Metabolic engineering: prospects for crop improvement through the genetic manipulation of phenylpropanoid biosynthesis and defense responses — a review

Dixon, Richard A.; Lamb, Chris; Masoud, Sameer; Sewalt, Vincent; Paiva, Nancy L.

doi:10.1016/s0378-1119(96)00327-7

Cited by 202 publications

(98 citation statements)

References 67 publications

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“…The ubiquitous occurrence, complex diversity, and diverse functions of flavonoids have made them suitable and effective targets for genetic engineering to alleviate the demands for limited natural resources. The in situ levels of major subgroups of flavonoids like chalcones and stilbenes have been increased because of their putative health benefits and prospective roles as defense agents of plants against various pathogens (Dixon et al, 1996). Owing to the endemic and endangered (Rokaya et al, 2012) nature of R. emodi and being a high-altitude medicinal herb not amenable to cultivation at low altitudes, it is quite indispensable to embark on a metabolic engineering program for enhanced and purposeful production of its characteristic phytoconstituents.…”

Section: Discussionmentioning

confidence: 99%

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases

et al. 2016

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Plants effectively defend themselves against biotic and abiotic stresses by synthesizing diverse secondary metabolites, including health-protective flavonoids. These display incredible chemical diversity and ubiquitous occurrence and confer impeccable biological and agricultural applications. Chalcone synthase (CHS), a type III plant polyketide synthase, is critical for flavonoid biosynthesis. It catalyzes acyl-coenzyme A thioesters to synthesize naringenin chalcone through a polyketidic intermediate. The functional divergence among the evolutionarily generated members of a gene family is pivotal in driving the chemical diversity. Against this backdrop, this study was aimed to functionally characterize members of the CHS gene family from Rheum emodi, an endangered and endemic high-altitude medicinal herb of northwestern Himalayas. Two full-length cDNAs (1,179 bp each), ReCHS1 and ReCHS2, encoding unique paralogs were isolated and characterized. Heterologous expression and purification in Escherichia coli, bottom-up proteomic characterization, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry analysis, and enzyme kinetic studies using five different substrates confirmed their catalytic potential. Phylogenetic analysis revealed the existence of higher synonymous mutations in the intronless divergents of ReCHS. ReCHS2 displayed significant enzymatic efficiency (V max /K m ) with different substrates. There were significant spatial and altitudinal variations in messenger RNA transcript levels of ReCHSs correlating positively with metabolite accumulation. Furthermore, the elicitations in the form of methyl jasmonate, salicylic acid, ultraviolet B light, and wounding, chosen on the basis of identified cis-regulatory promoter elements, presented considerable differences in the transcript profiles of ReCHSs. Taken together, our results demonstrate differential propensities of CHS paralogs in terms of the accumulation of flavonoids and their relative substrate selectivities.Plants, as ground-anchored sessile creatures, invest significant amounts of energy in the production of secondary metabolites to combat environmental pressures. These metabolites often are produced through complex and highly regulated biosynthetic pathways under the influence of different enzymatic machineries. One of the important classes of secondary metabolites is phenylpropanoids. These represent a significant proportion of secondary metabolites, encompassing nearly 20% of total carbon in the terrestrial biosphere. Flavonoids exhibit remarkable chemical diversity and ubiquitous occurrence and play an important role in many aspects of plant development, like flower coloration, photoprotection, pollen development, cell wall growth, and response to stress conditions like UV light protection, herbivory, wounding, interaction with soil microbes, and defense against pathogens (Yu and Jez, 2008;Pandey et al., 2015). Apart from performing numerous imperative roles in plants, flavonoids also have been reported as poten...

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Section: Discussionmentioning

confidence: 99%

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases

et al. 2016

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“…There is considerable interest in the potential for genetic manipulation of lignin levels and/or composition to help improve digestibility of forages and pulping properties of trees (Whetten and Sederoff, 1991;Boudet and GrimaPettenati, 1996;Dixon et al, 1996). Lignin levels increase with progressive maturity in stems of forage crops, including legumes such as alfalfa (Jung et al, 1997b) and in grasses such as tall fescue (Buxton and Redfearn, 1997).…”

Section: Introductionmentioning

confidence: 99%

Downregulation of Caffeic Acid 3-O-Methyltransferase and Caffeoyl CoA 3-O-Methyltransferase in Transgenic Alfalfa: Impacts on Lignin Structure and Implications for the Biosynthesis of G and S Lignin

et al. 2001

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“…5B, the transcriptional expression of PgCCR in response to salicylic acid, was strongly expressed at 48hr post treatment in hairy root. Lignifications can be important component of the defense response leading to resistance 10,11) . In the case of pathogen attack, stimulation of enzyme activities involved in the more specific lignin pathway was correlated with increased lignin synthesis 12) .…”

Section: Differential Expressions Of the Pgccr Under Various Abiotic mentioning

confidence: 99%

Isolation and Characterization of Cinnamoyl-CoA Reductase Gene from Panax ginseng C. A. Meyer

2008

Journal of Ginseng Research

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: Cinnamoyl-CoA reductase (CCR, EC 1.2.1.44) catalyses the reduction of cinnamic acid CoA esters into their corresponding aldehydes, the first step of the phenylpropanoid pathway specially dedicated to monolignol biosynthesis. A cDNA clones encoding CCR have been isolated from Panax ginseng C.A. Meyer and its expression was investigated in response to abiotic stresses. The cDNA, designated PgCCR which is 865 nucleotides long and has an open reading frame of 590 bp with a deduced amino acid sequence of 176 residues. The PgCCR encoded protein possesses substantial homology with CCRs isolated and cloned from other sources; the highest identity (51.8%) was observed with CCR from Tomato (Lycopersicon esculentum). Under various stress conditions, expression patterns of the PgCCR were highly induced in adventitious and hairy roots by several abiotic stresses. These results indicated that PgCCR plays protective role against diverse environmental stresses.

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Metabolic engineering: prospects for crop improvement through the genetic manipulation of phenylpropanoid biosynthesis and defense responses — a review

Cited by 202 publications

References 67 publications

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases

Downregulation of Caffeic Acid 3-O-Methyltransferase and Caffeoyl CoA 3-O-Methyltransferase in Transgenic Alfalfa: Impacts on Lignin Structure and Implications for the Biosynthesis of G and S Lignin

Isolation and Characterization of Cinnamoyl-CoA Reductase Gene from Panax ginseng C. A. Meyer

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