Abstract:Abstract: To reveal the function and expression patterns of CmCAD genes in ‘Sanhongmiyou’ pummelo fruit during its fruit development stages. Three CmCAD genes named CmCAD1, CmCAD3 and CmCAD4 were cloned by reverse transcription PCR, proteins encoded by these genes were analyzed by series of bioinformatic methods, the expression patterns of CmCAD genes in ‘Sanhongmiyou’ pummelo and its bud mutation varieties at different development stages were analyzed either. The results showed that the cDNA length of three CmCAD genes were 1 032 bp, 1 080 bp and 1 071 bp respectively, encoding 344, 360 and 357 amino acids. Bioinformatic analysis showed that proteins encoded by three CmCAD genes contained same conserved domain, all of them had transmembrane spiral structure and phosphorylation sites. Phylogenetic analysis revealed that CmCAD1, CmCAD3 and CmCAD4 were closely related to Citrus sinensis CsCAD1, Arabidopsis thaliana AtCAD9 and Citrus sinensis CsPAL4 respectively. The results of real-time quantitative PCR showed that the expression levels of CmCAD gene members in different varieties pummelo had significant differences at fruit development stages. Meanwhile, during ‘Sanhongmiyou’ fruit development stages, the expression patterns of CmCAD gene members were different either. We speculated that CmCAD4 gene has some potential functions and might involved the regulation of lignin synthesis in ‘Sanhongmiyou’ fruit, but the specific function and regulatory mechanism of the gene need to be further explored.