H2O2调控白木香结香过程中细胞程序性死亡的机理

Agarwood is the fragrant resin-infused wood that formed in Aquilaria species which are affected by external factors. It may be the most prized non-timber forest product that widely used in medicines、fragrances and religious ceremonies. Reactive oxygen(ROS) is a very important signal molecule to stress-induced programmed cell death(PCD) in plants ,but the the mechanism of ROS regulation of cell death is still a mystery.Our previous study found that PCD is involved in the formation of agarwood, and hydrogen peroxide can induce PCD. In order to further study the mechanism of hydrogen peroxide regulation in PCD,the content and cellular localization of hydrogen peroxide during agarwood formation will be studied via electron microscope cytochemistry technique and biochemistry. At the same time, the expression patterns of control genes of PCD will be analyzed by RNA-seq and qRT-PCR. And finally explore the molecular mechanism of hydrogen peroxide regulation of PCD in plant. This research will help to reveal the regulation mechanism of PCD in plants,and provide theoretical guidance for better agarwood-inducing technique .

沉香为珍稀药材和名贵香料，是白木香等沉香属植物受伤害后诱导产生的含有树脂的木材。活性氧（H2O2、O2-等）是胁迫诱导植物细胞程序性死亡（Programmed cell death, PCD）的重要信号分子，但是活性氧调控植物PCD的分子机理还不清楚。我们发现，PCD参与了沉香的形成，而H2O2可以诱导PCD的产生。为了深入研究H2O2调控白木香结香过程中PCD的作用机制，本项目拟在前期工作的基础上，运用细胞化学、生理生化等方法，系统研究白木香受到伤害后H2O2细胞学定位及含量的动态变化；同时利用转录组测序和实时荧光定量PCR技术，分析PCD相关基因的表达模式，初步解析H2O2调控PCD的分子机理。本研究的开展，有助于解析植物PCD的调控机制，同时为研发更加高效、稳定的人工结香技术提供一定的理论依据。

白木香只有在伤害胁迫下才能产生沉香，是典型的诱导型药用植物。过氧化氢是逆境胁迫条件下植物细胞启动程序性死亡的重要信号分子。本研究首先从组织解剖学角度明确了白木香茎内的木间韧皮部和木射线是沉香树脂形成和积累的主要场所，其次运用TUNEL检测和DAPI染色等方法从树体层面证明了细胞程序性死亡参与了伤害诱导白木香形成沉香的过程。在此基础上运用生理生化和分子生物学等手段证明伤害可导致白木香茎内过氧化氢含量的升高，进而诱导沉香萜类基因及细胞程序性死亡相关基因的上调，并初步证明功能性的末端氧化酶可促进白木香茎在受到伤害后过氧化氢的爆发，但延迟细胞程序性死亡相关基因的上调。研究结果有助于全面解析伤害诱导白木香启动防御反应形成沉香的理论，为研发更为高效的人工结香技术提供科学依据。