目的 研究茉莉酸甲酯(MeJA)和高温胁迫对白桦悬浮细胞三萜合成的影响。方法 利用不同浓度(25、50、100、150 μmol/L)MeJA和高温(50 ℃处理2 h)处理白桦细胞,进行生长量、细胞活力、抗逆酶活性、丙二醛和总三萜量及其合成关键酶基因相对表达量分析。结果 高温和MeJA的复合处理对白桦细胞三萜合成的诱导作用比单独的MeJA和高温处理更强。高温胁迫1 d后加入150 μmol/L的MeJA处理,细胞总三萜量最高,为76.6 mg/g,分别比空白对照、单独的MeJA和高温处理增加81.3%、159.9%和13.1%;三萜合成关键酶鲨烯合酶(SS)、鲨烯环氧酶(SE)、羽扇醇合酶(BPW)和β-香树酯醇合酶(BPY)基因的相对表达量也分别比空白对照增加297.1%、83.7%、1 032.6%和282.4%。高温胁迫1 d后加入MeJA处理,超氧化物歧化酶(SOD)和苯丙氨酸裂解酶(PAL)活性高于空白对照;生长量和细胞活力被抑制。结论 在高温胁迫后加入MeJA的复合处理可能通过影响白桦细胞生长量、细胞活力、丙二醛量和防御酶活性变化,调节三萜合成关键酶基因的表达,最终促进三萜物质的高效合成与积累。

Objective To investigate the effect of MeJA combined with high temperature stress in the treatment for the accumulation of triterpenoids in the birch (Betula platyphylla) suspension cells. Methods After MeJA (25, 50, 100, and 150 μmol/L)and high temperature (50 ℃ for 2 h) treatment, the cell growth, viability, content of MDA, the activity of defense enzyme, total triterpenoids content, and the gene expression levels of triterpenoids synthesis were measured. Results The combination of high temperature stress and MeJA treatment had a more powerful positive effect on the synthesis of triterpenoids than single MeJA or high temperature treatment in birch cells. Moreover, the concentration of total triterpenoids had the highest level when adding 150 μmol/L MeJA after the high temperature processing, was up to 76.6 mg/g, which was 81.3%, 159.9% and 13.1% higher than those in the blank control, individual MeJA treatment or the heat treatment alone respectively. Meanwhile, the gene expression levels of SS, SE, BPW, and BPY, related to the triterpenoids synthesis, had an increase about 297.1%, 83.7%, 1 032.6%, and 282.4% compare to the control. The MeJA after high temperature treatment enhanced the activity of SOD and PAL compared with the control, inhibited the cell growth and viability. Conclusion The treatment of MeJA after high temperature affects the cell growth, viability, and activity of defense enzyme, regulates the genes expression level of triterpenoids synthesis, and eventually could make cells to produce the triterpenoids substance effectively.

国家自然科学基金资助项目(31070531);国家基础科学人才培养基金(J1210053)