Molecular characterization of flavanone 3-hydroxylase gene and flavonoid accumulation in two chemotyped safflower lines in response to methyl jasmonate stimulation.
Molecular characterization of flavanone 3-hydroxylase gene and flavonoid accumulation in two chemotyped safflower lines in response to methyl jasmonate stimulation.
复制标题
两种化学型红花品系响应茉莉酸甲酯刺激的黄烷酮 3-羟化酶基因和类黄酮积累的分子特征
DOI：
10.1186/s12870-016-0813-5
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发表时间：
2016-06-10
影响因子：
5.3
通讯作者：
Guo M
中科院分区：
文献类型：
--
作者：
Tu Y;Liu F;Guo D;Fan L;Zhu Z;Xue Y;Gao Y;Guo M
研究背景在植物次生代谢产物中，类黄酮对植物的生长、发育和繁殖至关重要，对维持人体健康也有重要作用。红花是一种有花植物，其黄酮类化合物种类繁多，具有多种药理作用。然而，很少有人研究参与生物合成途径的基因，这些途径产生这些惊人的黄酮类化合物，特别是特征喹查尔酮。本研究首次克隆了红花黄烷酮3-羟化酶基因（F3 H），并对其参与黄酮类化合物生物合成途径进行了研究。亚细胞定位揭示了CtF 3 H在洋葱表皮细胞中的核定位和胞浆定位。CtF 3 H在大肠杆菌BL 21（DE 3）pLysS细胞中的pMAL-C5 x载体中的功能性表达导致以柚皮素为底物的二氢山奈酚的产生。此外，转录组表达的CtF 3 H显示出截然相反的表达模式，在喹喔查尔酮型红花系（橙黄色的花）和黄酮醇型红花系（白色花）的茉莉酸甲酯（MeJA），已被确定为类黄酮代谢物的激发子的外部刺激下。进一步的代谢产物分析表明，在喹查尔酮型红花品系中，喹查尔酮和黄酮醇类化合物如羟基异黄酮黄A、山萘酚-3-O-β-D-葡萄糖苷、山萘酚-3-O-β-芸香糖苷、芦丁、红花素和木犀草素等的含量有增加的趋势。MeJA处理后，黄酮醇型红花株系中山奈酚-3-O-β-芸香糖苷和山奈酚-3-O-β-D-葡萄糖苷的积累量增加。而其他黄酮醇类化合物，如山萘酚、二氢山萘酚和槲皮素-3-O-β-D-葡萄糖苷在黄酮醇类红花品系中的积累则对MeJA的刺激呈下降趋势。结论CtF 3 H在喹查尔酮类红花品系中的高表达与喹查尔酮和黄酮醇的积累有关，而其低表达不影响糖基化衍生物的积累增加（山奈酚-3-O-β-芸香糖苷和芸香苷）在黄酮醇型红花中的作用，但影响上游前体物质（D-苯丙氨酸、二氢山奈酚、山奈酚），部分揭示了CtF 3 H在不同表型和化学型红花品系中的功能。
BackgroundAmong secondary metabolites, flavonoids are particularly crucial for plant growth, development, and reproduction, as well as beneficial for maintenance of human health. As a flowering plant, safflower has synthesized a striking variety of flavonoids with various pharmacologic properties. However, far less research has been carried out on the genes involved in the biosynthetic pathways that generate these amazing flavonoids, especially characterized quinochalcones. In this study, we first cloned and investigated the participation of a presumed flavanone 3-hydroxylase gene (F3H) from safflower (CtF3H) in a flavonoid biosynthetic pathway.ResultsBioinformation analysis showed thatCtF3H shared high conserved residues and confidence with F3H from other plants. Subcellular localization uncovered the nuclear and cytosol localization ofCtF3H in onion epidermal cells. The functional expressions ofCtF3H inEscherichia coliBL21(DE3)pLysS cells in the pMAL-C5x vector led to the production of dihydrokaempferol when naringenin was the substrate. Furthermore, the transcriptome expression ofCtF3H showed a diametrically opposed expression pattern in a quinochalcone-type safflower line (with orange-yellow flowers) and a flavonol-type safflower line (with white flowers) under external stimulation by methyl jasmonate (MeJA), which has been identified as an elicitor of flavonoid metabolites. Further metabolite analysis showed the increasing tendency of quinochalcones and flavonols, such as hydroxysafflor yellow A, kaempferol-3-O-β-D-glucoside, kaempferol-3-O-β-rutinoside, rutin, carthamin, and luteolin, in the quinochalcone-type safflower line. Also, the accumulation of kaempferol-3-O-β-rutinoside and kaempferol-3-O-β-D-glucoside in flavonols-typed safflower line showed enhanced accumulation pattern after MeJA treatment. However, other flavonols, such as kaempferol, dihydrokaempferol and quercetin-3-O-β-D-glucoside, in flavonols-typed safflower line presented down accumulation respond to MeJA stimulus.ConclusionsOur results showed that the high expression ofCtF3H in quinochalcone-type safflower line was associated with the accumulation of both quinochalcones and flavonols, whereas its low expression did not affect the increased accumulation of glycosylated derivatives (kaempferol-3-O-β-rutinoside and rutin) in flavonols-typed safflower line but affect the upstream precursors (D-phenylalanine, dihydrokaempferol, kaempferol), which partly revealed the function ofCtF3H in different phenotypes and chemotypes of safflower lines.