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.
Clé
Carla
C
Laboratory of Plant Physiology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.
Hill
Lionel M
LM
Niggeweg
Ricarda
R
Martin
Cathie R
CR
Guisez
Yves
Y
Prinsen
Els
E
Jansen
Marcel A K
MA
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