Transcript expression profiling of stress responsive genes in response to short-term salt or PEG stress in sugarcane leaves.

Semi-quantitative RT-PCR based transcript expression of stress responsive genes was studied in leaves of sugarcane plants exposed to short-term (up to 24 h) salt (NaCl, 200 mM) or polyethylene glycol-PEG 8000 (20% w/v) stress. Transient increase in expression of NHX (sodium proton antiporter), SUT1 (sucrose transporter1), PDH (proline dhydrogenase) and CAT2 (catalase2) was observed in response to 2-4 h PEG stress. However, salt stress imposed repression of NHX, PDH and CAT2 at these time points. The transcript level of the delta (1)-pyrolline-5-carboxylate synthetase (P5CS) increased slightly in salt treatment while in response to the PEG stress, the gene expression increased at 4 h treatment but then decreased considerably by 80% at 24 h. The results thus indicated differential regulation of these stress responsive genes in response to salt or PEG stress in sugarcane. Further, the transcript expression data was compared with that available for the Arabidopsis homologs at Arabidopsis eFP Browser and Genevestigator V3 tools. Understanding transcript gene expression patterns of the stress responsive genes may provide insights into complex regulatory network of stress tolerance.