The availability of sorghum genome makes it possible to perform the genomewide analysis of the expression profile of MAPKs genes in Sorghum bicolor under the stresses of NaCl and Na2CO3 so as to explore the MAPKs involvement into salinealkali signaling pathway. The results show that 16 MAPKs genes were dentified from the genome of Sorghum bicolor, namely SbMPKs, and their expression profiles under the stresses of NaCl and Na2CO3 differ from each other significantly. This suggests that neutral saltinduced signal response may differ from that induced by alkaline salt. Under the stress of NaCl, all SbMPKs were upregulated continuously during 24 h except the SbMPK13 whose expression reached to the maximum at 12 h. Under the stress of Na2CO3, however, only SbMPK3,SbMPK10 and SbMPK13 were upregulated, implying that SbMPKs are likely responsible specifically for alkaline salt stress in sorghum. P
hylogenetic analysis classified SbMPK13 into the C group of MAPKs, which is similar toOsMAPK2 that is responsible to ABA and salt stress in rice, further confirming that it is involved possibly in the regulation of salt stress response genes in sorghum.