Distinctive Patterns of Flavonoid Biosynthesis in Roots and Nodules of Datisca glomerata and Medicago spp. Revealed by Metabolomic and Gene Expression Profiles.
Distinctive Patterns of Flavonoid Biosynthesis in Roots and Nodules of Datisca glomerata and Medicago spp. Revealed by Metabolomic and Gene Expression Profiles.
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DOI：
10.3389/fpls.2018.01463
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发表时间：
2018
影响因子：
5.6
通讯作者：
Berry AM
中科院分区：
文献类型：
--
作者：
Gifford I;Battenberg K;Vaniya A;Wilson A;Tian L;Fiehn O;Berry AM
被子植物的固氮枝(NFC)中的植物与固氮菌形成根瘤共生体。放线菌与放线菌形成共生关系，豆科植物(豆科植物)与蛋白细菌形成共生关系。黄酮类化合物是苯丙烷途径的次生代谢物，在豆科植物根瘤共生中发挥重要作用：作为信号分子，触发根瘤菌结瘤起始信号，并作为生长素极性运输抑制剂，在根瘤器官发生中起关键作用。为了探索类黄酮类化合物在NFC根瘤共生中潜在的更广泛的作用，我们结合了对放线菌寄主鸭茅和紫花苜蓿属豆科植物的根和根瘤的代谢学和转录组分分析。根据两种寄主中黄酮类代谢物的分布和苯丙烷类基因的表达模式来推断生物合成途径的模式，以确定相似和不同之处。两种寄主具有相似的类黄酮类，且根瘤中的类黄酮量普遍增加，但不同寄主的类黄酮量差异显著。虽然两种寄主都产生了柚皮苷元的衍生物，但鸭茅的代谢产物图谱表明，它侧重于松果膜蛋白的生物合成途径，以及丰富的黄酮醇，在共生中具有潜在的作用。此外，基因表达谱显示木质素/单甘醇途径的表达减少。相比之下，紫花苜蓿中的异黄酮类化合物含量非常丰富，其异黄酮类化合物的种类和来源都比鸭茅多。基因表达模式支持代谢途径的这些差异，特别是肉桂酸4-羟基酶(C4H)的表达差异明显，该酶在鸭茅中的表达水平显著低于其高表达的紫花苜蓿转录组。C4H是苯丙烷类化合物生物合成的主要限速步骤，它将松膜蛋白途径与木质素/单甘醇和柚皮苷元为基础的黄酮类分支分开。莽草酸O-羟基肉桂酰基转移酶是类黄酮生物合成和木质素/单甘醇途径之间的纽带，它在鸭茅中的表达水平也远低于在元宝草中的表达水平。我们的结果表明：(A)黄酮类化合物可能在放线菌根瘤中起主要作用，以及(B)不同寄主在共生过程中类黄酮类和苯丙烷生物合成的代谢通量的差异。
Plants within the Nitrogen-fixing Clade (NFC) of Angiosperms form root nodule symbioses with nitrogen-fixing bacteria. Actinorhizal plants (in Cucurbitales, Fagales, Rosales) form symbioses with the actinobacteria Frankia while legumes (Fabales) form symbioses with proteobacterial rhizobia. Flavonoids, secondary metabolites of the phenylpropanoid pathway, have been shown to play major roles in legume root nodule symbioses: as signal molecules that in turn trigger rhizobial nodulation initiation signals and acting as polar auxin transport inhibitors, enabling a key step in nodule organogenesis. To explore a potentially broader role for flavonoids in root nodule symbioses across the NFC, we combined metabolomic and transcriptomic analyses of roots and nodules of the actinorhizal host Datisca glomerata and legumes of the genus Medicago. Patterns of biosynthetic pathways were inferred from flavonoid metabolite profiles and phenylpropanoid gene expression patterns in the two hosts to identify similarities and differences. Similar classes of flavonoids were represented in both hosts, and an increase in flavonoids generally in the nodules was observed, with differences in flavonoids prominent in each host. While both hosts produced derivatives of naringenin, the metabolite profile in D. glomerata indicated an emphasis on the pinocembrin biosynthetic pathway, and an abundance of flavonols with potential roles in symbiosis. Additionally, the gene expression profile indicated a decrease in expression in the lignin/monolignol pathway. In Medicago sativa, by contrast, isoflavonoids were highly abundant featuring more diverse and derived isoflavonoids than D. glomerata. Gene expression patterns supported these differences in metabolic pathways, especially evident in a difference in expression of cinnamic acid 4-hydroxylase (C4H), which was expressed at substantially lower levels in D. glomerata than in a Medicago truncatula transcriptome where it was highly expressed. C4H is a major rate-limiting step in phenylpropanoid biosynthesis that separates the pinocembrin pathway from the lignin/monolignol and naringenin-based flavonoid branches. Shikimate O-hydroxycinnamoyltransferase, the link between flavonoid biosynthesis and the lignin/monolignol pathway, was also expressed at much lower levels in D. glomerata than in M. truncatula. Our results indicate (a) a likely major role for flavonoids in actinorhizal nodules, and (b) differences in metabolic flux in flavonoid and phenylpropanoid biosynthesis between the different hosts in symbiosis.
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影响因子：
3
作者：
Auguy, Florence;Abdel-Lateif, Khalid;Hocher, Valerie
通讯作者：
Hocher, Valerie
影响因子：
14.9
作者：
Kim S;Thiessen PA;Bolton EE;Chen J;Fu G;Gindulyte A;Han L;He J;He S;Shoemaker BA;Wang J;Yu B;Zhang J;Bryant SH
通讯作者：
Bryant SH
影响因子：
8.6
作者：
Djoumbou Feunang Y;Eisner R;Knox C;Chepelev L;Hastings J;Owen G;Fahy E;Steinbeck C;Subramanian S;Bolton E;Greiner R;Wishart DS
通讯作者：
Wishart DS
影响因子：
3.8
作者：
GRAMBOW, HJ;GRISEBACH, H
通讯作者：
GRISEBACH, H
影响因子：
7.4
作者：
DeFelice BC;Mehta SS;Samra S;Čajka T;Wancewicz B;Fahrmann JF;Fiehn O
通讯作者：
Fiehn O