月季功能性香气组分β-罗勒烯遗传变异的分子基础及其调控机理研究

Fragrance as the important ornamental trait of rose，one of its breeding objectives is the addition of functional aroma components. The acyclic monoterpene β-ocimene has antidepressant effect and can improve plant resistance. It is an important functional aroma component, but its molecular mechanism of biosynthesis is not yet clear. Earlier in the study, the content of β-ocimene in the rose variety 'Yellow Island' was found to be extremely low, but its bud mutant 'Past Feeling' was rich in β-ocimene. At the same time, the expression of RhNUDX1a/RhNUDX1b, which important to the monoterpene biosynthesis, was significantly up-regulated in the bud mutant. Therefore, it was speculated that RhNUDX1a/RhNUDX1b may related to the variation of β-ocimene biosynthesis. This study intends to use ' Yellow Island ' and ' Past Feeling' as the test materials. And plan to use techniques such as rose calli CRISPR gene editing, rose VIGS gene silencing, in vitro enzymatic activity verification and ChIP-PCR, to determine the sequence characteristics, gene function, and upstream transcription factors of RhNUDX1a/RhNUDX1b at the DNA, RNA and protein levels. Finally, this study will reveal the molecular basis and regulatory mechanisms involved in the genetic variation of β-ocimene unique biosynthesis. The result will enrich the molecular regulation network of rose monoterpenes biosynthesis, and provide important theoretical references for the fragrance molecules improvement breeding of rose.

花香为月季重要观赏性状，增加具有功能性的香气成分是育种目标之一。无环单萜β-罗勒烯具有抗抑郁功效还可提高植株抗性，是重要的功能性香气组分，但其生物合成的分子调控机制还不清晰。本研究前期发现，月季品种‘金银岛’中β-罗勒烯含量极低，但其芽变品种‘往日情怀’却富含β-罗勒烯。同时，芽变材料中单萜类合成关键基因RhNUDX1a/RhNUDX1b表达大幅上调，推测这可能与β-罗勒烯合成变异有关。本研究拟以‘金银岛’和‘往日情怀’为试材，计划在DNA、RNA及蛋白水平，利用月季愈伤组织CRISPR基因编辑、月季VIGS基因沉默、体外酶活检测和ChIP-PCR等技术，确定RhNUDX1a/RhNUDX1b的序列特征、基因功能和上游转录因子，揭示其参与β-罗勒烯独特生物合成遗传变异的分子基础及调控机制。该成果将丰富月季单萜类花香物质合成的分子调控网络，为月季花香分子改良育种提供重要理论参考。

花香为月季重要观赏性状，增加具有功能性的香气成分是育种目标之一。无环单萜β-罗勒烯具有抗抑郁功效还可提高植株抗性，是重要的功能性香气组分，但其生物合成的分子调控机制还不清晰。本项目以月季品种‘金银岛’及其芽变品种‘往日情怀’为试材，利用比较重测序方法筛选2个品种基因组的差异突变位点；利用转录组代谢组联合分析、蛋白体外酶活试验等方法，确定了β-罗勒烯是芽变品种‘往日情怀’香味变化的主要原因，鉴定到1个可以催化β-罗勒烯合成的重要基因RhNUDX1a；通过酵母单杂交筛库和功能分析得到了上游关键转录因子RcNF-YB；在115种植物基因组的范围内，探究NUDX基因家族的系统发育特征，讨论NUDX调控月季单萜类花香生物合成的进化背景。本项目成果将丰富月季单萜类花香物质合成的分子调控网络，为月季花香分子改良育种提供重要理论参考。