Leaf tissues of barley (Hordeum vulgare L. cv. Salome) respond to meth
yl jasmonate (JaMe) treatment with a characteristic pattern of gene ex
pression. Jasmonate-induced proteins (JIPs), such as leaf thionins (ji
p15 gene product) and ribosome-inactivating proteins (jip60 gene produ
ct), rapidly accumulate. Their genes are transiently transcriptionally
activated, as shown here by the determination of in-vitro transcripti
on rates in run-off assays. In contrast to jip genes, expression of ph
otosynthetic genes encoding the small subunit of ribulose-l,5-bisphosp
hate carboxylase/oxygenase (rbcS gene product) and a type III light-ha
rvesting chlorophyll-a/b-binding protein (LHCP; lhbC1 gene product), f
or example, was rapidly down-regulated in JaMe-treated barley leaves.
Despite decreasing rates of rbcS and lhbC1 gene transcription, their t
ranscripts were maintained in JaMe-treated leaf tissues for at least 3
6 h. Only at a later stage, was there a decline in the levels of rbcS
and lhbC1, but not jip, transcripts, suggesting a selective destabiliz
ation of photosynthetic mRNAs in JaMe-treated leaf tissues.