Flavonoid gene expression and UV photoprotection in transgenic and mutant Petunia leaves

Ryan, Ken G.; Swinny, Ewald; Markham, Kenneth R.; Winefield, Christopher

doi:10.1016/s0031-9422(01)00404-6

Cited by 246 publications

(148 citation statements)

References 25 publications

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“…The observation that MYB12 directly acts on the promoters of the flavonoid biosynthesis genes places MYB12 at the downstream end of the signaling chain that causes flavonol-specific gene activation. Now, we need to address the question whether MYB12 is involved in any of the many stress signaling pathways (Li et al, 1993;Christie et al, 1994;Dixon and Paiva, 1995;Ryan et al, 2001Ryan et al, , 2002) that result in flavonol accumulation. The myb12-ko plants described and characterized here will be instrumental in these experiments.…”

Section: Myb12 Exerts Its Regulatory Function Upon Flavonol Biosynthementioning

confidence: 99%

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

et al. 2005

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Comprehensive functional data on plant R2R3-MYB transcription factors is still scarce compared to the manifold of their occurrence. Here, we identified the Arabidopsis (Arabidopsis thaliana) R2R3-MYB transcription factor MYB12 as a flavonolspecific activator of flavonoid biosynthesis. Transient expression in Arabidopsis protoplasts revealed a high degree of functional similarity between MYB12 and the structurally closely related factor P from maize (Zea mays). Both displayed similar target gene specificity, and both activated target gene promoters only in the presence of a functional MYB recognition element. The genes encoding the flavonoid biosynthesis enzymes chalcone synthase, chalcone flavanone isomerase, flavanone 3-hydroxylase, and flavonol synthase were identified as target genes. Hence, our observations further add to the general notion of a close relationship between structure and function of R2R3-MYB factors. High-performance liquid chromatography analyses of myb12 mutant plants and MYB12 overexpression plants demonstrate a tight linkage between the expression level of functional MYB12 and the flavonol content of young seedlings. Quantitative real time reverse transcription-PCR using these mutant plants showed MYB12 to be a transcriptional regulator of CHALCONE SYNTHASE and FLAVONOL SYNTHASE in planta, the gene products of which are indispensable for the biosynthesis of flavonols.

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Section: Myb12 Exerts Its Regulatory Function Upon Flavonol Biosynthementioning

confidence: 99%

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

et al. 2005

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“…Flavonols also protect plants against UV light. In this regard, sunlight and UV-B light were shown to increase concentration of quercetin glycosides in grapevine berries (Price et al, 1995;Downey et al, 2007), petunia (Petunia hybrida;Ryan et al, 2002), mustard (Sinapis alba; Beggs et al, 1987), and soybean (Glycine max; Middleton and Teramura, 1993), while a flavonol synthase (FLS) mutant was shown to be incapable of flavonol production in response to UV radiation in Arabidopsis (Arabidopsis thaliana; Wisman et al, 1998). Interestingly, flavonol synthesis can also be induced by exposure to sunlight at stages during grape berry development when flavonols are normally not accumulating (Downey et al, 2004;Matus et al, 2009).…”

mentioning

confidence: 99%

The Grapevine R2R3-MYB Transcription Factor VvMYBF1 Regulates Flavonol Synthesis in Developing Grape Berries

et al. 2009

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Flavonols are important ultraviolet light protectants in many plants and contribute substantially to the quality and healthpromoting effects of fruits and derived plant products. To study the regulation of flavonol synthesis in fruit, we isolated and characterized the grapevine (Vitis vinifera 'Shiraz') R2R3-MYB transcription factor VvMYBF1. Transient reporter assays established VvMYBF1 to be a specific activator of flavonol synthase1 (VvFLS1) and several other promoters of grapevine and Arabidopsis (Arabidopsis thaliana) genes involved in flavonol synthesis. Expression of VvMYBF1 in the Arabidopsis mutant myb12 resulted in complementation of its flavonol-deficient phenotype and confirmed the function of VvMYBF1 as a transcriptional regulator of flavonol synthesis. Transcript analysis of VvMYBF1 throughout grape berry development revealed its expression during flowering and in skins of ripening berries, which correlates with the accumulation of flavonols and expression of VvFLS1. In addition to its developmental regulation, VvMYBF1 expression was light inducible, implicating VvMYBF1 in the control of VvFLS1 transcription. Sequence analysis of VvMYBF1 and VvFLS1 indicated conserved putative light regulatory units in promoters of both genes from different cultivars. By analysis of the VvMYBF1 amino acid sequence, we identified the previously described SG7 domain and an additional sequence motif conserved in several plant MYB factors. The described motifs have been used to identify MYB transcription factors from other plant species putatively involved in the regulation of flavonol biosynthesis. To our knowledge, this is the first functional characterization of a light-inducible MYB transcription factor controlling flavonol synthesis in fruit.

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“…Light is one of the major environmental factors that influences the flavonoid de novo biosynthesis, primarily short-wavelength UV solar radiation (Tegelberg et al, 2001;Ryan et al, 2002). The in vitro explants were grown in the absence of UV-B radiation because the light used had wavelengths in the range of 380-680 nm (Philips lamps -see: http://www.lighting.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Culture as a Stressful Factor Triggers Changes in Polyphenols, Flavonoids and Antioxidant Activity in Somatic Hybrids between Solanum tuberosum and S. bulbocastanum and their Respective Parents

Cruceriu

Molnár

Diaconeasa

et al. 2017

Not Bot Horti Agrobo

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Phenols, important secondary metabolites in plants, are responsible for specific defence mechanisms against abiotic stress, due to their strong antioxidant activity. Flavonoids, as part of phenolic group, are also involved in plant stress responses, being primarily responsible for photo-protection against UV solar radiation. Based on these premises, the plant response to optimized in vitro culture was evaluated, by quantifying the total polyphenolic content, the total flavonoid content and the antioxidant activity, both under in vitro and ex vitro conditions. Four closely related potato genotypes were analysed: the wild species Solanum bulbocatanum, S. tuberosum cv. 'Rasant' and two somatic hybrids between them. For all genotypes, both total polyphenolic content and antioxidant activity were increasing under optimized in vitro culture. The shoot responses were genotype dependent and the two somatic hybrids were intermediate between the parents both as morphology and reaction to in vitro stress. The somatic hybrid 1508/5, having morphology similar to potato, was reacting as the wild species, while the somatic hybrid 1508/2, with a similar morphology to the wild species was reacting as potato to in vitro stress. The somatic hybrid 1508/5 being also resistant to late blight is of interest for further use in pre-breeding. Total flavonoid content is decreasing under in vitro as compared to ex vitro conditions, UV-B radiation, the major trigger of flavonoid biosynthesis being absent in the fluorescent light. This study reveals the effect of in vitro culture on flavonoid content and details aspects of the biochemical parameters involved in plant in vitro stress.

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Flavonoid gene expression and UV photoprotection in transgenic and mutant Petunia leaves

Cited by 246 publications

References 25 publications

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

The Grapevine R2R3-MYB Transcription Factor VvMYBF1 Regulates Flavonol Synthesis in Developing Grape Berries

In Vitro Culture as a Stressful Factor Triggers Changes in Polyphenols, Flavonoids and Antioxidant Activity in Somatic Hybrids between Solanum tuberosum and S. bulbocastanum and their Respective Parents

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