Abstract: A putative protein kinase gene was isolated from Oryza rufipogon using the OsMKK1 as template for primer synthesis. This gene was used to analyse the involvement of signal molecules and hormones in signal transduction of mitogen-activated protein kinase. The 352 amino acids long MAPK has a molecular weight of 37 kDa and a pI value of 6.1. The gene sequence contained a dual-phosphorylation activation motif TDY (Thr-Asp-Tyr) and four activity domains (catalytic loop, activation loop, ATP binding site and substrate binding site). The 5’UTR of the gene was also analysed and was shown to contain the MYBCORE, ERE, GT-1 and GATA box, all of which have a role to play in MAPK function. Here we have treated the OrMKK1 lines with Jasmonic Acid (JA), salicylic acid (SA), ethylene (ET), benzothiadiazole (BTH) and abscisic acid (ABA) to determine the involvement of these molecules and hormones in MAPK signal transduction. OrMKK1 gene was induced by JA, SA, BTH and ET but was delayed and weak in ABA. The highest level of expression is seen in JA treated plants. The transcript level of this gene was also studied in various tissues and organs of rice and the results show that the gene is developmentally regulated as clearly seen from the Northern analysis conducted on rice tissues. The results from this study suggest that OrMKK1 may be activated by signal molecules and hormones and this gene may play a role in the plant defense mechanism.