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The Balance of Expression of Dihydroflavonol 4-reductase and Flavonol Synthase Regulates Flavonoid Biosynthesis and Red Foliage Coloration in Crabapples.

Tian J, Han ZY, Zhang J, Hu Y, Song T, Yao Y - Sci Rep (2015)

Bottom Line: Levels of anthocyanins and the transcript abundances of the anthocyanin biosynthetic gene, dihydroflavonol 4-reductase (McDFR) and the flavonol biosynthetic gene, flavonol synthase (McFLS), were assessed during the leaf development in two crabapple cultivars, 'Royalty' and 'Flame'.Further studies showed that overexpression of McDFR, or silencing of McFLS, increased anthocyanin production, resulting in red-leaf and red fruit peel phenotypes.These results suggest that the relative activities of McDFR and McFLS are important determinants of the red color of crabapple leaves, via the regulation of the metabolic fate of substrates that these enzymes have in common.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China [2] Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.

ABSTRACT
Red leaf color is an attractive trait of Malus families, including crabapple (Malus spp.); however, little is known about the molecular mechanisms that regulate the coloration. Dihydroflavonols are intermediates in the production of both colored anthocyanins and colorless flavonols, and this current study focused on the gene expression balance involved in the relative accumulation of these compounds in crabapple leaves. Levels of anthocyanins and the transcript abundances of the anthocyanin biosynthetic gene, dihydroflavonol 4-reductase (McDFR) and the flavonol biosynthetic gene, flavonol synthase (McFLS), were assessed during the leaf development in two crabapple cultivars, 'Royalty' and 'Flame'. The concentrations of anthocyanins and flavonols correlated with leaf color and we propose that the expression of McDFR and McFLS influences their accumulation. Further studies showed that overexpression of McDFR, or silencing of McFLS, increased anthocyanin production, resulting in red-leaf and red fruit peel phenotypes. Conversely, elevated flavonol production and green phenotypes in crabapple leaves and apple peel were observed when McFLS was overexpressed or McDFR was silenced. These results suggest that the relative activities of McDFR and McFLS are important determinants of the red color of crabapple leaves, via the regulation of the metabolic fate of substrates that these enzymes have in common.

No MeSH data available.


Related in: MedlinePlus

Transient expression of McFLS in crabapple.McFLS expression was suppressed by VIGS using the vector pTRV2-McFLS in ‘Royalty’, or the gene was overexpressed using the vector pBI121-McFLS in ‘Strawberry Jelly’. Crabapple leaves injected with the empty TRV and pBI121 vectors and infiltration buffer were used as controls. (A) Phenotype of McFLS silenced or McFLS overexpressing ‘Strawberry Jelly’ and ‘Royalty’ leaves. (B) Anthocyanin and flavonol contents at infiltration sites of crabapple leaves in μg/g fresh weight (FW). (C) Relative transcript expression levels in crabapple leaves around the infiltration sites were determined using qRT-PCR. Error bars indicate the standard error of the mean ± SE of three replicate measurements. Different letters above the bars indicate significantly different values (P < 0.05) calculated using one-way analysis of variance (ANOVA) followed by a Duncan’s multiple range test.
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f5: Transient expression of McFLS in crabapple.McFLS expression was suppressed by VIGS using the vector pTRV2-McFLS in ‘Royalty’, or the gene was overexpressed using the vector pBI121-McFLS in ‘Strawberry Jelly’. Crabapple leaves injected with the empty TRV and pBI121 vectors and infiltration buffer were used as controls. (A) Phenotype of McFLS silenced or McFLS overexpressing ‘Strawberry Jelly’ and ‘Royalty’ leaves. (B) Anthocyanin and flavonol contents at infiltration sites of crabapple leaves in μg/g fresh weight (FW). (C) Relative transcript expression levels in crabapple leaves around the infiltration sites were determined using qRT-PCR. Error bars indicate the standard error of the mean ± SE of three replicate measurements. Different letters above the bars indicate significantly different values (P < 0.05) calculated using one-way analysis of variance (ANOVA) followed by a Duncan’s multiple range test.

Mentions: To confirm the prediction, based on sequence homology, that McFLS is a key flavonol biosynthetic gene, we suppressed its expression in the leaves of ‘Strawberry Jelly’ using the VIGS system and the TRV vector. Approximately 14 days after Agrobacterium infiltration, red coloration was seen in the margin and other areas of the infected leaves (Fig. 5A). HPLC analysis confirmed that the levels of anthocyanins were significantly higher in the silenced leaves than in control leaves infiltrated with TRV alone (Fig. 5B). Finally, as seen in Fig. 4C, the expression of McPAL, McDFR and McANS was up-regulated in infected leaves.


The Balance of Expression of Dihydroflavonol 4-reductase and Flavonol Synthase Regulates Flavonoid Biosynthesis and Red Foliage Coloration in Crabapples.

Tian J, Han ZY, Zhang J, Hu Y, Song T, Yao Y - Sci Rep (2015)

Transient expression of McFLS in crabapple.McFLS expression was suppressed by VIGS using the vector pTRV2-McFLS in ‘Royalty’, or the gene was overexpressed using the vector pBI121-McFLS in ‘Strawberry Jelly’. Crabapple leaves injected with the empty TRV and pBI121 vectors and infiltration buffer were used as controls. (A) Phenotype of McFLS silenced or McFLS overexpressing ‘Strawberry Jelly’ and ‘Royalty’ leaves. (B) Anthocyanin and flavonol contents at infiltration sites of crabapple leaves in μg/g fresh weight (FW). (C) Relative transcript expression levels in crabapple leaves around the infiltration sites were determined using qRT-PCR. Error bars indicate the standard error of the mean ± SE of three replicate measurements. Different letters above the bars indicate significantly different values (P < 0.05) calculated using one-way analysis of variance (ANOVA) followed by a Duncan’s multiple range test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507444&req=5

f5: Transient expression of McFLS in crabapple.McFLS expression was suppressed by VIGS using the vector pTRV2-McFLS in ‘Royalty’, or the gene was overexpressed using the vector pBI121-McFLS in ‘Strawberry Jelly’. Crabapple leaves injected with the empty TRV and pBI121 vectors and infiltration buffer were used as controls. (A) Phenotype of McFLS silenced or McFLS overexpressing ‘Strawberry Jelly’ and ‘Royalty’ leaves. (B) Anthocyanin and flavonol contents at infiltration sites of crabapple leaves in μg/g fresh weight (FW). (C) Relative transcript expression levels in crabapple leaves around the infiltration sites were determined using qRT-PCR. Error bars indicate the standard error of the mean ± SE of three replicate measurements. Different letters above the bars indicate significantly different values (P < 0.05) calculated using one-way analysis of variance (ANOVA) followed by a Duncan’s multiple range test.
Mentions: To confirm the prediction, based on sequence homology, that McFLS is a key flavonol biosynthetic gene, we suppressed its expression in the leaves of ‘Strawberry Jelly’ using the VIGS system and the TRV vector. Approximately 14 days after Agrobacterium infiltration, red coloration was seen in the margin and other areas of the infected leaves (Fig. 5A). HPLC analysis confirmed that the levels of anthocyanins were significantly higher in the silenced leaves than in control leaves infiltrated with TRV alone (Fig. 5B). Finally, as seen in Fig. 4C, the expression of McPAL, McDFR and McANS was up-regulated in infected leaves.

Bottom Line: Levels of anthocyanins and the transcript abundances of the anthocyanin biosynthetic gene, dihydroflavonol 4-reductase (McDFR) and the flavonol biosynthetic gene, flavonol synthase (McFLS), were assessed during the leaf development in two crabapple cultivars, 'Royalty' and 'Flame'.Further studies showed that overexpression of McDFR, or silencing of McFLS, increased anthocyanin production, resulting in red-leaf and red fruit peel phenotypes.These results suggest that the relative activities of McDFR and McFLS are important determinants of the red color of crabapple leaves, via the regulation of the metabolic fate of substrates that these enzymes have in common.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China [2] Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.

ABSTRACT
Red leaf color is an attractive trait of Malus families, including crabapple (Malus spp.); however, little is known about the molecular mechanisms that regulate the coloration. Dihydroflavonols are intermediates in the production of both colored anthocyanins and colorless flavonols, and this current study focused on the gene expression balance involved in the relative accumulation of these compounds in crabapple leaves. Levels of anthocyanins and the transcript abundances of the anthocyanin biosynthetic gene, dihydroflavonol 4-reductase (McDFR) and the flavonol biosynthetic gene, flavonol synthase (McFLS), were assessed during the leaf development in two crabapple cultivars, 'Royalty' and 'Flame'. The concentrations of anthocyanins and flavonols correlated with leaf color and we propose that the expression of McDFR and McFLS influences their accumulation. Further studies showed that overexpression of McDFR, or silencing of McFLS, increased anthocyanin production, resulting in red-leaf and red fruit peel phenotypes. Conversely, elevated flavonol production and green phenotypes in crabapple leaves and apple peel were observed when McFLS was overexpressed or McDFR was silenced. These results suggest that the relative activities of McDFR and McFLS are important determinants of the red color of crabapple leaves, via the regulation of the metabolic fate of substrates that these enzymes have in common.

No MeSH data available.


Related in: MedlinePlus