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A Malus crabapple chalcone synthase gene, McCHS, regulates red petal color and flavonoid biosynthesis.

Tai D, Tian J, Zhang J, Song T, Yao Y - PLoS ONE (2014)

Bottom Line: The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in 'Radiant'.Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines.We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China; College of Horticulture, Shanxi Agricultural University, Taigu, Shanxi, China.

ABSTRACT
Chalcone synthase is a key and often rate-limiting enzyme in the biosynthesis of anthocyanin pigments that accumulate in plant organs such as flowers and fruits, but the relationship between CHS expression and the petal coloration level in different cultivars is still unclear. In this study, three typical crabapple cultivars were chosen based on different petal colors and coloration patterns. The two extreme color cultivars, 'Royalty' and 'Flame', have dark red and white petals respectively, while the intermediate cultivar 'Radiant' has pink petals. We detected the flavoniods accumulation and the expression levels of McCHS during petals expansion process in different cultivars. The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in 'Radiant'. Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines. Moreover, the expression levels of several anthocyanin biosynthetic genes were higher in the transgenic McCHS overexpressing tobacco lines than in the control plants. A close relationship was observed between the expression of McCHS and the transcription factors McMYB4 and McMYB5 during petals development in different crabapple cultivars, suggesting that the expression of McCHS was regulated by these transcription factors. We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple.

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Relative expression profiles of potential MYB flavonoid activators during flower development.Real-time PCR was used to analyze the transcripts in petals of Malus cultivars ‘Royalty’ and ‘Radiant’, ‘Flame’, and all real time-PCR reactions were normalized using the Ct value corresponding to a Malus crabapple 18S ribosomal RNA gene (DQ341382). Stages referred to on the x axis are: (I) 6 days before full bloom; (II) 3 days before full bloom; (III) 1 day before full bloom; (IV) full bloom; and (V) 3 days after full bloom. Error bars correspond to the standard error of the mean ± SE of three replicate reactions.
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pone-0110570-g006: Relative expression profiles of potential MYB flavonoid activators during flower development.Real-time PCR was used to analyze the transcripts in petals of Malus cultivars ‘Royalty’ and ‘Radiant’, ‘Flame’, and all real time-PCR reactions were normalized using the Ct value corresponding to a Malus crabapple 18S ribosomal RNA gene (DQ341382). Stages referred to on the x axis are: (I) 6 days before full bloom; (II) 3 days before full bloom; (III) 1 day before full bloom; (IV) full bloom; and (V) 3 days after full bloom. Error bars correspond to the standard error of the mean ± SE of three replicate reactions.

Mentions: Transcriptional control of flavonoid biosynthesis is one of the best characterized regulatory systems in plants, and involves integrating both developmental and various biotic and abiotic stress signals and the promoters of flavonoid biosynthetic genes via the control of TFs [37]–[38]. Previously, we showed that anthocyanin biosynthetic genes are regulated by three classes of TFs [14]–[16]. To explore the transcriptional regulatory mechanisms of McCHS, we investigated the expression profiles of nine MYB TFs during the five petal developmental stages (Figure 6). For all three crabapple cultivars, the expressions of McMYB1, McMYB2 and McMYB14 were barely detected in petals, except at stage II. The expression levels of McMYB3 and McMYB7 showed a very similar profile in petals from the same cultivar and almost increaed with the development of crabapple petals. Furthermore, McMYB4 expression displayed a similar pattern to that of McMYB5 in petals from the same cultivars and decreased at the early development stages and increased at later development stages of crabapple petals. The profiles of McMYB6 and McMYB10 transcript accumulation suggested more specialized expression patterns between ‘Royalty’, ‘Radiant’ and ‘Flame’ petals. In ‘Royalty’ and ‘Flame’, the expressions of McMYB6 and McMYB10 were increased at the early development stages and decreased at later development stages of crabapple petals, but the transcriptions of McMYB6 and McMYB10 were increased with the development of petals in ‘Radiant’.


A Malus crabapple chalcone synthase gene, McCHS, regulates red petal color and flavonoid biosynthesis.

Tai D, Tian J, Zhang J, Song T, Yao Y - PLoS ONE (2014)

Relative expression profiles of potential MYB flavonoid activators during flower development.Real-time PCR was used to analyze the transcripts in petals of Malus cultivars ‘Royalty’ and ‘Radiant’, ‘Flame’, and all real time-PCR reactions were normalized using the Ct value corresponding to a Malus crabapple 18S ribosomal RNA gene (DQ341382). Stages referred to on the x axis are: (I) 6 days before full bloom; (II) 3 days before full bloom; (III) 1 day before full bloom; (IV) full bloom; and (V) 3 days after full bloom. Error bars correspond to the standard error of the mean ± SE of three replicate reactions.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4214706&req=5

pone-0110570-g006: Relative expression profiles of potential MYB flavonoid activators during flower development.Real-time PCR was used to analyze the transcripts in petals of Malus cultivars ‘Royalty’ and ‘Radiant’, ‘Flame’, and all real time-PCR reactions were normalized using the Ct value corresponding to a Malus crabapple 18S ribosomal RNA gene (DQ341382). Stages referred to on the x axis are: (I) 6 days before full bloom; (II) 3 days before full bloom; (III) 1 day before full bloom; (IV) full bloom; and (V) 3 days after full bloom. Error bars correspond to the standard error of the mean ± SE of three replicate reactions.
Mentions: Transcriptional control of flavonoid biosynthesis is one of the best characterized regulatory systems in plants, and involves integrating both developmental and various biotic and abiotic stress signals and the promoters of flavonoid biosynthetic genes via the control of TFs [37]–[38]. Previously, we showed that anthocyanin biosynthetic genes are regulated by three classes of TFs [14]–[16]. To explore the transcriptional regulatory mechanisms of McCHS, we investigated the expression profiles of nine MYB TFs during the five petal developmental stages (Figure 6). For all three crabapple cultivars, the expressions of McMYB1, McMYB2 and McMYB14 were barely detected in petals, except at stage II. The expression levels of McMYB3 and McMYB7 showed a very similar profile in petals from the same cultivar and almost increaed with the development of crabapple petals. Furthermore, McMYB4 expression displayed a similar pattern to that of McMYB5 in petals from the same cultivars and decreased at the early development stages and increased at later development stages of crabapple petals. The profiles of McMYB6 and McMYB10 transcript accumulation suggested more specialized expression patterns between ‘Royalty’, ‘Radiant’ and ‘Flame’ petals. In ‘Royalty’ and ‘Flame’, the expressions of McMYB6 and McMYB10 were increased at the early development stages and decreased at later development stages of crabapple petals, but the transcriptions of McMYB6 and McMYB10 were increased with the development of petals in ‘Radiant’.

Bottom Line: The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in 'Radiant'.Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines.We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China; College of Horticulture, Shanxi Agricultural University, Taigu, Shanxi, China.

ABSTRACT
Chalcone synthase is a key and often rate-limiting enzyme in the biosynthesis of anthocyanin pigments that accumulate in plant organs such as flowers and fruits, but the relationship between CHS expression and the petal coloration level in different cultivars is still unclear. In this study, three typical crabapple cultivars were chosen based on different petal colors and coloration patterns. The two extreme color cultivars, 'Royalty' and 'Flame', have dark red and white petals respectively, while the intermediate cultivar 'Radiant' has pink petals. We detected the flavoniods accumulation and the expression levels of McCHS during petals expansion process in different cultivars. The results showed McCHS have their special expression patterns in each tested cultivars, and is responsible for the red coloration and color variation in crabapple petals, especially for color fade process in 'Radiant'. Furthermore, tobacco plants constitutively expressing McCHS displayed a higher anthocyanins accumulation and a deeper red petal color compared with control untransformed lines. Moreover, the expression levels of several anthocyanin biosynthetic genes were higher in the transgenic McCHS overexpressing tobacco lines than in the control plants. A close relationship was observed between the expression of McCHS and the transcription factors McMYB4 and McMYB5 during petals development in different crabapple cultivars, suggesting that the expression of McCHS was regulated by these transcription factors. We conclude that the endogenous McCHS gene is a critical factor in the regulation of anthocyanin biosynthesis during petal coloration in Malus crabapple.

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