离子注入和基因组重排选育产油微藻斜生栅藻及高产机理的研究

The first technical barrier that needs to be overcome before microalgae can be used as an economically viable biofuels feedstock is the breeding of elite microalga. In this program,according to the present status and breeding objectives of oleaginous microalgae breeding, the breeding strategy is explored. Ion beam implantation and genome shuffling are used in breeding of microalga Scenedesmus obliquus to improve its oil productivity. First, high throughout screening plate is established. Then the nitrogen ion beam implantation is adopted to mutate the microalga，and the mutant strains with high oil production will be carried toprotoplast fusion. After several cycles, high lipid yeilding strains will be obtained. The possible mechanism analysis for quality improvement of microalgae will be studied.This project will enrich the theory of high-lipid content microalgae breeding, and develop breeding technician.Its fulfillment will quicken the course of elite microalga breeding,accelerate the establishment of a bioenergy-focused microalgal culture collection and promote the commercial production of microalga bioenergy.The breeding strategy proposed in this project can be used for other economic microalgae.It is the first time that genome shuffling is proposed for rapid improvement of microalga phenotypes, and this is the innovation points of this project.

微藻是制备生物柴油的优质原料，但成本过高是目前微藻生物能源技术面临的一大瓶颈，优良藻种的选育是微藻生物柴油成本降低的首个关键环节。本项目根据产油微藻育种现状和存在的问题，结合育种目标,对高品质产油微藻的育种策略进行初探，提出建立离子注入诱变和基因组重排技术结合的育种体系。首先建立基于微孔板的高效的突变藻株筛选平台, 以斜生栅藻为出发株进行氮离子束注入诱变，构建基因组重排的初始亲本库；建立基因组重排平台，通过基因组重排技术得到生长速率和油脂含量明显提高的融合子，最后探讨表型得到优化的分子机制。该项目的完成有助于丰富产油微藻育种理论、拓展育种技术，对于促进高品质产油微藻选育进程、建立完善的藻种资源库、促进微藻能源实用化有重要意义。提出的采用离子注入诱变和基因组重排技术相结合、通过细胞水平的全基因组育种策略选育微藻的思路可以用于其它经济微藻的选育。创新点在于首次将基因组重排技术应用到藻种的改良。

微藻是制备生物柴油的重要原料，使用微藻进行油脂的生产涉及到多个关键科学问题，首要是优良藻种的选育。本课题针对产油微藻育种现状和问题，以斜生栅藻为模式藻进行了高品质产油微藻育种体系建立方面的探索，首次将离子注入和基因组重排相结合的技术应用到微藻育种。课题按照计划书拟研究内容展开了研究工作,达到了预期目标。通过低能离子注入和循环原生质体融合方法建立了斜生栅藻育种技术体系，实现了利用96孔板培养、96孔板生物和油脂测定等方法进行优质藻种的高通量筛选，获得4株优质突变株；研究了微藻培养过程二氧化碳和光强的交互作用，优化培养体系。我们还发现斜生栅藻能够利用木糖为碳源进行混养生长。该项目研究的成果将能够为优质藻种的选育提供新的思路和方法，具有十分重要的现实意义。