Temporal pattern of jasmonate-induced alterations in gene expression of barley leaves

Leaf tissues of barley (Hordeum vulgare L. cv. Salome) respond to methyl jasmonate (JaMe) treatment with a characteristic pattern of gene expression. Jasmonate-induced proteins (JIPs), such as leaf thionins (jip15 gene product) and ribosome-inactivating proteins (jip60 gene product), rapidly accumulate. Their genes are transiently transcriptionally activated, as shown here by the determination of in-vitro transcription rates in run-off assays. In contrast to jip genes, expression of photosynthetic genes encoding the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcS gene product) and a type III light-harvesting chlorophyll-a/b-binding protein (LHCP; lhbC1 gene product), for example, was rapidly down-regulated in JaMe-treated barley leaves. Despite decreasing rates of rbcS and lhbC1 gene transcription, their transcripts were maintained in JaMe-treated leaf tissues for at least 36 h. Only at a later stage, was there a decline in the levels of rbcS and lhbC1, but not jip, transcripts, suggesting a selective destabilization of photosynthetic mRNAs in JaMe-treated leaf tissues.