Ueno, K., Ishiwa, S., Nakashima, H., Mizutani, M., Takikawa, H., Sugimoto, Y.: Regioselective and stereospecific hydroxylation of GR24 by Sorghum bicolor and evaluation of germination inducing activities of hydroxylated GR24 stereoisomers toward seeds of
Ueno, K., Ishiwa, S., Nakashima, H., Mizutani, M., Takikawa, H., Sugimoto, Y.: Regioselective and stereospecific hydroxylation of GR24 by Sorghum bicolor and evaluation of germination inducing activities of hydroxylated GR24 stereoisomers toward seeds of
复制标题
Ueno, K.、Ishiwa, S.、Nakashima, H.、Mizutani, M.、Takikawa, H.、Sugimoto, Y.：高粱对 GR24 的区域选择性和立体特异性羟基化以及羟基化 GR24 立体异构体的发芽诱导活性评估
DOI：
10.1016/j.bmc.2015.08.003
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发表时间：
2015
影响因子：
3.5
通讯作者：
Y.
中科院分区：
文献类型：
--
作者：
Ueno;K.;Ishiwa;S.;Nakashima;H.;Mizutani;M.;Takikawa;H.;Sugimoto;Y.
研究了应用最广泛的人工合成独脚金内酯（SL）GR 24在水培高粱（Sorghum bicolor）中的生物转化及羟基化后的GR 24立体异构体的生物活性。使用液相色谱-串联质谱与多反应监测（MRM）的提取物和分泌物的高粱根先前喂食GR 24的外消旋和非对映体混合物的分析，证实摄取GR 24，并建议其转化为单羟基化产物。通过与一系列合成的单羟基化GR 24类似物的色谱行为的直接比较，在根提取物和渗出物中鉴定了两种主要的GR 24代谢物，7-羟基-GR 24和8-羟基-GR 24。通过对GR 24立体异构体进行单独的饲养实验，发现其羟基化产物均来自2′-epi-GR 24，表明GR 24分子被高粱立体识别，而所有GR 24立体异构体的反式-4-羟基-GR 24异构体均以微量代谢产物的形式存在于分泌物中。羟基GR 24异构体对独脚金种子萌发的诱导作用大小顺序为C-8 > C-7 > C-6 > C-5 > C-4。相反，具有相同构型的列当醇的立体异构体，无论羟基化的位置，诱导发芽ofStriga gesnerioides。结果证实了以前的报告SL的结构要求，并归因于一个关键的作用，羟基化，但不是在AB部分的分子中的羟基的位置，在诱导ofS。苦苣苔种子萌发。
Bioconversion of GR24, the most widely used synthetic strigolactone (SL), by hydroponically grown sorghum (Sorghum bicolor) and biological activities of hydroxylated GR24 stereoisomers were studied. Analysis of extracts and exudates of sorghum roots previously fed with a racemic and diastereomeric mixture of GR24, using liquid chromatography–tandem mass spectrometry with multiple reaction monitoring (MRM), confirmed uptake of GR24 and suggested its conversion to mono-hydroxylated products. Two major GR24 metabolites, 7-hydroxy-GR24 and 8-hydroxy-GR24, were identified in the root extracts and exudates by direct comparison of chromatographic behavior with a series of synthetic mono-hydroxylated GR24 analogues. Separate feeding experiments with each of the GR24 stereoisomers revealed that the hydroxylated products were derived from 2′-epi-GR24, an evidence of sterical recognition of the GR24 molecule by sorghum.Trans-4-hydroxy-GR24 isomers derived from all GR24 stereoisomers were detected in the exudates as minor metabolites. The synthetic hydroxy-GR24 isomers induced germination of Strigahermonthicain decreasing order of C-8 > C-7 > C-6 > C-5 > C-4. In contrast the stereoisomers having the same configuration of orobanchol, irrespective of position of hydroxylation, induced germination ofStriga gesnerioides. The results confirm previous reports on structural requirements of SLs and ascribe a critical role to hydroxylation, but not to the position of the hydroxyl group in the AB part of the molecule, in induction ofS. gesnerioidesseed germination.