Abstract: Agene encoding a Slike RNase (CgSL1) was isolated from the styles of two self incompatible pomelo cultivars Citrus grandis Osbeck vs.Guanxi and vs.Duwei.The cDNAof CgSL1 was 1074 bp in length with a capability of encoding a polypeptide consisting of 297 amino acids.Sequence comparison showed that CgSL1 was more similar to S-like RNases than to S RNases and had a highest similarity with 62.5% identity to RNS2 from Arabidopsis thaliana.To reveal the tissue specificity and the temporal expression patterns of CgSL1,RT-PCR was conducted with RNAs from several tissues.Results showed that CgSL1 expressed in styles,anthers and leaves,and its expression in styles increased in the proceeding of style senescence,suggesting that CgSL1 may be related to senescence.