Gene structure and expression of the aspen cytosolic copper/zinc-superoxide dismutase (PtSodCc1)

Genomic and cDNA clones, corresponding to an ozone-induced cytosolic copper-zinc superoxide dismutase. were isolated from quaking aspen (Populus ri tremuloides Michx.). The cytosolic superoxide dismutase (SOD) appears to be part of a multi-gent: family in aspen and is interrupted by five introns in the: coding region. Northern blot analysis with a gene-specific probe revealed an increase in the expression of this gene in response to ozone in the leaves of an ozone-tolerant aspen clone, compared with an ozone-sensitive clone. CS;Cytosolic SOD transcript e?;expression levels in leaves were also found to increase significantly within 6 h of mechanical Hounding, after which the level of the transcript decreases. Under normal growing conditions, immature male and female aspen floral bud tissues contained the highest lec els of the cytosolic SOD gene transcript, whereas transcript levels were almost undetectable in older leaves. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.