Effect of Treatment with Gibberellin, Gibberellin Biosynthesis Inhibitor, and Auxin on Steviol Glycoside Content in Stevia rebaudiana Bertoni
Effect of Treatment with Gibberellin, Gibberellin Biosynthesis Inhibitor, and Auxin on Steviol Glycoside Content in Stevia rebaudiana Bertoni
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赤霉素、赤霉素生物合成抑制剂和生长素处理对甜叶菊甜菊糖苷含量的影响
DOI：
10.1007/s12355-017-0561-3
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发表时间：
2017
期刊：
影响因子：
1.9
通讯作者：
Ohdoi Katsuaki
中科院分区：
文献类型：
--
作者：
Yoneda Yuki;Shimizu Hiroshi;Nakashima Hiroshi;Miyasaka Juro;Ohdoi Katsuaki
甜菊醇糖苷(SGS)是甜叶菊Bertoni中的天然化合物，甜度约为蔗糖的200-400倍。SGS的生物合成途径与赤霉素(GA)的生物合成途径相同，都是通过生成对位金桂酸来实现的。以往的研究表明，外源GA处理可上调SG相关基因的表达。然而，UGT85C2的转录水平在GA处理中仍然存在争议，UGT85C2参与了从甜菊糖单苷到甜菊醇的糖基化步骤，并暗示了SGS生物合成的速率限制步骤。为了更详细地了解SGS和GAs之间的关系，采用叶片渗入法对外源GA3、GA抑制剂Daminozide(DAM)和NAA(NAA)进行浓度梯度处理。结果表明，与未处理组相比，GA3、DAM或NAA处理组诱导的UGT85C2转录水平、甜菊糖苷和甜菊糖苷-A的总数显著上调。这些结果表明，GA生物合成途径影响SGS的数量，激素串扰发生在GA和生长素之间，从而改变SGS的数量。控制GA的生物合成可以考虑对SGS的产量进行调控。
Steviol glycosides (SGs) are natural compounds present inStevia rebaudiana(Bertoni) Bertoni, which are approximately 200–400 times sweeter than sucrose. A biosynthetic pathway of SGs shares a biosynthetic pathway of gibberellin (GA) through a formation ofent-kaurenoic acid. Previous studies have demonstrated that SG-related genes are upregulated by exogenous GA treatment. However, the transcription level ofUGT85C2,which is involved in a glycosylation step to steviol from steviolmonoside and suggests a rate-limiting step in the SGs biosynthesis, remains controversial in GA treatments. To have a detailed understanding of the relationship between SGs and GAs, a concentration gradient of exogenous GA3, GA inhibitor daminozide (DAM), and naphthaleneacetic acid (NAA) was used for treatment by the leaf infiltration method. Results showed that transcription level ofUGT85C2and the total number of stevioside and rebaudioside-A induced by GA3, DAM, or NAA treatment were significantly upregulated compared to an untreated group. These results suggest that the GA biosynthetic pathway affects the number of SGs and that hormonal crosstalk occurs between GA and auxin, which changes the number of SGs inS.rebaudiana. Controlling the GA biosynthesis could be considered to modulate the yield of SGs.