Vacuolar phenolics

A second proof comes from wounding experiment of Pseudowintera colorata Raoul (Gould et al, 2002b). In contrast to green leaves, the red ones, enriched in vacuolar antho-cyanins, flavonols, dihydroflavonols, and HCAs, alleviate intensity and duration of the localized burst of H2O2 induced in palisade mesophyll cells by wounding. Vacuolar phenolics participate to scavenge ROS. 

Ferreres F, Figueiredo R, Bettencourt S, Carqueijeiro I, Oliveira J, Gil-Izquierdo A, Pereira DM, Valentao P, Andrade PB, Duarte P, Barceld AR, Sottomayor M (2011) Identification of phenolic compounds in isolated vacuoles of the medicinal plant Catharanthus roseus and their interaction with vacuolar class III peroxidase an H2O2 affair J Exp Bot 62 2841-2854... 

A second challenge to the vesicle model refers to the sorting capacity of the endomembrane system since it would predict that structurally related compounds destined to travel to the vacuole or the extracellular space need to be sorted in the ER or downstream of this compartment in a manner comparable to vacuolar or secretory proteins. In consequence, either specific receptors recognizing the different phytochemicals must be postulated or the synthesis of metabolites that need to be distributed to distinct compartments takes place on spatially separated complexes. Thus, the interface between phenolic biosynthesis, including distinct metabolons, and the loading of end products into primary transport vesicles, most probably at the ER surface, requires and surely will attract much research interest in the future. 

Schulz B, Frommer WB (2004) A plant ABC trans-pcater takes the lotus seat Science 306 622-625 Schulz M, Weissenbock G (1986) Isolation and separation of epidermal and mesophyll protoplasts from rye primary leaves - tissue specific characteristics of secondary phenolic product accumulation. Z Naturforsch [C] 41 22-27 Schumacher HM, Zenk MH (1988) Partial purification and characterization of dihydrobenzophen-anthridine oxidase fmmEschscholtzia californica cell suspension cultures. Plant Cell Rep 7 43 6 Sharma V, Strack D (1985) Vacuolar localization of 1-sinapolglucose 1-malate sinapoyltransferase in protoplasts from cotyledons oiRaphanus sati-vus. Planta 163 563-568... 

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