title: The WRKY Transcription Factor Family in Citrus: Valuable and Useful Candidate Genes for Citrus Breeding.
abstract: WRKY transcription factors belong to a large family of plant transcriptional regulators whose members have been reported to be involved in a wide range of biological roles including plant development, adaptation to environmental constraints and response to several diseases. However, little or poor information is available about WRKY's in Citrus. The recent release of completely assembled genomes sequences of Citrus sinensis and Citrus clementina and the availability of ESTs sequences from other citrus species allowed us to perform a genome survey for Citrus WRKY proteins. In the present study, we identified 100 WRKY members from C. sinensis (51), C. clementina (48) and Citrus unshiu (1), and analyzed their chromosomal distribution, gene structure, gene duplication, syntenic relation and phylogenetic analysis. A phylogenetic tree of 100 Citrus WRKY sequences with their orthologs from Arabidopsis has distinguished seven groups. The CsWRKY genes were distributed across all ten sweet orange chromosomes. A comprehensive approach and an integrative analysis of Citrus WRKY gene expression revealed variable profiles of expression within tissues and stress conditions indicating functional diversification. Thus, candidate Citrus WRKY genes have been proposed as potentially involved in fruit acidification, essential oil biosynthesis and abiotic/biotic stress tolerance. Our results provided essential prerequisites for further WRKY genes cloning and functional analysis with an aim of citrus crop improvement.
authors.affiliation: Laboratory of Extremophile Plants. Center of Biotechnology of Borj-Cédria (CBBC), BP 901, Hammam-lif, 2050, Tunisia. mariem.ayedi@gmail.com.|Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Sidi Mansour Road, P.O. Box 1177, 3018, Sfax, Tunisia. mariem.ayedi@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Ayadi
authors.affiliation: Laboratory of Extremophile Plants. Center of Biotechnology of Borj-Cédria (CBBC), BP 901, Hammam-lif, 2050, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Hanana
authors.affiliation: Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Sidi Mansour Road, P.O. Box 1177, 3018, Sfax, Tunisia.
authors.forename: N
authors.initials: N
authors.lastname: Kharrat
authors.affiliation: Laboratory of Extremophile Plants. Center of Biotechnology of Borj-Cédria (CBBC), BP 901, Hammam-lif, 2050, Tunisia.
authors.forename: H
authors.initials: H
authors.lastname: Merchaoui
authors.affiliation: Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Sidi Mansour Road, P.O. Box 1177, 3018, Sfax, Tunisia.
authors.forename: R Ben
authors.initials: RB
authors.lastname: Marzoug
authors.affiliation: Unit 'Ecophysiology and Grape Functional Genomics' Institute of Vine and Wine Sciences, INRA Bordeaux-Aquitaine, 210 Chemin de Leysotte - CS 50008, 33882, Villenave d'Ornon Cedex, France.
authors.forename: V
authors.initials: V
authors.lastname: Lauvergeat
authors.affiliation: Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Sidi Mansour Road, P.O. Box 1177, 3018, Sfax, Tunisia.
authors.forename: A
authors.initials: A
authors.lastname: Rebaï
authors.affiliation: Laboratory of Extremophile Plants. Center of Biotechnology of Borj-Cédria (CBBC), BP 901, Hammam-lif, 2050, Tunisia.
authors.forename: R
authors.initials: R
authors.lastname: Mzid
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D032461:Chromosomes, Plant / Q000235:genetics; D002957:Citrus / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D016000:Cluster Analysis; D003198:Computer Simulation; D017124:Conserved Sequence; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D056726:Genetic Association Studies; D005810:Multigene Family; D010802:Phylogeny; D000069600:Plant Breeding; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000072417:Protein Domains; D016415:Sequence Alignment; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D026801:Synteny / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Citrus; Essential oil biosynthesis; Fruit acidification; Stress tolerance; WRKY; Zinc finger