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Identification of genes associated with chlorophyll accumulation in flower petals.

ABSTRACT: Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation.

SUBMITTER: Ohmiya A

PROVIDER: S-EPMC4254739 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Identification of genes associated with chlorophyll accumulation in flower petals.

Ohmiya Akemi A Hirashima Masumi M Yagi Masafumi M Tanase Koji K Yamamizo Chihiro C

PloS one 20141203 12

Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low c ...[more]

PMID: 25470367

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Project description:BackgroundTemperature is involved in the regulation of carotenoid accumulation in many plants. The floral color of sweet osmanthus (Osmanthus fragrans Lour.) which is mainly contributed by carotenoid content, is affected by temperature in autumn. However, the mechanism remains unknown. Here, to reveal how temperature regulates the floral color of sweet osmanthus, potted sweet osmanthus 'Jinqiu Gui' were treated by different temperatures (15 °C, 19 °C or 32 °C). The floral color, carotenoid content, and the expression level of carotenoid-related genes in petals of sweet osmanthus 'Jinqiu Gui' under different temperature treatments were investigated.ResultsCompared to the control (19 °C), high temperature (32 °C) changed the floral color from yellow to yellowish-white with higher lightness (L*) value and lower redness (a*) value, while low temperature (15 °C) turned the floral color from yellow to pale orange with decreased L* value and increased a* value. Total carotenoid content and the content of individual carotenoids (α-carotene, β-carotene, α-cryptoxanthin, β-cryptoxanthin, lutein and zeaxanthin) were inhibited by high temperature, but were enhanced by low temperature. Lower carotenoid accumulation under high temperature was probably attributed to transcriptional down-regulation of the biosynthesis gene OfPSY1, OfZ-ISO1 and OfLCYB1, and up-regulation of degradation genes OfNCED3, OfCCD1-1, OfCCD1-2, and OfCCD4-1. Up-regulation of OfLCYB1, and down-regulation of OfNCED3 and OfCCD4-1 were predicted to be involved in low-temperature-regulated carotenoid accumulation. Luciferase assays showed that the promoter activity of OfLCYB1 was activated by low temperature, and repressed by high temperature. However, the promoter activity of OfCCD4-1 was repressed by low temperature, and activated by high temperature.ConclusionsOur study revealed that high temperature suppressed the floral coloration by repressing the expression of carotenoid biosynthesis genes, and activating the expression of carotenoid degradation genes. However, the relative low temperature had opposite effects on floral coloration and carotenoid biosynthesis in sweet osmanthus. These results will help reveal the regulatory mechanism of temperature on carotenoid accumulation in the petals of sweet osmanthus.

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Identification of genes associated with chlorophyll accumulation in flower petals.

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Identification of genes associated with chlorophyll accumulation in flower petals.

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