甘蓝型油菜BnaFACF基因影响种子脂肪酸组分的机制研究

How to further improve oil quality to meet the people’s demand change for vegetable oil nutrients is one of the eternal topic of rapeseed breeding, thus vegetable oil fatty acid composition formation mechanism is also a problem that must be solved by rapeseed basic molecular biology research. At present, the effect of a large class of low-molecular-weight cysteine-rich proteins (LCR) in biological process in plant gets more and more attention. We isolated and cloned a LCR gene BnaFACF from Brassica napus seeds developed 35 days after flowering, and it belongs to unknown-function IV subfamily of LCR family. By RNAi method to silencing the gene, the oleic acid relative content increased from around 60% in receptor XY15 seeds to about 82% in transgenic rapeseed seeds and the character is genetic stability. In order to answer this question, we intend to use the methods of cell biology, genetics, molecular biology and chemistry to reveal the molecular mechanism of BnaFACF gene regulating lipid synthesis, which provide a useful reference for artificial directional operation of rapeseed quality improvement.

如何根据人们对菜油营养成分需求的变化来进一步改良菜油品质是油菜育种的永恒话题之一，油菜籽中脂肪酸组分形成的机制也是油菜基础分子生物学研究必须解决的问题。当前，一大类低分子量富含半胱氨酸残基的蛋白质（LCR）在植物体的内生物过程中所发挥的作用越来越受到重视。我们从甘蓝型油菜开花后35天的种子中分离克隆到了一种LCR基因BnaFACF,它属于LCR家族的功能未知的第IV亚家族。通过RNAi技术证实沉默该基因可以将种子中的油酸含量由受体植物的60%左右提升到转基因油菜植株的82%左右，并能稳定遗传。那么，BnaFACF基因是如何改变种子存储油脂脂肪酸组分的？为了回答这一问题，我们拟采用细胞生物学、遗传学、分子生物学和化学的方法，从一个新视角来探讨BnaFACF基因调控油脂合成代谢的分子机制，为油菜品质改良的人工定向操作提供有益的参考。

提高含油量和改善菜油品质是当前油菜育种的重要目标之一。为了研究油菜种子发育与油脂代谢特性，我们利用抑制消减杂交技术从湘油15号中克隆了1个功能未知的基因BnaFACF，前期研究显示该基因可能与种子油脂代谢相关。为了阐释该基因的功能，本项目采用生物信息学、遗传学、细胞学、分子生物学及生物化学等技术方法，对BnaFACF的功能进行研究，结果表明：BnaFACF属于LCR家族的功能未知的第III亚家族；组织化学定位显示该基因在种子中特意表达，亚细胞定位在细胞质中油体上；进一步研究显示BnaFACF通过影响蔗糖代谢过程的中蔗糖磷酸酶SPP和转化酶INV两种酶的活性，改变蔗糖的浓度，进而改变磷酸激酶PK的表达水平，最终影响乙酰辅酶A的量，乙酰辅酶A量的变化再影响调控油脂的含量与脂肪酸组分的变化。本研究首次确定了低分子量富含半胱氨酸的BnaFACF具有调控油菜油脂代谢的作用，这也是首次确认功能未知的LCR家族第III亚家族成员的作用，为同亚家族基因功能的研究提供有益参考，同时为油菜种子产油量与菜油品质改良提供了新的分子标记辅助选育手段。