Prokaryotic expression and polyclonal antibody preparation of the extracellular domain about rice LRR receptor-like protein kinase

Previous study indicated that the expression of a LRR receptor-like protein kinase OsRLK in root tips of rice could be induced by salt stress. In order to study the functions of OsRLK, the extracellular fragment of OsRLK gene was obtained through RT-PCR. The target fragment was subcloned into pET29a, and the recombinant plasmid pET29a-RLK was transformed into E. coli BL21 (DE3). The target fragment over-expressed in host strain, and the expression level was about 30% of the total cellular protein. After separated by SDS-PAGE, the target band was excised from the gel, and was used as an antigen to raise the antibody in New Zealand rabbits. After separation and purification of antiserum, the anti-OsRLK polyclonal antibody with the titers of I : 20 000 was successfully prepared. Western blot analysis showed that the antibody could specifically recognize the expressed fragment in E. colt and the OsRLK protein in root tips from rice. In addition, for the first time, the OsRLK was confirmed as a salt stress responsive protein.