RETRACTED ARTICLE: Expression of a rice chitinase gene enhances antifungal response in transgenic litchi (cv. Bedana)

Abstract

To enhance the antifungal response of litchi (Litchi chinensis Sonn.), transgenic plants were generated by transferring rice chitinase gene driven by a maize-ubiquitin promoter along with its first intron into the zygotic embryos via Agrobacterium tumefaciens-mediated transformation. After co-cultivation for 2 days, zygotic embryos were transferred onto Murashige and Skoog (MS) modified media supplemented with 25 mgl−1 hygromycin and 400 mgl−1 cefotaxime. Consequently embryos were selected and the antibiotic resistant transgenic plantlets were regenerated. The culture time from zygotic embryo to transgenic plants was 14 months. The integration of the transgene was confirmed by PCR, RT-PCR, Southern and western blot analyses. The transgenic plants exhibited higher chitinase activity than the non-transformed plants. The chitinase activity when examined using the native polyacrylamide in-gel assay, indicated that the foreign gene expression resulting in the protein of expected molecular weight that showed chitinase activity. The transgenic plants showed delayed onset of the disease and smaller lesions following in vitro inoculation of die-back, leaf spots and blight pathogen (Phomopsis sp.). The transgenic plants were adapted to the greenhouse and did not show any phenotypic alterations.