Viroids; Plant-interaction; gene silencing; Protein interaction; peach tree disease
Abstract :
[en] Viroids are non encapsidated small RNA plant pathogens unable to produce any protein. They are able to infect dramatically a broad range of plants including herbaceous and tree crops. The ways by which viroids are able to induce diseases are actually unknown. However, recent studies have shown that viroids are able to regulate the gene expression of their hosts, they can modify the host-protein phosphorylation sensibility and they interact with host-protein implicated RNA trafficking and protein phosphorylation. Moreover during their evolution plants have developed a mechanism able to regulate their gene expression and to degrade exogenous RNAs like viroids: the gene silencing. Unfortunately, this pathway seems, now, also highly implicated in the symptoms development. This review describes studies that are realized since a few years to increase the knowledge about the plant-viroid relationship. [fr] Les viroïdes sont des petits ARNs pathogènes de nombreuses cultures herbacées ou ligneuses non encapsidés et ne codant pour aucune protéine. La façon dont les viroïdes induisent des maladies est encore très peu connue. Cependant, des études récentes ont montré que les viroïdes étaient capables de modifier l’expression des gènes de leur plante hôte, de modifier la sensibilité de certaines protéines à la phosphorylation, d’interagir avec des protéines de l’hôte impliquées dans le mouvement des ARN et dans la phosphorylation des protéines. De plus, les végétaux possèdent un mécanisme de défense vis-à-vis d’ARN exogène : l’extinction de gène. Ce mécanisme, stimulé lors d’infections viroïdales, est en outre capable de réguler l’expression des gènes endogènes et serait impliqué dans l’expression des symptômes dus aux viroïdes. Depuis quelques années, des études sont réalisées afin de comprendre les relations hôte-pathogène s’établissant entre les viroïdes et leurs hôtes.
Angell S.M. & Baulcombe B., 1997. Consistent gene silencing in transgenic plants expressing a replicating potato virus X RNA. EMBO J., 16(12), 3675-3684.
Baulcombe D.C., 1996. RNA as a target and an initiator of post-transcriptional gene silencing in transgenic plants. Plant Mol. Biol., 32, 79-88.
Bussière F., Lafontaine D. & Perreault J.P., 1996. Compilation and analysis of viroid and viroid-likeRNA sequences. Nucleic Acids Res., 24(10), 1793-1798.
Daros J.A., Elena S.F. & Flores R., 2006. Viroids: an Ariadne's thread into the RNA labyrinth. EMBO J., 7(6), 593-598.
De La Pena M., Navarro B. & Flores R., 1999. Mapping the molecular determinant of pathogenicity in a hammerhead viroid: a tetraloop within the in vivo branched RNA conformation. Proc. Natl Acad. Sci. USA, 96(17), 9960-9965.
De la Pena M. & Flores R., 2002. Chrysanthemum Chlorotic Mottle Viroid RNA: dissection of the pathogenicity determinant and comparative fitness of symptomatic and non-symptomatic variants. J. Mol. Biol., 321, 411-421.
Diener T.O, 1971. Potato spindle tuber "virus". IV. A replicating, low molecular weight RNA. Virology, 45(2), 411-428.
Diener T.O., Hammond R.W., Black T. & Katze M.G., 1993. Mechanism of viroid pathogenesis: differential activation of the interferon-induced, double-stranded RNA-activated, M(r) 68,000 protein kinase by viroid strains of varying pathogenicity. Biochimie, 75, 533-538.
Dillin A, 2003. The specifics of small interfering RNA specificity. Proc. Natl Acad. Sci. USA, 100(11), 6289-6291.
Ding B., 2009. The biology of viroid-host interactions. Annu. Rev. Phytopathol., 47, 105-131.
Ding S. et al., 2004. RNA silencing: a conserved antiviral immunity of plants and animals. Virus Res., 102(1), 109-115.
Ding B. & Itaya A., 2007. Viroid: a useful model for studying the basic principles of infection and RNA biology. Mol. Plant-Microbe Interact., 20(1), 7-20.
Flores R., Randless J.W., Bar-Joseph M. & Diener T.O., 2000. Subviral agents: viroids. In: van Regenmortel M.H.V. et al. Virus Taxonomy. 7th report of the International Committee on Taxonomy of Viruses. San Diego, CA, USA: Academic Press, 1009-1024.
Flores R. et al., 2004. Viroids: the minimal non-coding RNAs with autonomous replication. FEBS Lett., 567, 42-48.
Gomez G. & Pallas V., 2004. A long-distance translocatable phloem protein from cucumber forms a ribonucleoprotein complex in vivo with hop stunt viroid RNA. J. Virol., 78(10), 10104-10110.
Gomez G., Martinez G. & Pallas V., 2008. Viroid-induced symptoms in Nicotinia Benthamiana plants are dependent on RDR6 activity. Plant Physiol., 148, 414-423.
Gora-Sochacka A., 2004. Viroids: unusual small pathogenic RNAs. Acta Biochim. Pol., 51(3), 587-607.
Hamilton A.J. & Baulcombe D.C., 1999. A species of small antisense RNA in posttranscriptional gene silencing in plants. Science, 286, 950-952.
Hammond R.W. & Zhao Y., 2000. Characterization of a tomato protein kinase gene induced by infection by Potato spindle tuber viroid. Mol. Plant-Microbe Interact., 13(9), 903-910.
Hiddinga H.J., Crum C.J., Hu J. & Roth D.A., 1988. Viroidinduced phosphorylation of a host protein related to a dsRNA-dependent protein kinase. Science, 241, 451-453.
Itaya A. et al., 2002. Potato spindle tuber viroid strains of different pathogenicity induces and suppresses expression of common and unique genes in infected tomato. Mol. Plant-Microbe Interact., 15(10), 990-999.
Jana S., Chakraborty C. & Nandi S., 2004. Mechanisms and roles of the RNA-based gene silencing. Electron. J. Biotechnol., 7(3), 324-335.
Keese P. & Symons R.H., 1985. Domains in viroids: evidence of intermolecular RNA rearrangements and their contribution to viroid evolution. Proc. Natl Acad. Sci. USA, 82(14), 4582-4586.
Landry P., Thompson D. & Perreault J., 2004. The role of viroids in gene silencing: the model case of Peach Latent Mosaic viroid. Can. J. Plant Pathol., 26, 1-8.
Langland J.O., Jin S., Jacobs B.L. & Roth D.A., 1995. Identification of a plant-encoded analog of PKR, the mammalian double stranded RNA-dependent protein kinase. Plant Physiol., 108, 1259-1267.
Li W.X. & Ding S.H., 2001. Viral suppressor of RNA silencing. Curr. Opin. Biotechnol., 12, 150-154.
Malfitano M. et al., 2003. Peach Latent Mosaic Viroid variants inducing peach calico (extreme chlorosis) contain a characteristic insertion that is responsible for this symptomatology. Virology, 313, 492-501.
Martinez de Alba A.E., Sägesser R., Tabler M. & Tsagris M., 2003. A bromodomain-containing protein from tomato specifically binds Potato Spindle Tuber Viroid RNA in vitro and in vivo. J. Virol., 77(17), 9685-9694.
Papaefthimiou I. et al., 2001. Replicating potato spindle tuber viroid RNA is accompagnied by short RNA fragments that are characteristic of post-transcriptional gene silencing. Nucleic Acids Res., 29(11), 2395-2400.
Qi Y. & Ding B., 2003. Inhibition of cell growth and shoot development by a specific nucleotide sequence in a noncoding viroid RNA. Plant Cell, 15, 1360-1374.
Rodio M.E., Delgado S., Flores R. & Di Serio F., 2006. Variants of peach latent mosaic viroid inducing peach calico: uneven distribution in infected plant and requirements of the insertion containing the pathogenicity determinant. J. Virol., 87, 231-240.
Rodio M.E. et al., 2007. A viroid RNA with specific structural motif inhibits chloroplast development. Plant Cell, 19, 3610-3626.
Tessitori M. et al., 2007. Differential display analysis of gene expression in Ertog citron leaves infected by Citrus Viroid III. Biochim. Biophys. Acta, 1769, 228-235.
Vera P. & Conejero V., 1990. Citrus Exocortis Viroid infection alters the in vitro pattern of protein phosphorylation of tomato leaf proteins. Mol. Plant-Microbe Interact., 3(1), 28-32.
Wang M. et al., 2004. On the role of RNA silencing in the pathogenicity and evolution of viroids and viral satellites. Proc. Natl Acad. Sci. USA, 101(9), 3275-3280.
