Molecular Cloning and Sequence Analysis of PR2-Like Sequences in Oryza alta

Two sets of degenerate primers,which were designed based on the conservative domain of known plant pathogenesis-related protein gene β-1,3-glucanase,were used to isolated defense-genes analogues(DGAs) from genomic DNA of the Oryza alta.The desired bands were purified from the gel,and then cloned by T/A cloning.After sequencing and analyzing by alignment,three DGAs with uninterrupted open reading frames(ORFs) were obtained,except for one with immature stop codon.At the nucleic acid level,sequence identity of three DGAs with the β-1,3-glucanase genes of Oryza sativa ranged from 90% to 93%,and with the β-1,3-glucanase genes from Hordeum vulgare,Triticum aestivum,Sorghum bicolor,Secale cereale,Avena sativa and Zea mays ranged from 69% to 81%.At the amino acid level,the results showed that both two DGAs RD1-GG6 and RD1-GG12 were highly homologous with β-1,3-glucanase amino acid sequences of Oryza sativa,Hordeum vulgare,Triticum aestivum,Secale cereale with 60%-93%.More importantly,expression level of RD1-GG6 and RD1-GG12 were upregulated at 3,12,24 and 48 h after salicylic acid(SA) treatment.