Activation of multiple antiviral defence mechanisms by salicylic acid

Singh, Dipendra; Moore, Catherine; Gilliland, Androulla; Carr, John P.

doi:10.1111/j.1364-3703.2004.00203.x

Cited by 127 publications

(94 citation statements)

References 63 publications

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“…Inhibition of cytochrome c oxidase generates an overreduction of the ubiquinone pool that can be alleviated by means of the induction of the alternative oxidase, AOX1a, preventing the formation of ROS (Millenaar and Lambers, 2003;Navrot et al, 2007). Alternative oxidase has been implicated in the regulation of several processes and signaling events, such as thermogenesis, programmed cell death, salicylic acid-induced resistance to viruses, and a response to phosphorus deficiency (Vanlerberghe et al, 2002;Millenaar and Lambers, 2003;Singh et al, 2004). Interestingly, root temperature and P deficiency are environmental factors affecting root hair formation that are regulated by ethylene production (Michael, 2001).…”

Section: Discussionmentioning

confidence: 99%

Mitochondrial β-Cyanoalanine Synthase Is Essential for Root Hair Formation in Arabidopsis thaliana

et al. 2010

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Cyanide is stoichiometrically produced as a coproduct of the ethylene biosynthesis pathway and is detoxified by b-cyanoalanine synthase enzymes. The molecular and phenotypical analysis of T-DNA insertion mutants of the mitochondrial b-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild-type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin or by genetic complementation with the CYS-C1 gene. Hydroxocobalamin not only recovers the root phenotype of the mutant but also the formation of reactive oxygen species at the initial step of root hair tip growth. Transcriptional profiling of the cys-c1 mutant reveals that cyanide accumulation acts as a repressive signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial b-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development.

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Section: Discussionmentioning

confidence: 99%

Mitochondrial β-Cyanoalanine Synthase Is Essential for Root Hair Formation in Arabidopsis thaliana

et al. 2010

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“…SA and JA are well known to play an important role in regulating the defense responses against pathogens (Alvarez 2000;Kova et al 2009;Singh et al 2004) and a fast-growing number of studies are demonstrating that ABA is also implicated in the stress-response signaling network (Asselbergh et al 2008b). Moreover, JA and, more recently, ABA have been shown to be prominent in the establishment and maintenance of the mycorrhizal symbiosis (Gutjahr and Paszkowski 2009;Hause et al 2002Hause et al , 2007Herrera-Medina et al 2007;Isayenkov et al 2005).…”

Section: Hormone Signaling In Mycorrhizal-infected Plantsmentioning

confidence: 99%

Arbuscular Mycorrhizal Symbiosis Limits Foliar Transcriptional Responses to Viral Infection and Favors Long-Term Virus Accumulation

Miozzi¹,

Catoni²,

Fiorilli³

et al. 2011

MPMI

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Tomato (Solanum lycopersicum) can establish symbiotic interactions with arbuscular mycorrhizal (AM) fungi, and can be infected by several pathogenic viruses. Here, we investigated the impact of mycorrhization by the fungus Glomus mosseae on the Tomato spotted wilt virus (TSWV) infection of tomato plants by transcriptomic and hormones level analyses. In TSWV-infected mycorrhizal plants, the AM fungus root colonization limited virus-induced changes in gene expression in the aerial parts. The virus-responsive upregulated genes, no longer induced in infected mycorrhizal plants, were mainly involved in defense responses and hormone signaling, while the virus-responsive downregulated genes, no longer repressed in mycorrhizal plants, were involved in primary metabolism. The presence of the AM fungus limits, in a salicylic acid-independent manner, the accumulation of abscissic acid observed in response to viral infection. At the time of the molecular analysis, no differences in virus concentration or symptom severity were detected between mycorrhizal and nonmycorrhizal plants. However, in a longer period, increase in virus titer and delay in the appearance of recovery were observed in mycorrhizal plants, thus indicating that the plant's reaction to TSWV infection is attenuated by mycorrhization.Arbuscular mycorrhiza (AM) is the term used to describe the mutualistic association between most land plants and fungi from the phylum Glomeromycota (Parniske 2008). The ability to form this association is widely distributed throughout the plant kingdom, and involves most agricultural, horticultural, and hardwood species (Bonfante and Genre 2010). The symbiosis develops in roots where the fungus colonizes the cortex and obtains carbon from the plant while facilitating the transfer of mineral nutrients to the root cells, through differentiated, highly branched intracellular fungal structures called arbuscules (Bonfante and Anca 2009). The benefits of the AM symbiosis on plant fitness are well described, including a better mineral nutrition and increased ability to overcome biotic and abiotic stresses (Aroca et al. 2008;Gernns et al. 2001;Hildebrandt et al. 2007; Pozo and Azcòn-Aguilar 2007;Pozo et al. 2010;van der Heijden and Sanders 2002).The AM symbiosis can have important impacts on plant interactions with pathogens. Alleviation of damage caused by soilborne pathogens has been widely reported in mycorrhizal plants. Most studies deal with the reduction of incidence or severity of soilborne disease. mainly root rot or wilting caused by fungi such as Rhizoctonia, Fusarium, or Verticillium spp., and root rot caused by oomycetes, including Phytophthora, Pythium, and Alphanomyces spp. Experimental evidence also supports the hypothesis that AM symbiosis preconditions plant tissues for a more effective activation of defense responses against stress. This phenomenon, which is also induced in plants by necrotizing pathogens, plant-growth-promoting fungi and rhizobacteria, or treatment with various natural and synthetic compounds, is know...

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“…Indeed, PRs, such as PR-1 and PR-5, have been shown to possess antifungal activity against oomycetes (Van Loon 1997), while SA action in resistance to viruses is likely to rely on a different mechanism (Singh et al, 2004). In contrast, ISR is more active against necrotrophic pathogens (Ton et al, 2002) through mechanisms that are yet to be elucidated.…”

Section: Expression Of Isrmentioning

confidence: 99%

Induced Systemic Resistance as a Mechanism of Disease Suppression by Rhizobacteria

Loon

Bakker

2005

PGPR: Biocontrol and Biofertilization

107

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Abstract:Plant growth-promoting rhizobacteria can suppress diseases through antagonism between the bacteria and soil-borne pathogens, as well as by inducing a systemic resistance in the plant against both root and foliar pathogens. The generally non-specific character of induced resistance constitutes an increase in the level of basal resistance to several pathogens simultaneously, which is of benefit under natural conditions where multiple pathogens may be present. Specific Pseudomonas strains induce systemic resistance in e.g. carnation, cucumber, radish, tobacco and Arabidopsis, as evidenced by an enhanced defensive capacity upon challenge inoculation. Although some bacterial strains are equally effective in inducing resistance in different plant species, others show specificity, indicating specific recognition between bacteria and plants at the root surface. In carnation, radish and Arabidopsis, the O-antigenic side chain of the bacterial outer membrane lipopolysaccharide acts as an inducing determinant, but other bacterial traits are also involved. Pseudobactin siderophores have been implicated in the induction of resistance in tobacco and Arabidopsis, and another siderophore, pseudomonine, may explain induction of resistance associated with salicylic acid (SA) in radish. Although SA induces phenotypically similar systemic acquired resistance (SAR), it is not necessary for the systemic resistance induced by most rhizobacterial strains. Instead, rhizobacteria-mediated induced systemic resistance (ISR) is dependent on jasmonic acid (JA) and ethylene signaling in the plant. Upon challenge inoculation of induced Arabidopsis plants with a pathogen, leaves expressing SAR exhibit a primed expression of SA-, but not JA/ethylene-responsive defense-related genes, whereas leaves expressing ISR are primed to express JA/ethylene-, but not SA-responsive genes. Combination of ISR and SAR can increase protection against pathogens that are resisted through both pathways, as well as extend protection to a broader spectrum of pathogens than ISR or SAR alone.

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Activation of multiple antiviral defence mechanisms by salicylic acid

Cited by 127 publications

References 63 publications

Mitochondrial β-Cyanoalanine Synthase Is Essential for Root Hair Formation in Arabidopsis thaliana

Mitochondrial β-Cyanoalanine Synthase Is Essential for Root Hair Formation in Arabidopsis thaliana

Arbuscular Mycorrhizal Symbiosis Limits Foliar Transcriptional Responses to Viral Infection and Favors Long-Term Virus Accumulation

Induced Systemic Resistance as a Mechanism of Disease Suppression by Rhizobacteria

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