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Isoprene synthase expression and protein levels are reduced under elevated O 3 but not under elevated CO 2 (FACE) in field‐grown aspen trees
Author(s) -
CALFAPIETRA CARLO,
WIBERLEY AMY E.,
FALBEL TANYA G.,
LINSKEY AUTUMN R.,
MUGNOZZA GIUSEPPE SCARASCIA,
KARNOSKY DAVID F.,
LORETO FRANCESCO,
SHARKEY THOMAS D.
Publication year - 2007
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.1365-3040.2007.01646.x
Subject(s) - isoprene , carbon dioxide , chemistry , ozone , oxidizing agent , atmosphere (unit) , tropospheric ozone , carbon monoxide , environmental chemistry , biochemistry , organic chemistry , meteorology , physics , copolymer , catalysis , polymer
Emission of hydrocarbons by trees has a crucial role in the oxidizing potential of the atmosphere. In particular, isoprene oxidation leads to the formation of tropospheric ozone and other secondary pollutants. It is expected that changes in the composition of the atmosphere will influence the emission rate of isoprene, which may in turn feedback on the accumulation of pollutants and greenhouse gases. We investigated the isoprene synthase ( ISPS ) gene expression and the ISPS protein levels in aspen trees exposed to elevated ozone (O 3 ) and/or elevated carbon dioxide (CO 2 ) in field‐grown trees at the Aspen Free‐Air Carbon Dioxide Enrichment (FACE) experimental site. Elevated O 3 reduced ISPS mRNA and the amount of ISPS protein in aspen leaves, whereas elevated CO 2 had no significant effect. Aspen clones with different O 3 sensitivity showed different levels of inhibition under elevated O 3 conditions. The drop in ISPS protein levels induced a drop in the isoprene emission rate under elevated O 3 . However, the data indicated that other mechanisms also contributed to the observed strong inhibition of isoprene emission under elevated O 3 .