A DIGE analysis of developing poplar leaves subjected to ozone reveals major changes in carbon metabolism

Abstract

Tropospheric ozone pollution is described as having major negative effects on plants, compromising plant survival. Carbon metabolism is especially affected. In the present work, the effects of chronic ozone exposure were evaluated at the proteomic level in developing leaves of young poplar plants exposed to 120 ppb of ozone for 35 days. Soluble proteins (excluding intrinsic membrane proteins) were extracted from leaves after 3, 14 and 35 days of ozone exposure, as well as 10 days after a recovery period. Proteins (pI 4 to 7) were analyzed by 2-D DIGE experiments, followed by MALDI-TOF-TOF identification. Additional observations were obtained on growth, lesion formation, and leaf pigments analysis. Although treated plants showed large necrotic spots and chlorosis in mature leaves, growth decreased only slightly and plant height was not affected. The number of abscised leaves was higher in treated plants, but new leaf formation was not affected. A decrease in chlorophylls and lutein contents was recorded. A large number of proteins involved in carbon metabolism were identified. In particular, proteins associated with the Calvin cycle and electron transport in the chloroplast were down-regulated. In contrast, proteins associated with glucose catabolism increased in response to ozone exposure. Other identified enzymes are associated with protein folding, nitrogen metabolism and oxidoreductase activity.

The physiological, transcriptional and genetic responses of an ozone- sensitive and an ozone tolerant poplar and selected extremes of their F 2 progeny

“…In contrast, some genotypes had over 90% damaged leaves later in the season. The marked increase in leaf abscission is consistent with previous work (Bohler et al, 2007;Karnosky et al, 1996;Woo and Hinckley, 2005), and serves to demonstrate the detrimental effect of ozone on leaf biomass. The treatment specific co-location of QTL for leaf number, leaf abscission and visible leaf damage with basal diameter suggests that these may be the responses resulting in reduced diameter growth.…”

“…No significant ozone effect on height was found but in contrast for basal stem diameter a small (À3.2%) but significant negative effect (F 1,132 ¼ 11.24, p < 0.001) of ozone was found similar to that reported in a meta-analysis of forest tree ozone responses (Wittig et al, 2009), indicating that ozone exposure is likely to impact biomass yield. This will require further confirmatory analysis from longer-term studies, but suggests that Populus biomass yield is likely to be detrimentally affected by future increased ozone concentrations, which are consistent with previous reports (Bohler et al, 2007;Bortier et al, 2000;Karnosky et al, 1996;Wittig et al, 2009;Woo and Hinckley, 2005). Such decreases in productivity are likely to be related to decreased photosynthetic activity (Bortier et al, 2000;Coleman et al, 1995;Degl'Innocenti et al, 2007;Lorenzini et al, 1999) and reduced leaf area (Wittig et al, 2009).…”

Tetracycline Accumulation in Pea Seedlings and its Effects on Proteome and Enzyme Activities

“…A two-fold increase (Fig. 4) in the concentration of Hsp 70 protein in pea seedlings growing with the antibiotic may indicate a protective function of the protein in folding cellular proteins, which may be damaged by free radicals (Agrawal et al, 2002;Bohler et al, 2007). Free radicals also stimulate the expression of ferritin (Fig.…”

“…Proteins OEE1 and OEE 2 are indispensable in electron transport in the process of photosynthesis (Mayfield et al, 1987). A decrease in RUBISCO activase, OEE1, OEE 2 was demonstrated in oxidative stress (Agrawal et al, 2002;Bohler et al, 2007;.…”

Quantitative Proteomics in Plants: Choices in Abundance

“…Therefore, DIGE is highly appropriate for comparative profiling of knockout, transgenic, or isogenic germplasm as well as defined pharmacological or stressinduced responses as recent reports suggest (Casati et al, 2005;Amme et al, 2006;Mooney et al, 2006;Hjerno et al, 2006;Hajduch et al, 2007;Keeler et al, 2007;Bohler et al, 2007). Another important consideration is that quantitative studies using 2-D gels in general, and 2-D DIGE in particular, can be performed with any plant species and are not restricted to plants with sequenced genomes.…”