Down-regulation of β-carotene hydroxylase increases β-carotene and total carotenoids enhancing salt stress tolerance in transgenic cultured cells of sweetpotato

► Sweetpotato IbCHY-β RNAi transgenic calli increased β-carotene and total carotenoids. ► Transgenic cell lines also showed enhanced antioxidant capacity under salt stress. ► Interestingly, the transgenic calli accumulated more ABA content. ► It is suggested that enhanced levels of carotenoids contribute to stress tolerance in transgenic plants.