A gene stacking approach leads to engineered plants with highly increased galactan levels in Arabidopsis.
A gene stacking approach leads to engineered plants with highly increased galactan levels in Arabidopsis.
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DOI：
10.1186/s12870-014-0344-x
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发表时间：
2014-12-10
影响因子：
5.3
通讯作者：
Scheller HV
中科院分区：
文献类型：
--
作者：
Gondolf VM;Stoppel R;Ebert B;Rautengarten C;Liwanag AJ;Loqué D;Scheller HV
对含有更适合于下游加工的木质纤维生物质成分的植物进行工程设计，对下一代生物燃料的生产具有很高的兴趣。木质纤维生物质含有较高比例的戊糖残基，比己糖更难转化为燃料。因此，提高生物质中己糖/戊糖的比例是提高生物质产量的途径之一。用基因工程的方法研究了在拟南芥纤维细胞的细胞壁中果胶半乳糖的含量是否可以特异性地增加，这反过来又可以提供一个容易发酵的半乳糖的潜在来源。首先，研究了多种植物UDP-葡萄糖4-差向异构酶(UGE)的过表达是否能提高UDP-半乳糖的利用率，从而促进半乳糖的生物合成。一个杨树UGE和三个拟南芥uGE的结构性和组织特异性表达不能显著增加细胞壁结合的半乳糖的量。然后，我们研究了AtUGE 2和β-1，4-半乳聚糖合成酶GalS1的共过表达。AtUGE2和GalS1的共过表达导致拟南芥茎细胞壁半乳糖水平增加80%以上，这为这些蛋白质协同工作提供了证据。此外，AtUGE2和GalS1的过表达以及NST1次生细胞壁生物合成主调控子的过表达除了导致高水平的半乳糖水平外，还导致纤维细胞壁厚度的增加。免疫荧光显微镜证实，增加的半乳糖以β-1，4-半乳糖形式存在于次生细胞壁。这一方法清楚地表明，同时过表达AtUGE2和GalS1会将细胞壁的半乳糖增加到比单独过度表达这两种蛋白中的任何一种都高得多的水平。此外，纤维细胞中半乳糖含量的增加虽然改善了生物量组成，但对植物的生长发育没有影响，因此对总生物量没有影响。因此，我们可以证明，这里描述的基因堆积方法是一种很有前途的方法，可以为生物燃料生产设计先进的原料。
Engineering of plants with a composition of lignocellulosic biomass that is more suitable for downstream processing is of high interest for next-generation biofuel production. Lignocellulosic biomass contains a high proportion of pentose residues, which are more difficult to convert into fuels than hexoses. Therefore, increasing the hexose/pentose ratio in biomass is one approach for biomass improvement. A genetic engineering approach was used to investigate whether the amount of pectic galactan can be specifically increased in cell walls of Arabidopsis fiber cells, which in turn could provide a potential source of readily fermentable galactose. First it was tested if overexpression of various plant UDP-glucose 4-epimerases (UGEs) could increase the availability of UDP-galactose and thereby increase the biosynthesis of galactan. Constitutive and tissue-specific expression of a poplar UGE and three Arabidopsis UGEs in Arabidopsis plants could not significantly increase the amount of cell wall bound galactose. We then investigated co-overexpression of AtUGE2 together with the β-1,4-galactan synthase GalS1. Co-overexpression of AtUGE2 and GalS1 led to over 80% increase in cell wall galactose levels in Arabidopsis stems, providing evidence that these proteins work synergistically. Furthermore, AtUGE2 and GalS1 overexpression in combination with overexpression of the NST1 master regulator for secondary cell wall biosynthesis resulted in increased thickness of fiber cell walls in addition to the high cell wall galactose levels. Immunofluorescence microscopy confirmed that the increased galactose was present as β-1,4-galactan in secondary cell walls. This approach clearly indicates that simultaneous overexpression of AtUGE2 and GalS1 increases the cell wall galactose to much higher levels than can be achieved by overexpressing either one of these proteins alone. Moreover, the increased galactan content in fiber cells while improving the biomass composition had no impact on plant growth and development and hence on the overall biomass amount. Thus, we could show that the gene stacking approach described here is a promising method to engineer advanced feedstocks for biofuel production.
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影响因子：
11.6
作者：
Rosti, Johannes;Barton, Christopher J.;Seifert, Georg J.
通讯作者：
Seifert, Georg J.
影响因子：
13.8
作者：
Yang F;Mitra P;Zhang L;Prak L;Verhertbruggen Y;Kim JS;Sun L;Zheng K;Tang K;Auer M;Scheller HV;Loqué D
通讯作者：
Loqué D
DOI：
10.1073/pnas.1406073111
发表时间：
2014-08-05
影响因子：
11.1
作者：
Rautengarten, Carsten;Ebert, Berit;Orellana, Ariel
通讯作者：
Orellana, Ariel
影响因子：
7.4
作者：
Nguema-Ona, E;Andème-Onzighi, C;Driouich, A
通讯作者：
Driouich, A
影响因子：
7.2
作者：
Clough, SJ;Bent, AF
通讯作者：
Bent, AF