title: Differential display analysis of gene expression in Etrog citron leaves infected by Citrus viroid III.
abstract: Citrus are natural hosts of several viroids, which are plant pathogens composed exclusively of a non-protein-coding, small single-stranded circular RNA that is able to replicate autonomously in susceptible hosts. They are responsible for symptoms such as stunting, leaf epinasty, and chlorosis. Citrus viroid III (CVd-III) has been long regarded as a possible dwarfing agent of citrus grafted on trifoliate orange and its hybrids. To investigate molecular mechanisms involved in pathogenesis, the messenger RNA (mRNA) differential display technique was here applied to identify genes whose transcription was significantly altered in leaves of Etrog citron (Citrus medica) infected by CVd-III (variant b). Of eighteen genes identified, thirteen were up-regulated by viroid infection, while five were down-regulated. Except for two genes that encode proteins of unknown function, the remaining genes are mainly involved in plant defence/stress responses, signal transduction, amino acid transport, and cell wall structure. Among the up-regulated genes, it is noteworthy a suppressor of RNA silencing that might be involved in viroid and virus pathogenicity. The functions of these genes are discussed.
authors.affiliation: Dipartimento di Scienze e Tecnologie Fitosanitarie, DISTEF, University of Catania, Italy.
authors.forename: Matilde
authors.initials: M
authors.lastname: Tessitori
authors.forename: Giovanna
authors.initials: G
authors.lastname: Maria
authors.forename: Clemente
authors.initials: C
authors.lastname: Capasso
authors.forename: Giuliana
authors.initials: G
authors.lastname: Catara
authors.forename: Serena
authors.initials: S
authors.lastname: Rizza
authors.forename: Viviana
authors.initials: V
authors.lastname: De Luca
authors.forename: Antonino
authors.initials: A
authors.lastname: Catara
authors.forename: Antonio
authors.initials: A
authors.lastname: Capasso
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Carginale
mesh_terms: D002957:Citrus / Q000235:genetics* / Q000821:virology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000821:virology; D018515:Plant Leaves / Q000235:genetics / Q000821:virology; D010942:Plant Viruses / Q000472:pathogenicity; D018749:RNA, Plant / Q000032:analysis; D015398:Signal Transduction / Q000235:genetics; D014772:Viroids / Q000472:pathogenicity
chemical_list: D018749:RNA, Plant