Down-regulation of I bCHY increases p-carotene contents and enhances salt stress resistance in transgenic sweetpotato cultured cells
Sweetpotato (Ipomoea batatas L.) is an important food and industrial crop to produce useful components including various antioxidants such as carotenoids. To increase P-carotene contents in svveetpotato,inhibition of further hydrolysis of Pcarotene by CHY silencing strategy in carotenoid biosynthetic pathway was considered. Thus, we have cloned a partial cDNA encoding CHY-β from the storage roots of yellow-fleshed sweetpotato (cv. Shinhwangmi) and generated RNAi-IbCHY-β construct. This construct was introduced into cultured cells of white-fleshed sweetpotato (cv. Yulmi) by Agrobac-terium-mediated transformation. RT-PCR analysis confirmed successful suppression of IbCHY-β gene expression in transgenic sweetpotato cultured cells. Gene expression of other enzymes in carotenoid biosynthesis was also investigated in transgenic callus cells. The expression level of lycopene P-cyclase showed clear increase while the expressions of other genes showed no detectable changes. Down-regulation of IbCHY-β gene expression has changed carotenoids composition and flux between wild type and transgenic cells. Total carotenoids contents of transgenic lines reached to maximum 117 Mg/g dry weight (line 7) and the major carotenoid has been changed from violaxanthin to P-carotene. DPPH radical scavenging activity in transgenic cells remarkably increased up to 4 times. Production of reactive oxygen species measured by DAB staining also decreased in transgenic cultured cells under salt stress condition. These results Indicate that increased carotenoids levels contribute to have enhanced tolerance to salt stress by scavenging reactive oxygen species.
sweetpotato carotenoid P-carotene P-carotene hydroxylases RNA interference metabolic engineering
KIM Sun Ha AHN Young Ock LEE Haeng-Soon KWAK Sang-Soo
Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB),Daejeon 305-806,Korea
国际会议
徐州
英文
173-181
2010-11-27（万方平台首次上网日期，不代表论文的发表时间）