Biochemical Characterization of Orange-Colored Rice Calli Induced by Target Mutagenesis of OsOr Gene

• Published in: Plants (Basel) 2022-12, Vol.12 (1), p.56
• Main Authors: Kim, Hee Kyoung, Kim, Jin Young, Kim, Jong Hee, Go, Ji Yun, Jung, Yoo-Seob, Lee, Hyo Ju, Ahn, Mi-Jeong, Yu, Jihyeon, Bae, Sangsu, Kim, Ho Soo, Kwak, Sang-Soo, Kim, Me-Sun, Cho, Yong-Gu, Jung, Yu Jin, Kang, Kwon Kyoo
• Format: Article
• Language: English
• Subjects: Abiotic stress; Biosynthesis; Callus; Carotene; Carotenoids; CRISPR; CRISPR-Cas9; Editing; Flowers & plants; Fruits; Gene expression; Genes; Genomes; Isomers; Metabolic pathways; Mutagenesis; Mutation; orange gene (OsOr); orange-colored rice calli; Oxidation; Oxidative stress; Plastids; Rice; Salinity tolerance; Site-directed mutagenesis; β-Carotene
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants12010056

We generated an orange-colored (OC) rice callus line by targeted mutagenesis of the orange gene ( ) using the CRISPR-Cas9 system. The OC line accumulated more lutein, -carotene, and two -carotene isomers compared to the WT callus line. We also analyzed the expression levels of carotenoid biosynthesis genes by qRT-PCR. Among the genes encoding carotenoid metabolic pathway enzymes, the number of transcripts of the , , , and genes were higher in the OC line than in the WT line. In contrast, transcription of the gene was downregulated in the OC line compared to the WT line. In addition, we detected increases in the transcript levels of two genes involved in carotenoid oxidation in the OC lines. The developed OC lines also showed increased tolerance to salt stress. Collectively, these findings indicate that targeted mutagenesis of the gene via CRISPR/Cas9-mediated genome editing results in -carotene accumulation in rice calli. Accordingly, we believe that this type of genome-editing technology could represent an effective alternative approach for enhancing the -carotene content of plants.