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Genetic and histological studies on the delayed systemic movement of Tobacco Mosaic Virus in Arabidopsis thaliana.

Serrano C, González-Cruz J, Jauregui F, Medina C, Mancilla P, Matus JT, Arce-Johnson P - BMC Genet. (2008)

Bottom Line: Electron microscopy studies following the virion's route in stems of Col-0 infected plants showed the presence of curved structures, instead of the typical rigid rods of TMV-U1.This was not observed in the case of TMV-U1 infection in Uk-4, where the observed virions have the typical rigid rod morphology.The presence of defectively assembled virions observed by electron microscopy in vascular tissue of Col-0 infected plants correlates with a recessive delayed systemic movement trait of TMV-U1 in this ecotype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Casilla 114-D. Santiago, Chile. clserran@puc.cl

ABSTRACT

Background: Viral infections and their spread throughout a plant require numerous interactions between the host and the virus. While new functions of viral proteins involved in these processes have been revealed, current knowledge of host factors involved in the spread of a viral infection is still insufficient. In Arabidopsis thaliana, different ecotypes present varying susceptibilities to Tobacco mosaic virus strain U1 (TMV-U1). The rate of TMV-U1 systemic movement is delayed in ecotype Col-0 when compared with other 13 ecotypes.We followed viral movement through vascular tissue in Col-0 plants by electronic microscopy studies. In addition, the delay in systemic movement of TMV-U1 was genetically studied.

Results: TMV-U1 reaches apical leaves only after 18 days post rosette inoculation (dpi) in Col-0, whereas it is detected at 9 dpi in the Uk-4 ecotype. Genetic crosses between Col-0 and Uk-4 ecotypes, followed by analysis of viral movement in F1 and F2 populations, revealed that this delayed movement correlates with a recessive, monogenic and nuclear locus. The use of selected polymorphic markers showed that this locus, denoted DSTM1 (Delayed Systemic Tobamovirus Movement 1), is positioned on the large arm of chromosome II. Electron microscopy studies following the virion's route in stems of Col-0 infected plants showed the presence of curved structures, instead of the typical rigid rods of TMV-U1. This was not observed in the case of TMV-U1 infection in Uk-4, where the observed virions have the typical rigid rod morphology.

Conclusion: The presence of defectively assembled virions observed by electron microscopy in vascular tissue of Col-0 infected plants correlates with a recessive delayed systemic movement trait of TMV-U1 in this ecotype.

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Differential systemic movement of TMV-U1 in two Arabidopsis thaliana ecotypes. Col-0 and Uk-4 plants were mechanically inoculated on three rosette leaves with a solution of 10 ng/μl of virus diluted in 20 mM phosphate buffer. (a) In situ hybridisation of inoculated and apical leaves from infected plants at 10 dpi. Leaves were incubated with a TMV-U1 coat protein DNA probe. The virus coat protein gene was detected ubiquitously in inoculated leaves from both ecotypes, but only in an apical leaf of Uk-4 plants. Images represent equivalent levels of exposure to film. (b) Western blot showing similar time-courses of TMV-U1 infection in inoculated leaves of Col-0 (upper) and Uk-4 (bottom) plants. Coat protein is evident in both cases starting from 4 dpi. (c) ELISA showing differences in the systemic spread of TMV-U1 in Col-0 and Uk-4 plants. Apical leaves of inoculated plants were analysed for 18 dpi.
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Figure 1: Differential systemic movement of TMV-U1 in two Arabidopsis thaliana ecotypes. Col-0 and Uk-4 plants were mechanically inoculated on three rosette leaves with a solution of 10 ng/μl of virus diluted in 20 mM phosphate buffer. (a) In situ hybridisation of inoculated and apical leaves from infected plants at 10 dpi. Leaves were incubated with a TMV-U1 coat protein DNA probe. The virus coat protein gene was detected ubiquitously in inoculated leaves from both ecotypes, but only in an apical leaf of Uk-4 plants. Images represent equivalent levels of exposure to film. (b) Western blot showing similar time-courses of TMV-U1 infection in inoculated leaves of Col-0 (upper) and Uk-4 (bottom) plants. Coat protein is evident in both cases starting from 4 dpi. (c) ELISA showing differences in the systemic spread of TMV-U1 in Col-0 and Uk-4 plants. Apical leaves of inoculated plants were analysed for 18 dpi.

Mentions: In situ hybridization was used to compare virus accumulation in inoculated and systemic leaves of Arabidopsis ecotypes Uk-4 and Col-0. As expected, viral RNA was present in apical leaves of Uk-4 at 10 dpi, but not in those from the Col-0 ecotype (Figure 1a) even when inoculated leaves of both ecotypes were completely infected at this time point (Figure 1a). This result confirms the Uk-4 and Col-0 differences in viral systemic movement as was previously described by Arce-Johnson et al. 2000 [16].


Genetic and histological studies on the delayed systemic movement of Tobacco Mosaic Virus in Arabidopsis thaliana.

Serrano C, González-Cruz J, Jauregui F, Medina C, Mancilla P, Matus JT, Arce-Johnson P - BMC Genet. (2008)

Differential systemic movement of TMV-U1 in two Arabidopsis thaliana ecotypes. Col-0 and Uk-4 plants were mechanically inoculated on three rosette leaves with a solution of 10 ng/μl of virus diluted in 20 mM phosphate buffer. (a) In situ hybridisation of inoculated and apical leaves from infected plants at 10 dpi. Leaves were incubated with a TMV-U1 coat protein DNA probe. The virus coat protein gene was detected ubiquitously in inoculated leaves from both ecotypes, but only in an apical leaf of Uk-4 plants. Images represent equivalent levels of exposure to film. (b) Western blot showing similar time-courses of TMV-U1 infection in inoculated leaves of Col-0 (upper) and Uk-4 (bottom) plants. Coat protein is evident in both cases starting from 4 dpi. (c) ELISA showing differences in the systemic spread of TMV-U1 in Col-0 and Uk-4 plants. Apical leaves of inoculated plants were analysed for 18 dpi.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2563018&req=5

Figure 1: Differential systemic movement of TMV-U1 in two Arabidopsis thaliana ecotypes. Col-0 and Uk-4 plants were mechanically inoculated on three rosette leaves with a solution of 10 ng/μl of virus diluted in 20 mM phosphate buffer. (a) In situ hybridisation of inoculated and apical leaves from infected plants at 10 dpi. Leaves were incubated with a TMV-U1 coat protein DNA probe. The virus coat protein gene was detected ubiquitously in inoculated leaves from both ecotypes, but only in an apical leaf of Uk-4 plants. Images represent equivalent levels of exposure to film. (b) Western blot showing similar time-courses of TMV-U1 infection in inoculated leaves of Col-0 (upper) and Uk-4 (bottom) plants. Coat protein is evident in both cases starting from 4 dpi. (c) ELISA showing differences in the systemic spread of TMV-U1 in Col-0 and Uk-4 plants. Apical leaves of inoculated plants were analysed for 18 dpi.
Mentions: In situ hybridization was used to compare virus accumulation in inoculated and systemic leaves of Arabidopsis ecotypes Uk-4 and Col-0. As expected, viral RNA was present in apical leaves of Uk-4 at 10 dpi, but not in those from the Col-0 ecotype (Figure 1a) even when inoculated leaves of both ecotypes were completely infected at this time point (Figure 1a). This result confirms the Uk-4 and Col-0 differences in viral systemic movement as was previously described by Arce-Johnson et al. 2000 [16].

Bottom Line: Electron microscopy studies following the virion's route in stems of Col-0 infected plants showed the presence of curved structures, instead of the typical rigid rods of TMV-U1.This was not observed in the case of TMV-U1 infection in Uk-4, where the observed virions have the typical rigid rod morphology.The presence of defectively assembled virions observed by electron microscopy in vascular tissue of Col-0 infected plants correlates with a recessive delayed systemic movement trait of TMV-U1 in this ecotype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Casilla 114-D. Santiago, Chile. clserran@puc.cl

ABSTRACT

Background: Viral infections and their spread throughout a plant require numerous interactions between the host and the virus. While new functions of viral proteins involved in these processes have been revealed, current knowledge of host factors involved in the spread of a viral infection is still insufficient. In Arabidopsis thaliana, different ecotypes present varying susceptibilities to Tobacco mosaic virus strain U1 (TMV-U1). The rate of TMV-U1 systemic movement is delayed in ecotype Col-0 when compared with other 13 ecotypes.We followed viral movement through vascular tissue in Col-0 plants by electronic microscopy studies. In addition, the delay in systemic movement of TMV-U1 was genetically studied.

Results: TMV-U1 reaches apical leaves only after 18 days post rosette inoculation (dpi) in Col-0, whereas it is detected at 9 dpi in the Uk-4 ecotype. Genetic crosses between Col-0 and Uk-4 ecotypes, followed by analysis of viral movement in F1 and F2 populations, revealed that this delayed movement correlates with a recessive, monogenic and nuclear locus. The use of selected polymorphic markers showed that this locus, denoted DSTM1 (Delayed Systemic Tobamovirus Movement 1), is positioned on the large arm of chromosome II. Electron microscopy studies following the virion's route in stems of Col-0 infected plants showed the presence of curved structures, instead of the typical rigid rods of TMV-U1. This was not observed in the case of TMV-U1 infection in Uk-4, where the observed virions have the typical rigid rod morphology.

Conclusion: The presence of defectively assembled virions observed by electron microscopy in vascular tissue of Col-0 infected plants correlates with a recessive delayed systemic movement trait of TMV-U1 in this ecotype.

Show MeSH
Related in: MedlinePlus