Assessment of Cry1Ac and Cry2A expression endotoxins in transgenic cotton across growth periods and stages under semi-controlled conditions

Abstract

Mahreen Hanif, Shafqat Saeed*, Zuluqrnain Khan, Mudssar Ali, Muhammad Ishtiaq

Transgenic cotton has brought about a significant transformation in the management of bollworms. Nevertheless, a considerable challenge has emerged in the form of Pectinophora gossypiellafor transgenic cotton. In current study, the detection and quantification of Cry1Ac and Cry2Ab protein in pot samples of different transgenic cotton cultivars encompassing single (Cry1Ac) and double gene (Cry2Ab) cultivars was conducted, employing bt strips and ELISA methods at three distinct time points, namely 40 days, 80 days, and 120 days after sowing, coinciding with different growth phases (i.e., leaves, squares, bolls, and seeds). The outcomes revealed that the highest toxin levels of Cry1Ac protein were present across all cultivars, whereas elevated levels of Cry2Ab protein were exclusively observed in MNH-1045 cultivar ranged from 0.05 ug/g to 1.46 ug/g. The findings highlighted visible differences in the concentrations of Cry1Ac and Cry2Ab proteins among all cultivars. The Cry1Ac concentrations ranged from 0.12 ug/g to 0.81 ug/g, 0.18 ug/g to 0.69 ug/g, 0.19 ug/g to 0.38 ug/g after 40 days, 80 days, and 120 days respectively, and ranged from 0.22 ug/g to 0.59 ug/g, 0.20 ug/g to 0.36 ug/g, 0.00 ug/g to 0.05 ug/g and 0.22 ug/g to 0.30 ug/g, in leaf, square, boll, and seed stage respectively. The concentration of Cry2Ab protein ranged from 0.04 to 1.46, 0.02 to 1.128, 0.01 to 0.28ug/g after 40 days, 80 days, and 120 days respectively, and ranged from 0.4 ug/g to 1.45 ug/g, 0.01 ug/g to 0.63 ug/g, 0.00 ug/g to 0.05 ug/g and 0.00 ug/g to 0.62 ug/g, in leaf, square, boll, and seed stage respectively. It was detected that the expression of toxins is depending upon the developmental stage of the crop and the duration of growth. This study's findings will aid entomologists and plant breeders in developing high-toxin cotton cultivars (especially expressing high at the boll stage) and strategies for global cotton production sustainability, such as refuge maintenance or hybrid development, to protect transgenic cotton from pink bollworm infestations.