H_2O_2介导内生真菌诱导子促进茅苍术细胞HMGR的活化和β-桉叶醇的生物合成

Promotion of HMGR activation and β-eudesmol biosynthesis in Atractylodes lancea suspension cell culture by hydrogen peroxide-mediated endopytic fungal elicitor

目的研究内生真菌诱导子对茅苍术悬浮细胞次生代谢途径关键酶活性的影响,探讨茅苍术次生代谢产物的诱导途径和诱导机制。方法将内生真菌诱导子添加到茅苍术悬浮细胞中,测定NADPH氧化酶和HMGR酶活性以及H2O2和β-桉叶醇的量。结果内生真菌Fusarium sp 5诱导子可提高NADPH氧化酶的活性,诱导氧化迸发,显著促进H2O2的积累,激活倍半萜类代谢途径中关键酶HMGR的活性,促进β-桉叶醇的生物合成,处理组的产量达到66.59μg/g,比对照组提高了257.6%。H2O2淬灭剂CAT和NADPH氧化酶抑制剂DPI可以阻断Fusarium sp 5诱导子对茅苍术悬浮细胞中HMGR的活化和β-桉叶醇合成的促进作用。外源H2O2溶液单独处理也能够触发茅苍术细胞中HMGR活化和β-桉叶醇的合成加强。结论H2O2是参与内生真菌诱导子诱发茅苍术细胞中β-桉叶醇合成所必需的信号分子,通过激活HMGR,从而触发β-桉叶醇的生物合成。

Objective To investigate the effect ofendophytic fungal elicitor on key enzyme activity, inducing pathway and mechanism involved in the secondary metabolites of Atractylodes lancea. Methods NADPH oxidase, HMGR activities, the concentration of hydrogen peroxide （H2O2） and β-eudesmol were determined by the co-culture of endophytic fungal elicitor and A. lancea suspension cell. Results NADPH oxidase activity was notably enhanced by Fusarium sp5 elicitor which could induce oxidative burst, significantly promote H2O2 accumulation, and activate HMGR in the sesquiterpenoids metabolic pathway. Compared with the control, the yield of β-eudesmol increased 257.6% and reached 66.59 μg/g. CAT and DPI could inhibit the HMGR activity and β-eudesmol biosynthesis in A. lancea cell induced by Fusarium sp5 elicitor. Exogenous H2O2 also induced HMGR and promoted the β-eudesmol biosynthesis. Conclusion H2O2 is necessary to induce β-eudesmol synthetic signal molecule by activating the HMGR.