The regulatory role of shikimate in plant phenylalanine metabolism

P., Adams, Zachary; Ehlting, Jürgen; Edwards, Roderick

doi:10.1016/j.jtbi.2018.11.005

Cited by 53 publications

(35 citation statements)

References 31 publications

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“…CYP98 family members connected to lignin biosynthesis appear to prefer 4‐coumaroyl‐shikimate as a substrate (Table S1). It is plausible that shikimate was favored because this allowed metabolic regulation of the flux into G‐ and S‐lignin by the upstream shikimate pathway in order to maintain a sufficient phenylalanine pool for essential functions, such as protein biosynthesis (Schoch et al ., ; Adams et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Evolution of coumaroyl conjugate 3‐hydroxylases in land plants: lignin biosynthesis and defense

et al. 2019

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Summary Multiple adaptations were necessary when plants conquered the land. Among them were soluble phenylpropanoids related to plant protection and lignin necessary for upright growth and long‐distance water transport. Cytochrome P450 monooxygenase 98 (CYP98) catalyzes a rate‐limiting step in phenylpropanoid biosynthesis. Phylogenetic reconstructions suggest that a single copy of CYP98 founded each major land plant lineage (bryophytes, lycophytes, monilophytes, gymnosperms and angiosperms), and was maintained as a single copy in all lineages but the angiosperms. In angiosperms, a series of independent gene duplications and losses occurred. Biochemical assays in four angiosperm species tested showed that 4‐coumaroyl‐shikimate, a known intermediate in lignin biosynthesis, was the preferred substrate of one member in each species, while independent duplicates in Populus trichocarpa and Amborella trichopoda each showed broad substrate ranges, accepting numerous 4‐coumaroyl‐esters and ‐amines, and were thus capable of producing a wide range of hydroxycinnamoyl conjugates. The gymnosperm CYP98 from Pinus taeda showed a broad substrate range, but preferred 4‐coumaroyl‐shikimate as its best substrate. In contrast, CYP98s from the lycophyte Selaginella moellendorffii and the fern Pteris vittata converted 4‐coumaroyl‐shikimate poorly in vitro, but were able to use alternative substrates, in particular 4‐coumaroyl‐anthranilate. Thus, caffeoyl‐shikimate appears unlikely to be an intermediate in monolignol biosynthesis in non‐seed vascular plants, including ferns. The best substrate for CYP98A34 from the moss Physcomitrella patens was also 4‐coumaroyl‐anthranilate, while 4‐coumaroyl‐shikimate was converted to lower extents. Despite having in vitro activity with 4‐coumaroyl‐shikimate, CYP98A34 was unable to complement the Arabidopsis thaliana cyp98a3 loss‐of‐function phenotype, suggesting distinct properties also in vivo.

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Section: Introductionmentioning

confidence: 97%

Evolution of coumaroyl conjugate 3‐hydroxylases in land plants: lignin biosynthesis and defense

et al. 2019

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“…The secondary metabolism is a biosynthetic source of several interesting compounds useful to chemical, food, agronomic, cosmetics, and pharmaceutical industries. The secondary pathways are not necessary for the survival of individual cells but benefit the plant as a whole [1]. Another general characteristic of secondary metabolism is that found in a specific organism, or groups of organisms, and is an expression of the individuality of species [2].…”

Section: Introductionmentioning

confidence: 99%

Shikimic Acid Pathway in Biosynthesis of Phenolic Compounds

Santos-Sánchez¹,

Salas-Coronado²,

Hernández-Carlos³

et al. 2019

Plant Physiological Aspects of Phenolic Compounds

147

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Phenolic compounds are secondary metabolites found most abundantly in plants. These aromatic molecules have important roles, as pigments, antioxidants, signaling agents, the structural element lignan, and as a defense mechanism. The expression of phenolic compounds is promoted by biotic and abiotic stresses (e.g., herbivores, pathogens, unfavorable temperature and pH, saline stress, heavy metal stress, and UVB and UVA radiation). These compounds are formed via the shikimate pathway in higher plants and microorganisms. The enzymes responsible for the regulation of phenolic metabolism are known, and shikimic acid is a central metabolite. The shikimate pathway consists of seven reaction steps, beginning with an aldol-type condensation of phosphoenolpyruvic acid (PEP) from the glycolytic pathway, and D-erythrose-4-phosphate, from the pentose phosphate cycle, to produce 3-deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP). A key branchpoint compound is chorismic acid, the final product of the shikimate pathway. The shikimate pathway is described in this chapter, as well as factors that induce the synthesis of phenolic compounds in plants. Some representative examples that show the effect of biotic and abiotic stress on the production of phenolic compounds in plants are discussed.

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“…xylem decreased [55]. The relationship between HCT and C3'H also affected the proportion of different lignin monomers [56][57][58][59]. In this study, both C3'H and HCT in ZM were significantly highly expressed at 65 days after flowering, while only some of the expression levels in L7 were consistent with those in ZM.…”

Section: Discussionmentioning

confidence: 61%

Comparative transcriptome profiling provides insights into endocarp lignification of walnut (Juglans Regia L.)

Zhang

Sun

et al. 2020

Preprint

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Background Lignin is the main component of walnut endocarp, although we know little about the molecular mechanism of lignin formation in walnut endocarp. To understand the molecular mechanisms behind the two kinds of walnut phenotype and explore the genes involved into lignin formation, transcriptome sequencing was conducted in the walnut endocarp of the ‘Zanmei’ (ZM) and ‘Liaoning 7’ (L7) cultivars, which have different endocarp thicknesses. Compared with L7 walnut endocarp, the endocarp of ZM walnut is thicker, which decreases dehiscent nuts and compromised kernels.Results There are more differentially expressed genes (DEGs) in the ZM walnut cultivar. The DEGs involved in the phenylpropanoid biosynthesis were significantly upregulated in both cultivars 45 days after full bloom (DAFB), but more genes were upregulated in ZM than in L7. Moreover, the same DEGs showed different expression levels in the two cultivars. Most of the key genes in ZM had more different multiples than those in L7. Interestingly, when qRT-PCR was used to determine the expression of the key genes in different development stages of the two varieties, the expression patterns were different from those known in other species. Furthermore, transcription factors regulating secondary cell wall and lignin biosynthesis were identified. Quantitative real-time PCR results were consistent with transcriptome data.Conclusion In this study, transcriptome analysis was used to understand the molecular mechanisms of lignin formation in two walnut cultivars with different shell thickness. Several important key genes in the phenylpropanoid biosynthesis pathway were significantly different in the two cultivars, which may be the reason for the phenotypic differences. The analysis of transcription factors revealed that the regulation network in endocarp of walnut may be different from that of drupe such as apricot or peach. This study provides important candidate genes for exploring the complicated metabolic processes involved in the formation of walnut lignin.

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The regulatory role of shikimate in plant phenylalanine metabolism

Cited by 53 publications

References 31 publications

Evolution of coumaroyl conjugate 3‐hydroxylases in land plants: lignin biosynthesis and defense

Evolution of coumaroyl conjugate 3‐hydroxylases in land plants: lignin biosynthesis and defense

Shikimic Acid Pathway in Biosynthesis of Phenolic Compounds

Comparative transcriptome profiling provides insights into endocarp lignification of walnut (Juglans Regia L.)

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