Transgenic rice plants expressing cry1Ia5 gene are resistant to stem borer (Chilo agamemnon)

The stem borer, Chilo agamemnon Bles., is the most serious insect pest in rice fields of the Egyptian Nile Delta. To induce rice plant resistance to Chilo agamemnon, the cry1Ia5 gene was introduced to rice plants (Oryza sativa L.). The integration of the cry1Ia5 gene into the plant genome was confirmed using PCR and Southern blot analyses. The obtained plantlets were transferred to the greenhouse until seeds were collected. Northern blot analysis of the T1 plants confirmed the expression of the cry1Ia5 gene. The insecticidal activity of the transgenic plants against the rice stem borer Chilo agamemnon were tested. The third larval instars were fed on stem cuts from three transgenic lines (L1, L2 and L3) as well as cuts from the control (gfp-transgenic) plants for one week and the mortality percentage was daily recorded. Transgenic line-3 showed the highest mortality percentage after one day (50%) followed by L2 (25%) then L1 (0%). Two days post treatment the mortality percentage increased to 70, 45 and 25% for transgenic lines 1, 2 and 3 respectively. Mortality of 100% was recorded four days post treatment, while those fed on the gfp-transgenic rice (control) showed 0% mortality. Thus, transgenic plants showed high resistance to stem borers and can serve as a novel genetic resource in breeding programs. Transgenic plants expressing BT protein were normal in phenotype with as good seed setting as the nontransgenic control plants.