title: Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes.
abstract: Plant genomes contain several hundred defensin-like (DEFL) genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species.
authors.affiliation: Department of Plant Biology, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: Mesfin
authors.initials: M
authors.lastname: Tesfaye
authors.forename: Kevin At
authors.initials: KA
authors.lastname: Silverstein
authors.forename: Sumitha
authors.initials: S
authors.lastname: Nallu
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Botanga
authors.forename: S Karen
authors.initials: SK
authors.lastname: Gomez
authors.forename: Liliana M
authors.initials: LM
authors.lastname: Costa
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Harrison
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Samac
authors.forename: Jane
authors.initials: J
authors.lastname: Glazebrook
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Katagiri
authors.forename: Jose F
authors.initials: JF
authors.lastname: Gutierrez-Marcos
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Vandenbosch
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology; D016000:Cluster Analysis; D023082:Defensins / Q000235:genetics*; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics; D046913:Medicago truncatula / Q000235:genetics*; D009928:Organ Specificity / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified; D015203:Reproducibility of Results; D036226:Seedlings / Q000235:genetics; D015398:Signal Transduction; D013559:Symbiosis / Q000235:genetics
chemical_list: D023082:Defensins