Modulation of chlorogenic acid biosynthesis in Solanum lycopersicum; consequences for phenolic accumulation and UV-tolerance.
Chlorogenic acid (CGA) is one of the most abundant phenolic compounds in tomato (Solanum lycopersicum). Hydroxycinnamoyl CoA quinate transferase (HQT) is the key enzyme catalysing CGA biosynthesis in tomato. We have studied the relationship between phenolic accumulation and UV-susceptibility in transgenic tomato plants with altered HQT expression. Overall, increased CGA accumulation was associated with increased UV-protection. However, the genetic manipulation of HQT expression also resulted in more complex alterations in the profiles of phenolics. Levels of rutin were relatively high in both HQT gene-silenced and HQT-overexpressing plants raised in plant growth tunnels. This suggests plasticity in the flux along different branches of phenylpropanoid metabolism and the existence of regulatory mechanisms that direct the flow of phenolic precursors in response to both metabolic parameters and environmental conditions. These changes in composition of the phenolic pool affected the relative levels of UV-tolerance. We conclude that the capability of the phenolic compounds to protect against potentially harmful UV radiation is determined both by the total levels of phenolics that accumulate in leaves as well as by the specific composition of the phenolic profile.
Laboratory of Plant Physiology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.
Carla
C
Clé
Lionel M
LM
Hill
Ricarda
R
Niggeweg
Cathie R
CR
Martin
Yves
Y
Guisez
Els
E
Prinsen
Marcel A K
MA
Jansen
D002726:Chlorogenic Acid / Q000737:chemistry / Q000378:metabolism*; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D018551:Solanum lycopersicum / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry; D010636:Phenols / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry; D032322:Solanum / Q000378:metabolism* / Q000528:radiation effects*; D012995:Solubility; D013057:Spectrum Analysis
D010636:Phenols; D010936:Plant Extracts; D002734:Chlorophyll; D002726:Chlorogenic Acid