title: WRKY domain-encoding genes of a crop legume chickpea (Cicer arietinum): comparative analysis with Medicago truncatula WRKY family and characterization of group-III gene(s).
abstract: The WRKY genes have been identified as important transcriptional modulators predominantly during the environmental stresses, but they also play critical role at various stages of plant life cycle. We report the identification of WRKY domain (WD)-encoding genes from galegoid clade legumes chickpea (Cicer arietinum L.) and barrel medic (Medicago truncatula). In total, 78 and 98 WD-encoding genes were found in chickpea and barrel medic, respectively. Comparative analysis suggests the presence of both conserved and unique WRKYs, and expansion of WRKY family in M. truncatula primarily by tandem duplication. Exclusively found in galegoid legumes, CaWRKY16 and its orthologues encode for a novel protein having a transmembrane and partial Exo70 domains flanking a group-III WD. Genomic region of galegoids, having CaWRKY16, is more dynamic when compared with millettioids. In onion cells, fused CaWRKY16-EYFP showed punctate fluorescent signals in cytoplasm. The chickpea WRKY group-III genes were further characterized for their transcript level modulation during pathogenic stress and treatments of abscisic acid, jasmonic acid, and salicylic acid (SA) by real-time PCR. Differential regulation of genes was observed during Ascochyta rabiei infection and SA treatment. Characterization of A. rabiei and SA inducible gene CaWRKY50 showed that it localizes to plant nucleus, binds to W-box, and have a C-terminal transactivation domain. Overexpression of CaWRKY50 in tobacco plants resulted in early flowering and senescence. The in-depth comparative account presented here for two legume WRKY genes will be of great utility in hastening functional characterization of crop legume WRKYs and will also help in characterization of Exo70Js.
authors.affiliation: Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Kamal
authors.initials: K
authors.lastname: Kumar
authors.affiliation: Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Srivastava
authors.affiliation: Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Savithri
authors.initials: S
authors.lastname: Purayannur
authors.affiliation: School of Life Sciences, Central University of Gujarat, Gandhinagar 382030, Gujarat, India.
authors.forename: V Chandra
authors.initials: VC
authors.lastname: Kaladhar
authors.affiliation: Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Purnima Jaiswal
authors.initials: PJ
authors.lastname: Cheruvu
authors.affiliation: Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India pkv@nipgr.ac.in.
authors.forename: Praveen Kumar
authors.initials: PK
authors.lastname: Verma
mesh_terms: D029863:Cicer / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D046913:Medicago truncatula / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D000072417:Protein Domains; D020156:Salicylic Acid / Q000494:pharmacology; D016415:Sequence Alignment; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D020156:Salicylic Acid
keywords: Ascochyta rabiei; Exo70; WRKY domain