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RNA silencing is required for Arabidopsis defence against Verticillium wilt disease.

Ellendorff U, Fradin EF, de Jonge R, Thomma BP - J. Exp. Bot. (2008)

Bottom Line: Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses.Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence.Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, 6709 PD Wageningen, The Netherlands.

ABSTRACT
RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses. In this study, it is shown that gene silencing plays a role in plant defence against multicellular microbial pathogens; vascular fungi belonging to the Verticillium genus. Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence. Remarkably, no altered defence towards other fungal pathogens that include Alternaria brassicicola, Botrytis cinerea, and Plectosphaerella cucumerina, but also the vascular pathogen Fusarium oxysporum, was recorded. Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses.

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Typical symptoms caused by F. oxysporum on Arabidopsis sgs mutants. The mutants sgs1-1, sgs2-1, sgs3-1, and the corresponding wild type Col-0 were inoculated with F. oxysporum f.sp. raphani, or mock-inoculated. The picture was taken at 12 d post-inoculation.
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fig2: Typical symptoms caused by F. oxysporum on Arabidopsis sgs mutants. The mutants sgs1-1, sgs2-1, sgs3-1, and the corresponding wild type Col-0 were inoculated with F. oxysporum f.sp. raphani, or mock-inoculated. The picture was taken at 12 d post-inoculation.

Mentions: To investigate whether the enhanced pathogen susceptibility phenotype of the sgs mutants extended to other pathogens in addition to Verticillium species, the susceptibility of the sgs1-1, sgs2-1, and sgs3-1 mutants towards the vascular fungus F. oxysporum f.sp. raphani (Diener and Ausubel, 2005) was tested. However, disease development on the three sgs mutants did not differ from disease development on Col-0 plants upon inoculation with this pathogen (Fig. 2). Furthermore, a number of additional fungal and bacterial pathogens was tested on the sgs mutants (see Supplementary Table S1 at JXB online; Wang et al., 2008). These comprised the foliar fungal pathogens Botrytis cinerea, Alternaria brassicicola, and Plectosphaerella cucumerina, and virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. However, for none of these pathogens was altered susceptibility observed in the sgs mutants when compared with Col-0 (data not shown). Thus, the enhanced susceptibility of the sgs mutants is specific for Verticillium pathogens and does not extend to other pathogens.


RNA silencing is required for Arabidopsis defence against Verticillium wilt disease.

Ellendorff U, Fradin EF, de Jonge R, Thomma BP - J. Exp. Bot. (2008)

Typical symptoms caused by F. oxysporum on Arabidopsis sgs mutants. The mutants sgs1-1, sgs2-1, sgs3-1, and the corresponding wild type Col-0 were inoculated with F. oxysporum f.sp. raphani, or mock-inoculated. The picture was taken at 12 d post-inoculation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2651451&req=5

fig2: Typical symptoms caused by F. oxysporum on Arabidopsis sgs mutants. The mutants sgs1-1, sgs2-1, sgs3-1, and the corresponding wild type Col-0 were inoculated with F. oxysporum f.sp. raphani, or mock-inoculated. The picture was taken at 12 d post-inoculation.
Mentions: To investigate whether the enhanced pathogen susceptibility phenotype of the sgs mutants extended to other pathogens in addition to Verticillium species, the susceptibility of the sgs1-1, sgs2-1, and sgs3-1 mutants towards the vascular fungus F. oxysporum f.sp. raphani (Diener and Ausubel, 2005) was tested. However, disease development on the three sgs mutants did not differ from disease development on Col-0 plants upon inoculation with this pathogen (Fig. 2). Furthermore, a number of additional fungal and bacterial pathogens was tested on the sgs mutants (see Supplementary Table S1 at JXB online; Wang et al., 2008). These comprised the foliar fungal pathogens Botrytis cinerea, Alternaria brassicicola, and Plectosphaerella cucumerina, and virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. However, for none of these pathogens was altered susceptibility observed in the sgs mutants when compared with Col-0 (data not shown). Thus, the enhanced susceptibility of the sgs mutants is specific for Verticillium pathogens and does not extend to other pathogens.

Bottom Line: Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses.Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence.Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, 6709 PD Wageningen, The Netherlands.

ABSTRACT
RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses. In this study, it is shown that gene silencing plays a role in plant defence against multicellular microbial pathogens; vascular fungi belonging to the Verticillium genus. Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence. Remarkably, no altered defence towards other fungal pathogens that include Alternaria brassicicola, Botrytis cinerea, and Plectosphaerella cucumerina, but also the vascular pathogen Fusarium oxysporum, was recorded. Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses.

Show MeSH
Related in: MedlinePlus