Pigmentation in the developing seed coat and seedling leaves of Brassica carinata is controlled at the dihydroflavonol reductase locus.
Flavonoid differences between near-isogenic lines of yellow- and brown-seeded Brassica carinata were used to identify a genetic block in seed coat and seedling leaf pigment biosynthesis. Seed coat pigment in the brown-seeded line consisted of proanthocyanidins (condensed tannins), while anthocyanin was absent. Dihydroquercetin, dihydrokaempferol, quercetin and kaempferol accumulated only in the mature seed coat of the yellow-seeded line, indicating dihydroflavonol reductase (DFR) as an element of genetic control in pigment biosynthesis. DFR transcripts from the developing seed coat in the yellow-seeded line were absent or less abundant at 5-30 days after pollination compared to transcript levels in the brown-seeded line. Seedling leaves of the yellow-seeded line exhibited reduced expression of DFR and contained less anthocyanin compared to the respective tissues from plants of the brown-seeded line when grown at 25/20 degrees C (day/night). Cooler (18/15 degrees C) growing temperatures affected seedling leaf pigmentation, mature seed coat colouration and DFR expression in the yellow-seeded line. Comparable brown-seeded line tissues were unaffected by these temperature changes. These results are suggestive of a temperature-sensitive regulator of DFR in the yellow-seeded line of Brassica carinata which ultimately affects the formation of pigments in the seedling leaves and in the mature seed coats.
Marles
M A Susan
MA
Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon SK, Canada S7N 0X2.
Gruber
Margaret Y
MY
Scoles
Graham J
GJ
Muir
Alister D
AD
D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D000872:Anthocyanins / Q000302:isolation & purification / Q000378:metabolism; D001937:Brassica / Q000201:enzymology / Q000235:genetics*; D002855:Chromatography, Thin Layer; D002934:Cinnamates / Q000302:isolation & purification; D015971:Gene Expression Regulation, Enzymologic; D013058:Mass Spectrometry / Q000379:methods; D009710:Nucleotide Mapping; D010858:Pigmentation / Q000235:genetics*; D010860:Pigments, Biological / Q000096:biosynthesis; D018515:Plant Leaves / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D019655:Quantitative Trait, Heritable; D011794:Quercetin / Q000031:analogs & derivatives / Q000302:isolation & purification; D018749:RNA, Plant / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D013696:Temperature
D000872:Anthocyanins; D002934:Cinnamates; D010860:Pigments, Biological; D018749:RNA, Plant; C029010:cinnamic acid; D011794:Quercetin; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase