show Abstracthide AbstractVerticillium wilt which is caused by Verticillium dahliae causes massive annual losses of cotton yield. Control by conventional mechanisms is not possible due to wide host range and longevity of dormant fungi in the soil in case of absence of a suitable host. Plants have developed various mechanisms to boost their immunity against various diseases, and one of which is through the induction of various genes. In this research work, carried out of RNA sequencing and identified the members of the ABC genes are critical in enhancing resistance to V. dahliae infection. A total of 166 ABC genes were identified in Gossypium raimondii with varying physiochemical properties. A novel ABC gene, Gorai.007G244600 was found to be highly upregulated, its homolog in the tetraploid cotton Gh_D11G3432, was then silenced through virus induced gene silencing (VIGS) in tetraploid cotton, the mutant cotton seedlings that have the ability to tolerate V. dahliae infection were significantly reduced. Evaluation of oxidant, hydrogen peroxide (H2O2) and malondialdehyde (MDA) were found to have increased levels in the leaves of the mutant compared to the wild types. In addition, antioxidant enzymes, peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) concentration levels were significantly reduced in the mutant cotton compared to the wild types. Moreover, expression levels of the biotic stress genes, cotton polyamine oxidase (GhPAO), cotton ribosomal protein L18(GhRPL18) and cotton polygalacturonase-inhibiting protein-1 (GhPGIP1) were all downregulated in the mutant but highly upregulated in the wild cotton tissues. The outcome of this research has shown that ABC genes could be playing an important role in enhancing immunity of cotton to V. dahliae infection and can be explored in developing more resilient cotton genotypes with improved resistance to V. dahliae infection. Overall design: Examination of three tissues leaf, stem and root of three cotton species in three time points 0h, 12h and 48h with 81 samples which contain three biological duplication.