of the Bt isolates toxicity spectrum (Juárez-Pérez et al. 1997; Ferrandis et al. 1999).
To date, different cry, cyt, sip, vip and ps genes were screened in the Iranian Bt
collections. Correspondingly, the toxicity spectrum of Bt strains has been predicted
based on the different δ-endotoxin genes. The presence of different lepidopteran-,
coleopteran-, and dipteran-active genes, as well as Bt genes active against nematodes, was investigated in an Iranian Bt collection (Salehi Jouzani et al. 2008b, c;
Seifinejad et al. 2008; Nazarian et al. 2009). Iranian Bt strains were characterized
based on their gene content and the presence of lepidopteran-active genes, namely
cry1Aa, cry1Ab, cry1Ac, cry1Ad, cry1B, cry1C, cry1D, cry1E, cry1F, cry1G, cry1H,
cry1I, cry1J, cry1K, cry2Aa, cry2Ab, cry2Ac, cry9A, cry9B, cry9C, cry9D and
vip3Aa (Seifinejad et al. 2008). Based on the PCR analysis, the Bt strains harboring
lepidopteran-active genes were selected for the bioassays (Seifinejad et al. 2008).
The presence of cry1B, cry1I, cry3A, cry3B, cry3C, cry7A, cry8A, cry8B, cry8C,
cry14, cry18, cry26, cry28, cry34 and cry35 genes, coleopteran specific cry genes
were determined (Nazarian et al. 2009). Afterward, the Bt strains containing coleopteran active cry genes were bioassayed against the elm leaf beetle,
Xanthogaleruca luteola Muller (Col.: Chrysomellidae), first instar larvae (Nazarian
et al. 2009). The number of 22 dipteran-active cry and cyt genes, including; cry2Aa1,
cry1Ab2, cry2Ac, cry4Aa, cry4B, cry10, cry11Aa, cry11Ba, cry11Bb, cry17Aa1,
cry19Aa1, cry19Ba1, cry21Aa1, cry21Aa2, cry21Ba1, cry24Ba1, cry29, cry30,
cry32Aa, cry32Ba, cry32Ca, cry32D, cry39, cry49Aa, cyt1Aa, cyt1Ab1, cyt1Ba,
cyt2Aa, cyt2Ba, cyt2Bb and cyt2Ca, were traced in the 128 Iranian local Bt strains
(Salehi Jouzani et al. 2008b). The cry2 gene family was the most frequent in this Bt
collection. According to the PCR analysis and the gene content of the studied Bt
strains, high potent Bt strains active against mosquitoes can be introduced from this
collection. Besides the Bt genes targeting insects, the presence of cry genes active
against parasitic or free-living nematodes, has been assessed (Salehi Jouzani et al.
2008c). The Bt strains were screened for the presence of cry5, cry6, cry12, cry13,
cry14 and cry21 as the nematode-active genes. The presence of the nematode-active
genes were found and these strains were bioassayed against nematodes. Although,
there is a correlation between the gene profile and the geographical origin of Bt
strains, the most frequent and common Bt genes found in different Bt screenings all
over the country are, cry2, cry1 and vip3Aa genes families.
10.8.4 Protein Profile
The PCR-based technique rapidly determines the presence or absence of genes,
while it does not necessarily identify the expression of the identified gene. Therefore,
protein electrophoresis of Bt crystal proteins is helpful for characterization and also
for comparison of the protein profile. Based on the molecular masses of the observed
band in SDS-PAGE analysis, the insecticidal activity of Bt strains is predicted. The
protein profile of Bt isolates with dipteran-active cry and cyt genes was assessed by
Salehi Jouzani et al. (2008b). Regardless of the origin of Bt strains, diverse protein
412
A. Khorramnejad et al.
To date, different cry, cyt, sip, vip and ps genes were screened in the Iranian Bt
collections. Correspondingly, the toxicity spectrum of Bt strains has been predicted
based on the different δ-endotoxin genes. The presence of different lepidopteran-,
coleopteran-, and dipteran-active genes, as well as Bt genes active against nematodes, was investigated in an Iranian Bt collection (Salehi Jouzani et al. 2008b, c;
Seifinejad et al. 2008; Nazarian et al. 2009). Iranian Bt strains were characterized
based on their gene content and the presence of lepidopteran-active genes, namely
cry1Aa, cry1Ab, cry1Ac, cry1Ad, cry1B, cry1C, cry1D, cry1E, cry1F, cry1G, cry1H,
cry1I, cry1J, cry1K, cry2Aa, cry2Ab, cry2Ac, cry9A, cry9B, cry9C, cry9D and
vip3Aa (Seifinejad et al. 2008). Based on the PCR analysis, the Bt strains harboring
lepidopteran-active genes were selected for the bioassays (Seifinejad et al. 2008).
The presence of cry1B, cry1I, cry3A, cry3B, cry3C, cry7A, cry8A, cry8B, cry8C,
cry14, cry18, cry26, cry28, cry34 and cry35 genes, coleopteran specific cry genes
were determined (Nazarian et al. 2009). Afterward, the Bt strains containing coleopteran active cry genes were bioassayed against the elm leaf beetle,
Xanthogaleruca luteola Muller (Col.: Chrysomellidae), first instar larvae (Nazarian
et al. 2009). The number of 22 dipteran-active cry and cyt genes, including; cry2Aa1,
cry1Ab2, cry2Ac, cry4Aa, cry4B, cry10, cry11Aa, cry11Ba, cry11Bb, cry17Aa1,
cry19Aa1, cry19Ba1, cry21Aa1, cry21Aa2, cry21Ba1, cry24Ba1, cry29, cry30,
cry32Aa, cry32Ba, cry32Ca, cry32D, cry39, cry49Aa, cyt1Aa, cyt1Ab1, cyt1Ba,
cyt2Aa, cyt2Ba, cyt2Bb and cyt2Ca, were traced in the 128 Iranian local Bt strains
(Salehi Jouzani et al. 2008b). The cry2 gene family was the most frequent in this Bt
collection. According to the PCR analysis and the gene content of the studied Bt
strains, high potent Bt strains active against mosquitoes can be introduced from this
collection. Besides the Bt genes targeting insects, the presence of cry genes active
against parasitic or free-living nematodes, has been assessed (Salehi Jouzani et al.
2008c). The Bt strains were screened for the presence of cry5, cry6, cry12, cry13,
cry14 and cry21 as the nematode-active genes. The presence of the nematode-active
genes were found and these strains were bioassayed against nematodes. Although,
there is a correlation between the gene profile and the geographical origin of Bt
strains, the most frequent and common Bt genes found in different Bt screenings all
over the country are, cry2, cry1 and vip3Aa genes families.
10.8.4 Protein Profile
The PCR-based technique rapidly determines the presence or absence of genes,
while it does not necessarily identify the expression of the identified gene. Therefore,
protein electrophoresis of Bt crystal proteins is helpful for characterization and also
for comparison of the protein profile. Based on the molecular masses of the observed
band in SDS-PAGE analysis, the insecticidal activity of Bt strains is predicted. The
protein profile of Bt isolates with dipteran-active cry and cyt genes was assessed by
Salehi Jouzani et al. (2008b). Regardless of the origin of Bt strains, diverse protein
412
A. Khorramnejad et al.