A putative functional MYB transcription factor induced by low temperature regulates anthocyanin biosynthesis in purple kale (Brassica Oleracea var. acephala f. tricolor)

Abstract

The purple kale (Brassica Oleracea var. acephala f. tricolor) is a mutation in kales, giving the mutant phenotype of brilliant purple color in the interior. Total anthocyanin analysis showed that the amount of anthocyanins in the purple kale was up to 1.73 mg g(-1) while no anthocyanin was detected in the white kale. To elucidate the molecular mechanism of the anthocyanin biosynthesis in the purple kale, we analyzed the expression of structural genes and some transcription factors associated with anthocyanin biosynthesis in the purple cultivar "Red Dove" and the white cultivar "White Dove". The result showed that nearly all the anthocyanin biosynthetic genes showed higher expression levels in the purple cultivar than in the white cultivar, especially for DFR and ANS, they were barely detected in the white cultivar. Interestingly, the fact that a R2R3 MYB transcription factor named BoPAP1 was extremely up-regulated in the purple kale and induced by low temperature attracted our attention. Further sequence analysis showed that BoPAP1 shared high similarity with AtPAP1 and BoMYB1. In addition, the anthocyanin accumulation in the purple kale is strongly induced by the low temperature stress. The total anthocyanin contents in the purple kale under low temperature were about 50-fold higher than the plants grown in the greenhouse. The expression of anthocyanin biosynthetic genes C4H, F3H, DFR, ANS and UFGT were all enhanced under the low temperature. These evidences strongly suggest that BoPAP1 may play an important role in activating the anthocyanin structural genes for the abundant anthocyanin accumulation in the purple kale.

The genome sequence of the most widely cultivated cacao type and its use to identify candidate genes regulating pod color

“…While MYB6 is less characterized, MYB113 is in a small clade known to act in complexes with basic helix-loop-helix (bHLH) proteins to activate genes encoding enzymes acting in late stages of flavonol biosynthesis. MYB variants cause pigmentation variation in potato, tomato, and pepper [48], as well as in kale [49]. Pigmentation in apple skin and flesh is also regulated by MYB transcription factors [50].…”

Anthocyanins accumulate in tartary buckwheat (Fagopyrum tataricum) sprout in response to cold stress

“…Because it is an important factor that influences anthocyanin biosynthesis, the effect of cold stress has been extensively studied for various plants (Crifò et al 2011;Zhang et al 2011Zhang et al , 2012. Numerous previous reports have demonstrated that cold stress can efficiently promote the accumulation of anthocyanins.…”

Experimental branch cooling increases foliar sugar and anthocyanin concentrations in sugar maple at the end of the growing season

“…Jeannette et al (2000) found that heat girdling at the base of maize (Zea mays) leaves caused an increase in foliar sucrose concentrations compared with controls and that the anthocyanin content of girdled leaves then increased considerably within 36 h. The mechanistic connection between sugar and anthocyanin concentrations has been bolstered by findings that sugars induce gene transcription required for anthocyanin biosynthesis via the shikimic acid pathway (Hara et al 2003). Indeed, the expression of a range of anthocyanin biosynthetic genes (e.g., CHS, CHI, C4H, F3H, DFR, ANS, and UFGT) are enhanced by lowtemperature exposure (Zhang et al 2011;Zhang et al 2012), with sugar signaling initiating the biochemical cascades that trigger this (e.g., Vitrac et al 2000;Hara et al 2003). In addition to their influence on anthocyanin biosynthesis, increases in sugar concentrations may play a significant role in triggering leaf senescence, especially the loss of chlorophyll in leaves (Wingler et al 1998).…”