Enhanced saccharification of rice straw by overexpression of rice exo-glucanase.
Enhanced saccharification of rice straw by overexpression of rice exo-glucanase.
复制标题
DOI：
10.1186/1939-8433-5-14
复制
发表时间：
2012-06-28
期刊：
影响因子：
--
通讯作者：
Ito Y
中科院分区：
文献类型：
--
作者：
Nigorikawa M;Watanabe A;Furukawa K;Sonoki T;Ito Y
高效生产碳中性生物燃料是解决全球变暖和化石燃料枯竭问题的关键。纤维素是最丰富的生物质，其物理强度和生物化学稳定，并且这些特征导致难以有效糖化纤维素化合物以生产可发酵的葡萄糖和其它糖。我们用编码三类纤维素酶的水稻基因的过表达构建体转化水稻。外源葡聚糖酶过量表达的植株表现出叶片分裂、叶片表面裂纹、中脉结构空隙过多和坏死变色等多种异常现象。过表达的植株也表现出不育性。值得注意的是，这些植物在成熟后茎的糖化作用增强。这些结果表明，外切葡聚糖酶基因的过量表达导致了水稻细胞壁修饰和糖化作用增强等多种发育缺陷。另一方面，不能获得过量表达内切葡聚糖酶的植物，并且过量表达β-葡萄糖苷酶对植物生长发育没有影响。我们的研究结果表明，通过过表达纤维素酶基因的纤维素生物质植物的基因工程将是赋予纤维素生物燃料，如乙醇的有效生产增强的糖化能力的方法之一。本文的在线版本（doi：10.1186/1939-8433-5-14）包含补充材料，可供授权用户使用。
Efficient production of carbon-neutral biofuels is key to resolving global warming and exhaustion of fossil fuels. Cellulose, which is the most abundant biomass, is physically strong and biochemically stable, and these characteristics lead to difficulty of efficient saccharification of cellulosic compounds for production of fermentable glucose and other sugars. We transformed rice with overexpressing constructs of rice genes encoding each of three classes of cellulases. The exo-glucanase overexpressing plants showed various abnormalities in leaf such as division of leaf blade, crack on leaf surface, excess lacunae in midrib structure and necrotic colour change. The overexpressing plants also showed sterility. Noticeably, these plants showed enhanced saccharification of stems after maturation. These results indicate that overexpression of the exo-glucanase gene brought about various developmental defects associated with modification of cell wall and enhanced saccharification in rice. On the other hand, endo-glucanase-overexpressing plants could not be obtained, and overexpression of β-glucosidase brought about no effect on plant growth and development. Our results indicate that genetic engineering of cellulosic biomass plants by overexpressing cellulase genes will be one of the approaches to confer enhanced saccharification ability for efficient production of cellulosic biofuels such as ethanol. The online version of this article (doi:10.1186/1939-8433-5-14) contains supplementary material, which is available to authorized users.