Sequence analysis of GhMPK16. (A) Alignment of the deduced GhMPK16 protein sequence with other known plant group D MAPKs. Amino acid sequences used in the analysis are from Arabidopsis thaliana (AtMPK16, NP_197402), Triticum aestivum (TaMAPK2, ABC54585), Zea mays (ZmMPK6, NP_001105238), Oryza sativa (OsMPK16-1, ACF06191), Gossypium hirsutum (GhMPK16, FJ966888). These sequences were aligned using the DNAman 6.0 program. Identical and similar amino acids were shaded in black and gray, respectively. The protein kinase subdomains are indicated by Roman numerals (I to XI) over the sequences. The activation-loop is boxed, and the phosphorylation motif (TDY) is marked by an arrow. (B) The phylogenetic relationships of GhMPK16 and other plant MAPKs. Numbers above or below the branches indicate bootstrap values (>50%) from 1,000 replicates. The amino acid sequences of MAPKs used for construction of the tree are deposited to the GenBank database under the following accession numbers: AtMPK3 (NP_190150); NtWIPK (BAA09600); PsMAPK3 (AAF73236); OsMPK5 (AAL87689); AtMPK6 (NP_181907); NtSIPK (AAB58396); NtNTF6 (CAA58760); AtMPK5 (NP_567378); AtMPK4 (NP_192046); OsMPK6 (NP_922504); AtMPK7 (NP_179409); OsMPK3 (ABH01189); NtNTF3 (CAA49592); AtMPK1 (NP_172492); GhMAPK (ABA00652); AtMPK18 (NP_175756); OsMPK8 (CAD54742); AtMPK17 (NP_001030941); AtMPK15 (NP_565070); AtMPK9 (NP_566595); OsMPK12 (AAD52659); AtMPK16 (NP_197402); GhMPK16 (FJ966889); OsMPK15 (ACD76441); ZmMPK6 (NP_001105238); OsMPK16-1 (ACF06191); TaMAPK2 (ABC54585). At, Arabidopsis thaliana; Nt, Nicotiana tobacum; Ps, Pisum sativum; Ta, Triticum aestivum; Zm, Zea mays; Os, Oryza sativa; Gh, Gossypium hirsutum. The Ser/Thr kinase domain is indicated as gray and contains part of the activation-loop motif; the CD domain required for MAPK docking is indicated in black. GhMPK16 is boxed in the diagram and classified as a member of the TDY group.