According to the sequences of GenBank and relative references, a fragment of 930 bp including the total open reading frame of Ospgip1 gene was amplified. Prokaryotic expression product of the gene could inhibit the growth and polygalacturonase (PG) activity of Rhizoctonia solani, the pathogen of rice sheath blight. Bioinformatics analysis showed that OsPGIP1 was a hydrophobic protein with a molecular weight of 32.8 kDa and a pI of 7.26. The protein was mainly located in the cell wall of rice, and the splice site of its signal peptide was between the 17th and 18th amino acid residue. There were four cysteines in the N- and C-terminal of the deduced amino acid sequence, respectively, forming three disulfide bonds (Between 56th and 63rd, 278th and 298th, 300th and 308th amino acid residue, respectively). The main structural elements of the deduced protein, which showed the typical leucine-rich repeat(LRR) modular organization, were α-helix, β-sheet and irregular circle. Comparing to PGIPs of other plants, the 7th LRR of this protein was absent. The nine LRRs could form a cleft which would be the activity site domain between the protein-protein interaction of the PGIP from rice and PG from the pathogenic fungi.
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