镰刀菌诱导结香对白木香倍半萜合成酶基因表达与倍半萜含量的影响研究

Relationship between Expression of Sesquiterpene Synthase Gene and Sesquiterpene Content in Artificial Agarwood Induced by Fusarium sp. A2

目的研究镰刀菌诱导结香对白木香倍半萜合成酶（sesqui-TPS）表达的影响与倍半萜类化合物含量的动态变化。方法小孔滴注法进行镰刀菌诱导造香实验并割取造香前后12月内7个时间点的结香部位（沉香树脂）,采用实时荧光定量PCR法（q PCR）测定sesqui-TPS基因表达水平,气相色谱-质谱联用（GC-MS）技术分析倍半萜类化合物含量的动态变化。结果镰刀菌诱导白木香形成沉香2~12个月内sesqui-TPS基因相对表达量分别为10.85,0.793 1,6.484,611.4,5 800,4 211;人工诱导2个月前未检出倍半萜类次生代谢产物,4~12个月内共检出14个倍半萜类化合物,其相对百分含量分别为21.40%,25.52%,36.44%,32.40%和55.70%。结论镰刀菌诱导白木香结香过程中sesqui-TPS基因主要在后期响应伤害胁迫,其表达水平对促进倍半萜类成分生物合成具有滞后性,为进一步研究白木香结香过程中功能基因对萜类成分的生物合成途径调控作用奠定基础。

OBJECTIVE To explore the expression of sesquiterpene synthase （ gene sesqui-TPS） and dynamic change of sesquit- erpene content in the resin-deposited parts of the trunk of Aquilaria sinensis （ Lour. ） Gilg. induced by Fusarium sp. A2. METHODS Artificial agarwoods from Aquilaria sinensis were induced by Fusarium sp. A2 using pinhole instillation. The heartwood of Aquilaria sinensis without or with resin were extracted before induction and at 7 time points within one year after induction. The expression of ses- qui-TPS was detected by quantitative Real-time PCR. And then the dynamic change of sesquiterpene content in the tissues were ana- lyzed by gas chromatography-mass spectrometry （GC-MS）. RESULTS The relative expression of sesqui-TPS gene in the artificial agarwoods induced by Fusarium sp. A2 from 2 to 12 months were 10. 85,0. 793 1,6. 484,611.4,5 800,and 4 211 respectively. Ses- quiterpene secondary metabolites were not detected in the trunk at 2 months before artificial induction. Fourteen sesquiterpene were de- tected from 4 to 12 months, with relative percentages of 21.40%, 25.52%, 36.44%, 32. 40% and 55.70% at eaeh time point. CONCLUSION Sesqui-TPS gene is extremely sensitive to Fusarium sp. A2 treatment and responds to late damage. The expression of sesqui-TPS gene lags behind the accumulation of sesquiterpene component, which would provide a foundation for studies on regulation action of function gene for sesquiterpene biosynthase pathway during the formation of agarwood resin in A. sinensis.