Bioassay of Lepidopteran larvae resistance Cry gene in transgenic zea mays

Esmail Al Daham*(1)  and Fateh Khatib(1)

(1). Department of Plant Protection, Faculty of Agriculture, Aleppo University

(*corresponding author: Esmail Al Daham E-Mail: dhamasmayl2@gmail.com).

Received: 11/02/2022                      Accepted:23/03/2022

Abstract: 

Genetic engineering has been used to transfer genes from other organisms, in a way that cannot be achieved by conventional breeding, and has improved the performance of plants in the field, increasing their tolerance to certain biological and abiotic stresses. The Cry gene has been isolated from Bacillus thuringiensis subsp. Kurstaki HD1. It is toxic to nematode, insect pests, especially species of the order Lepidoptera, Coleoptera, and Diptera, which cause significant economic losses to major crops grown around the world. This study aimed to evaluate the toxic effect of Cry gene in some maize products spread in the local market of Aleppo city that have been shown to be transgenic through molecular tests using a Mediterranean flour butterfly as an alternative host. Plastic cans divided with plastic barriers, containing 100 g of corn flour per replicate , were used in the bioassay. The second instars were transferred to the boxes (replicates), twenty larva each and the sample was repeated for three times. The boxes were covered with a piece of muslin and fixed with a rubber band. The boxes were incubated at a temperature of 23 ± 2 °C, relative humidity 50 ± 5%, illumination (16 h light: 8 h dark), and the following readings were taken: larval longevity, larval weight, corrected kill percentage, length of pupal period, and the sexual fecundity for adults. The results of the statistical analysis showed that the longest period of time for the second larval life and the death of all larva 100% when fed on corn flakes and Argentine corn kernels. It also recorded a decrease in larvae weight and the number of eggs laid by insects whose larvae fed on corn grain and its genetically modified food products comparing to the control (non-transgenic flour).Deformations were observed on the whole insect, especially on the hind wings.

Key words: Bioassay, Cry gene, transgenic maize, Mediterranean flour butterfly.

Full paper in Arabic: pdf