Molecular markers for ozone stress isolated by suppression subtractive hybridization: specificity of gene expression and identification of a novel stress-regulated gene

Suppression subtractive hybridization was used to identify genes regulated by ozone (100 nmol mol(-1)) in Pisum sativum. One novel gene (named PsUod1) was found. In addition, mRNA levels for four genes (encoding lipid transfe r protein, pre-hevein-like protein, leucine-rich repeat protein, and diseas e-resistance response protein 230), which previously were shown to be regul ated by biotic stress, increased. Finally, mRNA species for two genes (enco ding extensin and pathogenesis-related protein 4A), previously shown to be regulated by ozone in other species, were found to increase in abundance. T he ozone-specificity of the expression of these genes was studied by using UV-B radiation. PsUod1 and the genes encoding extensin, leucine-rich repeat protein, and disease-resistance response protein 230, were differentially regulated when comparing ozone and UV-B. Moreover, the mRNA levels for exte nsin, leucine-rich repeat protein and disease-resistance response protein 2 30 all increased under NaCl and aluminium stress and after wounding, wherea s the message abundance for PsUod1 was unchanged under these stresses. Thus , in general, ozone caused changes similar to wounding, salt stress and alu minium stress, whereas UV-B radiation regulated gene expression differently .