Environmental and developmental effects on the biosynthesis of UV-B screening pigments in Scots pine (Pinus sylvestris L.) needles
| Autor: | Florian Kaffarnik, Werner Heller, Heinrich Sandermann, Harald K. Seidlitz, Josef Obermaier |
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| Rok vydání: | 2006 |
| Předmět: |
Coumaric Acids
Flavonols Ultraviolet Rays Physiology Metabolite Plant Science Cell wall Acylation Pigment chemistry.chemical_compound Biosynthesis Cell Wall Botany Glycosides chemistry.chemical_classification Esterification biology Scots pine Glycoside Pinus sylvestris Pigments Biological biology.organism_classification Enzyme chemistry Biochemistry Seedlings visual_art visual_art.visual_art_medium Seasons Acyltransferases |
| Zdroj: | Plant Cell Environ. 29, 1484-1491 (2006) |
| ISSN: | 1365-3040 0140-7791 |
| DOI: | 10.1111/j.1365-3040.2006.01518.x |
| Popis: | The major UV-B screening pigments of the epidermal layer of Scots pine (Pinus sylvestris) needles are flavonol 3-o-glycosides (F3Gs) esterified with hydroxycinnamic acids at positions 3" and 6". Acylation is the last step in biosynthesis and is catalysed by position-specific hydroxycinnamoyl transferases (3" and 6"HCT). The UV-B dependence of these enzyme activities was studied in primary needles of Scots pine seedlings grown under different UV-B conditions in environmentally controlled sun simulators. 6"HCT activity was induced upon UV-B irradiation while 3"HCT activity was not induced but showed high constitutive values. To investigate the biosynthesis of diacylated F3Gs during needle development under natural conditions, the HCT activities and metabolite contents were analysed in needles of field-grown mature pine trees. Accumulation of diacylated compounds as well as of 6"HCT activity occurred transiently in the first year of needle development only. In contrast, 3"HCT activity exhibited broad maxima in two consecutive years during needle growth. The data suggest that acylated F3Gs are first formed as soluble compounds which are then translocated into the cell wall to be bound by their hydroxycinnamoyl residues. |
| Databáze: | OpenAIRE |
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