Transcriptomic and Metabolomic Analyses of Orange Mutant in Tobacco

Purpose To analyze the transcriptome and metabolome of a tobacco Orange protein mutant, providing a theoretical foundation for cultivating tobacco with high carotenoid content.

Methods CRISPR/Cas9 technology was used to obtain a tobacco NtOR gene mutant (line 208) with a three-base deletion. The differential genes and metabolites of the mutant lines were analyzed by transcriptome sequencing, non-targeted liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS) derivatization and headspace injection techniques.

Results The contents of β-carotene and violaxanthin were significantly decreased in mutant line 208. Transcriptome analysis showed there were 10 369 differentially expressed genes in mutant line 208, with 4 178 up-regulated and 6 191 down-regulated genes. Metabolome analysis showed that mutant line 208 had 160 different metabolites compared with the control.

Conclusion In mutant line 208, the content of carotenoid decreases, and the zeaxanthin cyclooxygenase genes in pigment metabolism pathway are down-regulated, and the contents of organic acids and diterpenoids are significantly increased.