Active anthocyanin degradation in Brunfelsia calycina (yesterday–today–tomorrow) flowers

Abstract

Anthocyanins are the largest group of plant pigments responsible for colors ranging from red to violet and blue. The biosynthesis of anthocyanins, as part of the larger phenylpropanoid pathway, has been characterized in great detail. In contrast to the detailed molecular knowledge available on anthocyanin synthesis, very little is known about the stability and catabolism of anthocyanins in plants. In this study we present a preliminary characterization of active in planta degradation of anthocyanins, requiring novel mRNA and protein synthesis, in Brunfelsia calycina flowers. Brunfelsia is a unique system for this study, since the decrease in pigment concentration in its flowers (from dark purple to white) is extreme and rapid, and occurs at a specific and well-defined stage of flower development. Treatment of detached flowers with protein and mRNA synthesis inhibitors, at specific stages of flower development, prevented degradation. In addition, treatment of detached flowers with cytokinins delayed senescence without changing the rate of anthocyanin degradation, suggesting that degradation of anthocyanins is not part of the general senescence process of the flowers but rather a distinctive and specific pathway. Based on studies on anthocyanin degradation in wine and juices, peroxidases are reasonable candidates for the in vivo degradation. A significant increase in peroxidase activity was shown to correlate in time with the rate of anthocyanin degradation. An additional indication that oxidative enzymes are involved in the process is the fact that treatment of flowers with reducing agents, such as DTT and glutathione, caused inhibition of degradation. This study represents the first step in the elucidation of the molecular mechanism behind in vivo anthocyanin degradation in plants.

Carotenoid Cleavage Dioxygenase (CmCCD4a) Contributes to White Color Formation in Chrysanthemum Petals

“…Very few data are available concerning the relationship between pigment degradation and petal color. Vaknin et al (2005) suggested that active anthocyanin degradation occurs in the petals of Brunfelsia calycina, resulting in white color. However, the precise mechanism remains to be elucidated.…”

Semidominant Mutations in Reduced Epidermal Fluorescence 4 Reduce Phenylpropanoid Content in Arabidopsis

“…Little is known about the breakdown of these molecules; although it has been shown that in some species, anthocyanin catabolism is a regulated process that is enzymatically catalyzed (Vaknin et al 2005). Analysis of some Arabidopsis mutants has suggested that active turnover and catabolism of phenylpropanoid intermediates may be common.…”

An Intracellular Laccase is Responsible for the Epicatechin Mediated Anthocyanin Degradation in Litchi Fruit Pericarp

“…Anthocyanin accumulation is significantly induced in plants under stress conditions, such as high light intensity, low temperature, drought, or nutrition deficiency, and is degraded once the stress is eliminated (Winkel-Shirley, 2002;Rowan et al, 2009). Rapid anthocyanin degradation occurs in Brunfelsia calycina (yesterday-today-tomorrow) petals after flower opening (Zenner and Bopp, 1987;Vaknin et al, 2005). Anthocyanins are degraded during pear fruit maturity (Pyrus communis; Steyn et al, 2004) and throughout the senescence of litchi (Litchi chinensis; Zhang et al, 2001Zhang et al, , 2005 and blood citrus fruit (Barbagallo et al, 2007).…”