cDNAs induced by ozone from <i>Atriplex canescens</i> (saltbush) and their response to sulfur dioxide and water‐deficit

Abstract

Ozone effects on plant water relations have been reported to be similar to those of water‐deficit. The objective was to identify ozone‐inducible (OI) clones from Atriplex canescens (saltbush) and determine if they were also responsive to water‐deficit as well as SO 2 . cDNA clones derived from four different polyA RNAs which accumulate in 8‐month‐old shrub leaves exposed to ozone (0.2 μl I −1 , 6 h day −1 , 7 days) were isolated by differential screening, analyzed by northern blots, sequenced, and gene product homologies with other plant genes were determined. Clone OI12A‐3 has homology with wound‐inducible proteinase inhibitors, whereas clone OI8–3 protein is homologous to thiol proteases. Clones OI2–2 and OI14–3 putatively code for glycine‐rich proteins with repeated motifs (Gly‐Gly‐Gly‐Tyr‐Gly‐His) n and putative cell‐wall‐targeting signal peptides. Clone OI2–2 and particularly clone OI14–3 were also induced by both SO 2 and water‐deficit. These data indicate that woody plant genes associated with cell wall protein production and whose expression is induced by several stress factors may be responding to common oxidative stress pathways.