Cloning, characterization and promoter analysis of S-RNase gene promoter from Chinese pear (Pyrus pyrifolia)

The 5′‐flanking region of the S12-, S13-, S21-RNase with a length of 854 bp, 1448 bp and 1137 bp were successfully isolated by TAIL-PCR from genomic DNA from ‘Jinhua’, ‘Maogong’ (Pyrus pyrifolia) and ‘Yali’ (Pyrus bretschneideri) genomic DNA. Sequence alignment and analysis of S13-, S12-, S21-RNase gene promoter sequences with S2-, S3-, S4-, S5-RNase 5′-flanking sequences indicated that a homology region of about 240 bp exists in the regions just upstream of the putative TATA boxes of the seven Chinese/Japanese pear S-RNase genes. Phylogenetic tree suggests that the homology region between the Chinese/Japanese pear and apple S-RNase gene promoter regions reflects the divergence of S-RNase gene was formed before the differentiation of subfamilies. Full length and a series of 5′-deletion fragments-GUS fusions were constructed and introduced into Arabidopsis thaliana plants. GUS activity were detected in S12-pro-(1 to 5)-GUS‐pBll01.2 transgenic pistils and progressively decreased from S12-pro-1-GUS-pBI l01.2 to S12-pro-5-GUS-pBll01.2. No GUS activity was detected in S12-pro-6-GUS-pBll01.2 transgenic pistil and other tissues of non-transformants and all transgenic plants. The result suggested S12-RNase promoter is pistil specific expression promoter.

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► The 5′‐flanking region of the S12-, S13-, S21-RNase was isolated from Chinese pear.
► A 240 bp homology region was found in these Chinese/Japanese pear S-RNase genes.
► GUS activity was detected progressively decreased only in the transgenic pistils.
► S12-RNase promoter is pistil specific expression promoter by GUS dying.