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Growth at elevated CO 2 concentrations leads to modified profiles of secondary metabolites in tobacco cv. SamsunNN and to increased resistance against infection with potato virus Y
Author(s) -
MATROS ANDREA,
AMME STEFFEN,
KETTIG BARBARA,
BUCKSORLIN GERHARD H.,
SONNEWALD UWE,
MOCK HANSPETER
Publication year - 2006
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2005.01406.x
Subject(s) - scopoletin , chemistry , nitrogen , salicylic acid , nicotiana tabacum , chlorogenic acid , secondary metabolite , inoculation , potato virus y , horticulture , botany , food science , virus , biochemistry , biology , plant virus , organic chemistry , gene , medicine , alternative medicine , pathology , virology
The effect of elevated CO 2 concentrations on the levels of secondary metabolites was investigated in tobacco plants grown under two nitrogen supply (5 and 8 m m NH 4 NO 3 ) and CO 2 conditions (350 and 1000 p.p.m.) each. High CO 2 resulted in a dramatic increase of phenylpropanoids in the leaves, including the major carbon‐rich compound chlorogenic acid (CGA) and the coumarins scopolin and scopoletin at both nitrogen fertilizations. This was accompanied by increased PAL activity in leaves and roots, which was even higher at the lower nitrogen supply. Hardly any change was observed for the structural phenolic polymer lignin and the sesquiterpenoid capsidiol. In contrast, elevated CO 2 led to clearly decreased levels of the main nitrogen‐rich constituent nicotine at the lower N‐supply (5 m m NH 4 NO 3 ) but not when plants were grown at the higher N‐supply (8 m m NH 4 NO 3 ). Inoculation experiments with potato virus Y (PVY) were used to evaluate possible ecological consequences of elevated CO 2 . The titre of viral coat‐protein was markedly reduced in leaves under these conditions at both nitrogen levels. Since PR‐gene expression and free salicylic acid (SA) levels remained unchanged at elevated CO 2 , we suggest that the accumulation of phenylpropanoids, for example, the major compound CGA and the coumarins scopolin and scopoletin may result in an earlier confinement of the virus at high CO 2 . Based on our results two final conclusions emerge. First, elevated CO 2 leads to a shift in secondary metabolite composition that is dependent on the availability of nitrogen. Second, changes in the pool of secondary metabolites have important consequences for plant–pathogen interactions as shown for PVY as a test organism.