Transformation of Maize Elite Lines with cry1Ca of Bacillus thuringiensis to Control Spodoptera frugiperda

Fall armyworm, Spodoptera frugiperda, is the most important insect pest of corn in Brazil. Bacillus thuringiensis (Bt) is an insect pathogen that may be used to control this insect in the field. Strain 1644, discovered in a soil sample in the south of Brazil, was found to be very efficient in controlling this insect in laboratory bioassays. This strain harbors the cry1C gene (2.7 Kb). Twelve primers were used to perform the sequencing along the gene. After sequencing, cry1C gene was cloned in the pCAMBIA 3301 vector, under the control of the ubiquitin promoter and terminator NOS. The plasmid was amplified in Escherichia coli strain DH5α, purified in CsCl gradient and used to transform tropical maize (Zea mays L.) calli via biobalistic process. The integration of cry1C gene was confirmed by PCR in 13 maize plants generated. Leaves of transgenic plants regenerated directly from callus lines were bioassayed with S. frugiperda and showed different levels of resistance to this insect pest, and one inbred line, L3, inhibited 100 % of larval growth (L3 – Elite line transgenic corn belongs to Embrapa Maize and Sorghum Research Center)