Tailoring the composition of novel wax esters in the seeds of transgenic Camelina sativa through systematic metabolic engineering.
Tailoring the composition of novel wax esters in the seeds of transgenic Camelina sativa through systematic metabolic engineering.
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DOI：
10.1111/pbi.12679
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发表时间：
2017-07
影响因子：
13.8
通讯作者：
Beaudoin F
中科院分区：
文献类型：
--
作者：
Ruiz-Lopez N;Broughton R;Usher S;Salas JJ;Haslam RP;Napier JA;Beaudoin F
转基因植物中蜡生物合成酶的功能表征开启了在合适宿主作物的种子中生产定制蜡酯（WE）的可能性。在这项研究中，除了系统地评估一组WE生物合成活性外，我们还通过酰基-ACP硫酯酶的共表达来调节酰基-CoA底物库，以指导中链脂肪酸的积累。使用这种组合方法，我们确定了不同的酰基辅酶A池和生物合成酶底物特异性对转基因亚麻荠植物种子中非天然WE积累的附加贡献。总共制备了 14 个构建体，其中包含选定的 FAR 和 WS 基因以及酰基-ACP 硫酯酶。所有酶组合都成功生产了不同成分的蜡酯。酰基辅酶A硫酯酶表达对蜡酯积累的影响因WS的底物特异性而异。因此，酰基-ACP硫酯酶与Marinobacter Hydrooclasticus WS和Marinobacter aquaeolei FAR的共表达导致产生链长缩短的WE，而相同的酰基-ACP硫酯酶与Mus musculus WS和M. aquaeolei FAR的共表达对最终蜡的总体成分几乎没有影响。尽管酰基辅酶A库发生了实质性的重塑，这表明这些底物并未有效地整合到WE中。这些结果表明，底物库的修饰需要仔细选择 WS 和 FAR 活性，以便在亚麻荠种子中成功地大量积累这些新型蜡酯物种。
The functional characterization of wax biosynthetic enzymes in transgenic plants has opened the possibility of producing tailored wax esters (WEs) in the seeds of a suitable host crop. In this study, in addition to systematically evaluating a panel of WE biosynthetic activities, we have also modulated the acyl‐CoA substrate pool, through the co‐expression of acyl‐ACP thioesterases, to direct the accumulation of medium‐chain fatty acids. Using this combinatorial approach, we determined the additive contribution of both the varied acyl‐CoA pool and biosynthetic enzyme substrate specificity to the accumulation of non‐native WEs in the seeds of transgenic Camelina plants. A total of fourteen constructs were prepared containing selected FAR and WS genes in combination with an acyl‐ACP thioesterase. All enzyme combinations led to the successful production of wax esters, of differing compositions. The impact of acyl‐CoA thioesterase expression on wax ester accumulation varied depending on the substrate specificity of the WS. Hence, co‐expression of acyl‐ACP thioesterases with Marinobacter hydrocarbonoclasticus WS and Marinobacter aquaeolei FAR resulted in the production of WEs with reduced chain lengths, whereas the co‐expression of the same acyl‐ACP thioesterases in combination with Mus musculus WS and M. aquaeolei FAR had little impact on the overall final wax composition. This was despite substantial remodelling of the acyl‐CoA pool, suggesting that these substrates were not efficiently incorporated into WEs. These results indicate that modification of the substrate pool requires careful selection of the WS and FAR activities for the successful high accumulation of these novel wax ester species in Camelina seeds.