Characterization of mitogen activated protein kinases (MAPKs) in the Curcuma longa expressed sequence tag database

Abstract

Mitogen activated protein kinase (MAPK) cascades are universal signal transduction modules that play crucial role in plant growth and development as well as biotic and abiotic stress responses. 20 and 17 MAPKs have been characterized in Arabidopsis and rice respectively, which are used for identification of the putative MAPKs in other higher plants. However, no MAPK gene sequences have yet been characterized for asexually reproducing plants. We describe the analysis of MAPK EST sequences from Curcuma longa (an asexually reproducible plant of great medicinal and economic significance). The four Curcuma MAPKs contains all 11 MAPK conserved domains and phosphorylation-activation motif, TEY. Phylogenetic analysis grouped them in the subgroup A and C as identified earlier for Arabidopsis. The Curcuma MAPKs identified showed high sequence homology to rice OsMPK3, OsMPK4 and OsMPK5 suggesting the presence of similar key element in signaling biotic and abiotic stress responses. Although further in vivo and in vitro analysis are required to establish the physiological role of Curcuma MAPKs, this study provides the base for future research on diverse signaling pathways mediated by MAPKs in Curcuma longa as well as other asexually reproducing plants.

Keywords: Curcuma longa; MAPKs; TBLASTN; expressed sequence tags.

Figure 1

Domain scan result for Curcuma longa MAPK sequence CL.CON. 1447. A distinct protein kinase domain was found with MAP kinase signature sequence, ATP binding site and serine/threonine protein kinase active site.

Figure 2

Phylogenetic tree of MAPKs from Curcuma longa and other higher plants. Letters A-D on the right indicates different groups of MAPKs. The protein sequences of the MAPKs used for construction of the tree are listed in the GenBank database under the following accession numbers: OsMPK5 (AF479883), TaMAPK (ABS11090), AtMPK3 (BAA04866), OsMPK1 (AB183398), ZmMPK5 (AB016802), ZmSIMK (DQ422149), OsMPK2 (BAC99508), AtMPK4 (AEE82016), NtMAPK4 (BAE46985), ZmMPK7 (DQ295030), OsMPK3 (AAG40581), AtMPK2 (BAA03536), OsMPK7 (AK099472), AtMPK8 (BAA92222), ZmMPK6 (AY425817).