Ultraviolet Radiation-Elicited Enhancement of Isoflavonoid Accumulation, Biosynthetic Gene Expression, and Antioxidant Activity in <i>Astragalus membranaceus</i> Hairy Root Cultures

Jiao, Jiao; Gai, Qing-Yan; Wang, Wei; Luo, Meng; Gu, Cheng‐Bo; Fu, Yujie; Ma, Wei

doi:10.1021/acs.jafc.5b03138

Cited by 53 publications

(45 citation statements)

References 51 publications

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“…Flavonoids are potent free radical-scavenging agents (Izaguirre et al, 2003). Moreover, UV-B radiation causing multiple cellular injuries has been shown to activate various signaling pathways, which ultimately result in the expression of genes responsible for the biosynthesis of important secondary metabolites (Jiao et al, 2015).…”

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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“…UV radiation (UV-A, UV-B, and UV-C) has been used as an abiotic elicitor in HRC of several species to enhance different groups of SMs [47][48][49][50][51][52]. Like other elicitors, dose, duration, plant species, etc.…”

Section: Abiotic Elicitors 221 Effect Of Uv Radiation On Sm Productionmentioning

confidence: 99%

Elicitation: A biotechnological tool for enhanced production of secondary metabolites in hairy root cultures

Halder

Sarkar

Jha

2019

Engineering in Life Sciences

223

116

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Elicitation is a possible aid to overcome various difficulties associated with the large‐scale production of most commercially important bioactive secondary metabolites from wild and cultivated plants, undifferentiated or differentiated cultures. Secondary metabolite accumulation in vitro or their efflux in culture medium has been elicited in the undifferentiated or differentiated tissue cultures of several plant species by the application of a low concentration of biotic and abiotic elicitors in the last three decades. Hairy root cultures are preferred for the application of elicitation due to their genetic and biosynthetic stability, high growth rate in growth regulator‐free media, and production consistence in response to elicitor treatment. Elicitors act as signal, recognized by elicitor‐specific receptors on the plant cell membrane and stimulate defense responses during elicitation resulting in increased synthesis and accumulation of secondary metabolites. Optimization of various parameters, such as elicitor type, concentration, duration of exposure, and treatment schedule is essential for the effectiveness of the elicitation strategies. Combined application of different elicitors, integration of precursor feeding, or replenishment of medium or in situ product recovery from the roots/liquid medium with the elicitor treatment have showed improved accumulation of secondary metabolites due to their synergistic effect. This is a comprehensive review about the progress in the elicitation approach to hairy root cultures from 2010 to 2019 and the information provided is valuable and will be of interest for scientists working in this area of plant biotechnology.

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“…At the last step, the formation of CAG from calycosin (CA) is catalyzed by uridine diphosphate glucose (UDP)-glucose: calycosin 7-O-glucosyltransferase (UCGT). For the last step, the formation of CAG from CAis catalyzed by uridine diphosphate glucose (UDP)-glucose: calycosin 7-O-glucosyltransferase (UCGT) [54,55].…”

Section: Introductionmentioning

confidence: 99%

“…In general, the most common protective mechanism against potentially damaging irradiation in plants is the biosynthesis of UV-absorbing compounds, such as phenolic compounds, flavonoids, and hydroxycinnamate esters [16]. The use of UV-B radiation is expected to induce the accumulation of CAG in A. mongholicus [55,58]. This could satisfy consumer demand for these naturally derived health-promoting products.…”

Section: Introductionmentioning

confidence: 99%

UV-B Radiation Largely Promoted the Transformation of Primary Metabolites to Phenols in Astragalus mongholicus Seedlings

Liu

Abozeid

et al. 2020

Biomolecules

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Ultraviolet-B (UV-B) radiation (280–320 nm) may induce photobiological stress in plants, activate the plant defense system, and induce changes of metabolites. In our previous work, we found that between the two Astragalus varieties prescribed by the Chinese Pharmacopoeia, Astragalus mongholicus has better tolerance to UV-B. Thus, it is necessary to study the metabolic strategy of Astragalus under UV-B radiation further. In the present study, we used untargeted gas chromatography-mass spectrometry (GC-MS) and targeted liquid chromatography-mass spectrometry (LC-MS techniques) to investigate the profiles of primary and secondary metabolic. The profiles revealed the metabolic response of Astragalus to UV-B radiation. We then used real-time polymerase chain reaction (RT-PCR) to obtain the transcription level of relevant genes under UV-B radiation (UV-B supplemented in the field, λmax = 313 nm, 30 W, lamp-leaf distance = 60 cm, 40 min·day−1), which annotated the responsive mechanism of phenolic metabolism in roots. Our results indicated that supplemental UV-B radiation induced a stronger shift from carbon assimilation to carbon accumulation. The flux through the phenylpropanoids pathway increased due to the mobilization of carbon reserves. The response of metabolism was observed to be significantly tissue-specific upon the UV-B radiation treatment. Among phenolic compounds, C6C1 carbon compounds (phenolic acids in leaves) and C6C3C6 carbon compounds (flavones in leaves and isoflavones in roots) increased at the expense of C6C3 carbon compounds. Verification experiments show that the response of phenolics in roots to UV-B is activated by upregulation of relevant genes rather than phenylalanine. Overall, this study reveals the tissues-specific alteration and mechanism of primary and secondary metabolic strategy in response to UV-B radiation.

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Ultraviolet Radiation-Elicited Enhancement of Isoflavonoid Accumulation, Biosynthetic Gene Expression, and Antioxidant Activity in Astragalus membranaceus Hairy Root Cultures

Cited by 53 publications

References 51 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

Elicitation: A biotechnological tool for enhanced production of secondary metabolites in hairy root cultures

UV-B Radiation Largely Promoted the Transformation of Primary Metabolites to Phenols in Astragalus mongholicus Seedlings

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