Cloning And Characterization Of A Rice (Oryza Sative) Dual-Specificity Kinase Gene

Mitogen-activated protein kinase (MAPK) cascades are evolutionary conserved from unicellular to complex eukaryotic organisms, and constitute one of the major signalling pathways involved in regulating a wide range of cellular activities from growth and development to cell death. The basic assembly of MAPK pathways is a three-component module conserved from yeast to humans. The MAPK module includes three kinases that establish a sequential activation pathway comprising a MAPK kinase kinase (MKKK), MAPK kinase (MKK), and MAPK.Currently, there have been at least 14 MKKK, 7 MKK, and 12MAPK identified in mammalian cells. Many plant MAP kinases are in response to a wide range of endogenous and environmental cues such as plant hormones, osmolarity, salinity and low- and high-temperature stresses. These cues greatly affected plant growth.Yeast Saccharomyces cerevisiae is a good model for study of MAPK signal pathway. In Saccharomyces cerevisiae, there are five MAPK pathways involved in mating, cell wall remodelling, nutrient deprivation, and responses to stress stimuli such as osmolarity changes. Component members of the yeast pathways have conserved counterparts in mammalian cells.MAPKs of rice (Oryza sativa L.), the most important of all food crops and an established monocot plant research model, have seen considerable progress mainly on their identication and characterization recently. To date, nine MAPKs (OsBWMK1, Os-BIMK1, OsMAP1, OsMAPK2, OsMSRMK2, Os-MAPK3, OsMSRMK3, OsMAPK4, and OsWJUMK1) and only one MAPKK, OsMEK1 have been identified from rice, mostly from the japonicatype cv Nipponbare. These studies have provided new information on the response and regulation of rice MAPKs, in particular on their possible role/function in the rice self-defense pathways.We identified and isolated a dual-specificity kinase, OsSTY kinase (O. sative serine/threonine/tyrosine kinase) from rice. OsSTY kinase encoded a protein of 417 amino acids with calculated molecular weight 45926 Da and isoelectric point 7.689. At the amino acid level, the OsSTY kinase showed 80% similarity and 71% identity to the Arabidopisis AtSTY kinase (a putative serine/threonine/tyrosine kinase), 77% similarity and 69% identity to peanut AhSTY kinase. OsSTY kinase possesses almost all the classical sequence motifs of a serine/threonine and tyrosine...