Development of whitefly-resistant cotton by transforming the Tma12 gene isolated from Tectaria macrodonta

Abstract

Farah Naz*, Arfan Ali, Ghulam Zahara Jahangir, Usman Arif, Qurban Ali, Muhammad Tariq, Abdul Munim Farooq and Idrees Ahmad Nasir

Cotton is white gold and contributes significantly to the economy of the countries. The process of evolution of resistance in various cotton insects directly affects the life of people. Among the cotton insect pests, the sucking pests have turned out to be destructive. The sap sucking insects especially whitefly (Bemisia tabaci) has emerged as major agricultural pests. So, the efforts are now being engaged in improving Genetically Modified (GM) cotton varieties resistant to whitefly. None of the insecticidal proteins used in Genetically Modified (GM) crop plants to date are effective against whitefly. Some insecticidal proteins showed significant toxicity against the whiteflies such as Hvt, lectin, and Tma12 proteins. The identified Tma12 protein from an edible fern, Tectaria macrodonta that is insecticidal to whitefly and interferes with its life cycle. But still the understanding of the biological function of fern genes and their potential uses for agriculture, environment and health has been hampered by the lack of high-quality genome sequence of fern. In this study, gene cassette comprising CAMV35S promoter, Tma12 gene isolated from Tectaria macrodonta and NOS terminator respectively was synthesized and cloned in the plant expression vector. This respective gene cassette was transformed via agrobacterium-mediated transformation. The putative transgenic plants were screened through conventional PCR. Moreover, the mRNA expression of the Tma12 gene was in five plants which was 3-fold higher in transgenic cotton line as compared to the non-transgenic cotton plants. Finally, the insect bioassay with five transgenic cotton lines showed up to 70% mortality against whitefly. Study is important as it will enhance resistance of local triple gene cotton variety against whitefly. This novel insecticidal protein fulfils the need to combat resistance build-up against sucking pests especially whitefly.