Soares-da-Silva et al, 2017).…”