title: Genome-wide identification and expression analysis of the polyamine oxidase gene family in sweet orange (Citrus sinensis).
abstract: Polyamine oxidases (PAOs) are FAD-dependent enzymes associated with polyamine catabolism. In plants, increasing evidences support that PAO genes play essential roles in abiotic and biotic stresses response. In this study, six putative PAO genes (CsPAO1-CsPAO6) were unraveled in sweet orange (Citrus sinensis) using the released citrus genome sequences. A total of 203 putative cis-regulatory elements involved in hormone and stress response were predicted in 1.5-kb promoter regions at the upstream of CsPAOs. The CsPAOs can be divided into four major groups, with similar organizations with their counterparts of Arabidopsis thaliana. Transcripts of CsPAOs were detected in leaf, stem, cotyledon, and root, with the highest levels detected in the roots. The CsPAOs displayed various responses to exogenous treatments with polyamines and ABA and were differentially altered by abiotic stresses, including cold, salt, and mannitol. Overexpression of CsPAO3 in tobacco demonstrated that spermidine and spermine were decreased in the transgenic line, while putrescine was significantly enhanced, implying a potential role of this gene in polyamine back conversion. These data provide valuable knowledge for understanding the roles of the PAO genes in the future.
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: liujihong@mail.hzau.edu.cn.
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D032084:Citrus sinensis / Q000201:enzymology / Q000235:genetics*; D018548:Cotyledon / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D056726:Genetic Association Studies; D014644:Genetic Variation; D008969:Molecular Sequence Data; D005810:Multigene Family; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018547:Plant Stems / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid; D000097667:Polyamine Oxidase
chemical_list: D000587:Oxidoreductases Acting on CH-NH Group Donors; D011073:Polyamines; D000097667:Polyamine Oxidase
keywords: Abiotic stress; Citrus sinensis; Gene expression; Polyamine catabolism; Polyamine oxidase