Weselake Randall J, Shah Saleh, Tang Mingguo, Quant Patti A, Snyder Crystal L, Furukawa-Stoffer Tara L, Zhu Weiming, Taylor David C, Zou Jitao, Kumar Arvind, Hall Linda, Laroche Andre, Rakow Gerhard, Raney Phillip, Moloney Maurice M, Harwood John L
Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
J Exp Bot. 2008;59(13):3543-9. doi: 10.1093/jxb/ern206. Epub 2008 Aug 13.
Top-down control analysis (TDCA) is a useful tool for quantifying constraints on metabolic pathways that might be overcome by biotechnological approaches. Previous studies on lipid accumulation in oilseed rape have suggested that diacylglycerol acyltransferase (DGAT), which catalyses the final step in seed oil biosynthesis, might be an effective target for enhancing seed oil content. Here, increased seed oil content, increased DGAT activity, and reduced substrate:product ratio are demonstrated, as well as reduced flux control by complex lipid assembly, as determined by TDCA in Brassica napus (canola) lines which overexpress the gene encoding type-1 DGAT. Lines overexpressing DGAT1 also exhibited considerably enhanced seed oil content under drought conditions. These results support the use of TDCA in guiding the rational selection of molecular targets for oilseed modification. The most effective lines had a seed oil increase of 14%. Moreover, overexpression of DGAT1 under drought conditions reduced this environmental penalty on seed oil content.
自上而下的控制分析(TDCA)是一种用于量化代谢途径中可能通过生物技术方法克服的限制的有用工具。先前关于油菜籽脂质积累的研究表明,催化种子油生物合成最后一步的二酰甘油酰基转移酶(DGAT)可能是提高种子油含量的有效靶点。在此,通过TDCA在过表达编码1型DGAT基因的甘蓝型油菜(油菜)品系中测定,证明了种子油含量增加、DGAT活性增加、底物与产物比例降低,以及复合脂质组装的通量控制降低。过表达DGAT1的品系在干旱条件下也表现出种子油含量显著提高。这些结果支持使用TDCA来指导合理选择用于油籽改良的分子靶点。最有效的品系种子油增加了14%。此外,在干旱条件下过表达DGAT1减少了这种对种子油含量的环境惩罚。