A novel MAP kinase gene in cotton (Gossypium hirsutum L.), GhMAPK, is involved in response to diverse environmental stresses.

The mitogen-activated protein kinase (MAPK) cascade is one of the major and evolutionally conserved signaling pathways and plays pivotal role in the regulation of stress and developmental signals in plants. Here, a novel gene, termed Gossypium hirsutum MAPK (GhMAPK), was isolated from cotton. The full-length cDNA of GhMAPK encodes for a 372 amino acid protein that contains all 11 of the MAPK conserved subdomains and the phosphorylation-activation motif, TEY. Amino acid sequence alignment revealed that GhMAPK shared high identity with group-C MAPK in plants and showed 83 approximately 89% similarities with MAPKs from Arabidopsis, apricot, pea, petunia, and tobacco. Southern blot analysis indicated that the GhMAPK belonged to a multygene family in cotton. Two introns were found within the region of genomic sequence. Northern blot analysis revealed that the transcripts of GhMAPK accumulated markedly when the cotton seedlings were subjected to various abiotic stimuli such as wounding, cold (4 degrees C), or salinity stress; Furthermore, GhMAPK was upregulated by the exogenous signaling molecules, such as salicylic acid (SA) and hydrogen peroxide (H(2)O(2)), as well as pathogen attacks. These results indicate that the GhMAPK, which has a high degree of identity with group-C plant MAPKs, may also play an important role in response to environmental stresses.