Limits...
A multidirectional non-cell autonomous control and a genetic interaction restricting tobacco etch virus susceptibility in Arabidopsis.

Gopalan S - PLoS ONE (2007)

Bottom Line: Molecular genetic analysis and complementation analysis with three alleles of a previously published mutant lsp1 (loss of susceptibility to potyviruses) indicate a genetic interaction conferring haploinsufficiency between the B149 locus and certain alleles of lsp1 resulting in impaired host susceptibility.The pattern of restriction of TEV foci on leaves at or near the boundaries of certain cell types and leaf boundaries suggest dysregulation of a multidirectional non-cell autonomous regulatory mechanism.Understanding the nature of this multidirectional signal and the molecular genetic mechanism conferring it should potentially reveal a novel arsenal in the cellular machinery.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, Washington, United States of America. gopalans2@hotmail.com

ABSTRACT

Background: Viruses constitute a major class of pathogens that infect a variety of hosts. Understanding the intricacies of signaling during host-virus interactions should aid in designing disease prevention strategies and in understanding mechanistic aspects of host and pathogen signaling machinery.

Methodology/principal findings: An Arabidopsis mutant, B149, impaired in susceptibility to Tobacco etch virus (TEV), a positive strand RNA virus of picoRNA family, was identified using a high-throughput genetic screen and a counterselection scheme. The defects include initiation of infection foci, rate of cell-to-cell movement and long distance movement.

Conclusions/significance: The defect in infectivity is conferred by a recessive locus. Molecular genetic analysis and complementation analysis with three alleles of a previously published mutant lsp1 (loss of susceptibility to potyviruses) indicate a genetic interaction conferring haploinsufficiency between the B149 locus and certain alleles of lsp1 resulting in impaired host susceptibility. The pattern of restriction of TEV foci on leaves at or near the boundaries of certain cell types and leaf boundaries suggest dysregulation of a multidirectional non-cell autonomous regulatory mechanism. Understanding the nature of this multidirectional signal and the molecular genetic mechanism conferring it should potentially reveal a novel arsenal in the cellular machinery.

Show MeSH

Related in: MedlinePlus

Dynamics of TEV-GUS infection in C24.Arabidopsis plants (C24 ecotype) were mock inoculated or inoculated with TEV-GUS. Leaves or inflorescence tissue were infiltrated with X-gluc at the time points indicated. Pictures at 1 dpi (Panel A) and 2 dpi (Panel B) are photomicrographs at 200× magnification (with 20× objective and WH10 eyepiece). Panel C is leaves from 3 dpi. In case of 8 dpi (Panel D) and 16 dpi (Panel E), leaves were bleached following color development. Panels F and G are floral clusters from mock inoculated plant and TEV-GUS inoculated plant, respectively (18 dpi).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC1991623&req=5

pone-0000985-g002: Dynamics of TEV-GUS infection in C24.Arabidopsis plants (C24 ecotype) were mock inoculated or inoculated with TEV-GUS. Leaves or inflorescence tissue were infiltrated with X-gluc at the time points indicated. Pictures at 1 dpi (Panel A) and 2 dpi (Panel B) are photomicrographs at 200× magnification (with 20× objective and WH10 eyepiece). Panel C is leaves from 3 dpi. In case of 8 dpi (Panel D) and 16 dpi (Panel E), leaves were bleached following color development. Panels F and G are floral clusters from mock inoculated plant and TEV-GUS inoculated plant, respectively (18 dpi).

Mentions: As previous work in tobacco and Arabidopsis has detailed, infection of TEV typically starts in a single cell and spreads to adjacent cells through plasmodesmata to form visible foci (when stained for GUS activity) in the first two to three days. The foci continue to spread on inoculated leaves and to other parts of the plant. By 10 dpi GUS activity can be detected in the floral tissue, indicative of systemic movement of TEV-GUS. B149 was characterized for susceptibility to TEV-GUS at various stages of infection. The different stages of infection and progression in Arabidopsis is shown in Figure 2 in order to better understand the analyses of each of these steps presented below.


A multidirectional non-cell autonomous control and a genetic interaction restricting tobacco etch virus susceptibility in Arabidopsis.

Gopalan S - PLoS ONE (2007)

Dynamics of TEV-GUS infection in C24.Arabidopsis plants (C24 ecotype) were mock inoculated or inoculated with TEV-GUS. Leaves or inflorescence tissue were infiltrated with X-gluc at the time points indicated. Pictures at 1 dpi (Panel A) and 2 dpi (Panel B) are photomicrographs at 200× magnification (with 20× objective and WH10 eyepiece). Panel C is leaves from 3 dpi. In case of 8 dpi (Panel D) and 16 dpi (Panel E), leaves were bleached following color development. Panels F and G are floral clusters from mock inoculated plant and TEV-GUS inoculated plant, respectively (18 dpi).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1991623&req=5

pone-0000985-g002: Dynamics of TEV-GUS infection in C24.Arabidopsis plants (C24 ecotype) were mock inoculated or inoculated with TEV-GUS. Leaves or inflorescence tissue were infiltrated with X-gluc at the time points indicated. Pictures at 1 dpi (Panel A) and 2 dpi (Panel B) are photomicrographs at 200× magnification (with 20× objective and WH10 eyepiece). Panel C is leaves from 3 dpi. In case of 8 dpi (Panel D) and 16 dpi (Panel E), leaves were bleached following color development. Panels F and G are floral clusters from mock inoculated plant and TEV-GUS inoculated plant, respectively (18 dpi).
Mentions: As previous work in tobacco and Arabidopsis has detailed, infection of TEV typically starts in a single cell and spreads to adjacent cells through plasmodesmata to form visible foci (when stained for GUS activity) in the first two to three days. The foci continue to spread on inoculated leaves and to other parts of the plant. By 10 dpi GUS activity can be detected in the floral tissue, indicative of systemic movement of TEV-GUS. B149 was characterized for susceptibility to TEV-GUS at various stages of infection. The different stages of infection and progression in Arabidopsis is shown in Figure 2 in order to better understand the analyses of each of these steps presented below.

Bottom Line: Molecular genetic analysis and complementation analysis with three alleles of a previously published mutant lsp1 (loss of susceptibility to potyviruses) indicate a genetic interaction conferring haploinsufficiency between the B149 locus and certain alleles of lsp1 resulting in impaired host susceptibility.The pattern of restriction of TEV foci on leaves at or near the boundaries of certain cell types and leaf boundaries suggest dysregulation of a multidirectional non-cell autonomous regulatory mechanism.Understanding the nature of this multidirectional signal and the molecular genetic mechanism conferring it should potentially reveal a novel arsenal in the cellular machinery.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, Washington, United States of America. gopalans2@hotmail.com

ABSTRACT

Background: Viruses constitute a major class of pathogens that infect a variety of hosts. Understanding the intricacies of signaling during host-virus interactions should aid in designing disease prevention strategies and in understanding mechanistic aspects of host and pathogen signaling machinery.

Methodology/principal findings: An Arabidopsis mutant, B149, impaired in susceptibility to Tobacco etch virus (TEV), a positive strand RNA virus of picoRNA family, was identified using a high-throughput genetic screen and a counterselection scheme. The defects include initiation of infection foci, rate of cell-to-cell movement and long distance movement.

Conclusions/significance: The defect in infectivity is conferred by a recessive locus. Molecular genetic analysis and complementation analysis with three alleles of a previously published mutant lsp1 (loss of susceptibility to potyviruses) indicate a genetic interaction conferring haploinsufficiency between the B149 locus and certain alleles of lsp1 resulting in impaired host susceptibility. The pattern of restriction of TEV foci on leaves at or near the boundaries of certain cell types and leaf boundaries suggest dysregulation of a multidirectional non-cell autonomous regulatory mechanism. Understanding the nature of this multidirectional signal and the molecular genetic mechanism conferring it should potentially reveal a novel arsenal in the cellular machinery.

Show MeSH
Related in: MedlinePlus