Stress induced MAPK genes show distinct pattern of codon usage in Arabidopsis thaliana,Glycine max and Oryza sativa

Mitogen activated protein kinase (MAPK) genes provide resistance to various biotic and abiotic stresses. Codon usage profiling ofthe genes reveals the characteristic features of the genes like nucleotide composition, gene expressivity, optimal codons etc. Thepresent study is a comparative analysis of codon usage patterns for different MAPK genes in three organisms, viz. Arabidopsisthaliana, Glycine max (soybean) and Oryza sativa (rice). The study has revealed a high AT content in MAPK genes of Arabidopsis andsoybean whereas in rice a balanced AT-GC content at the third synonymous position of codon. The genes show a low bias in codonusage profile as reflected in the higher values (50.83 to 56.55) of effective number of codons (N_c). The prediction of gene expressionprofile in the MAPK genes revealed that these genes might be under the selective pressure of translational optimization as reflectedin the low codon adaptation index (CAI) values ranging from 0.147 to 0.208.