Integration of transcriptome analysis with CRISPR/Cas9 technology provides new opportunities for uncovering transcriptional regulation of hyperaccumulation in Sedum plumbizincicola

Abstract

Cadmium-hyperaccumulator Sedum plumbizincicola possesses strong capacities of Cd transport, accumulation and detoxification, but the transcriptional regulation mechanisms of Cd hyperaccumulation remain unknown. In this study, we examined the comparative transcriptome between S. plumbizincicola and non-accumulator Sedum alfredii with or without Cd treatments. Many differentially expressed genes involved in heavy metal transport and detoxification were found to be abundantly expressed in S. plumbizincicola. Meanwhile, a large number of differentially expressed transcription factor genes had been identified and revealed the complexity of transcriptional regulatory networks. Four transcription factor genes that were highly expressed in the roots of S. plumbizincicola were screened as candidate genes for creating CRISPR/Cas9 knockout mutations. The mutant lines of SpARR11 and SpMYB84 exhibited decreased Cd accumulation in the aboveground parts, indicating that the two transcription factors may be involved in the regulation of the Cd hyperaccumulation in S. plumbizincicola. Although further research will be needed to determine the precise targeted genes of these transcription factors, this study combining transcriptome analysis and CRISPR/Cas9 genome editing technology offers unprecedented opportunities to mine transcription factors related to Cd hyperaccumulation and contributes to uncovering the transcriptional regulation mechanism of hyperaccumulation in S. plumbizincicola.