Cross-Talk in Viral Defense Signaling in Plants

Cotton blue disease (CBD) is the most important disease present in cotton crops in South America and cotton leafroll dwarf virus (CLRDV) is the causal agent. The disease has been controlled by sowing cotton varieties resistant to CLRDV. However, in the 2009/10 growing season, an outbreak due to an atypical CLRDV isolate (CLRDV‐at) occurred in northwest Argentina. Although CLRDV and CLRDV‐at genomes are very closely related, the symptoms they produce in cotton plants are quite different. P0 is the most divergent protein between the isolates and in CLRDV is a silencing suppressor protein. This work characterized the silencing suppressor activity of the P0 protein encoded by CLRDV‐at (P0CL‐at) and evaluated its role in Cbd‐resistance break in cotton plants. It was demonstrated that P0CL‐at, despite having a mutation in the consensus of the F‐box‐like motif, was able to suppress local RNA silencing, but displayed lower activity than P0CL. P0CL and P0CL‐at showed no differences in the interaction with Gossypium hirsutum SKP1 orthologue (GSK1) and Nicotiana benthamiana SKP1 and both P0 proteins triggered destabilization of ARGONAUTE1. However, when the ability to enhance PVX symptoms was evaluated, P0CL‐at was shown to be a weaker pathogenicity factor than P0CL in N. benthamiana. Interestingly, trans‐expressed P0CL‐at enabled CLRDV to systemically infect CBD‐resistant plants, and a chimeric CLRDV‐P0CL‐at infectious clone succeeded in establishing infection in CBD‐resistant cotton varieties with symptoms resembling those produced by CLRDV‐at. These results strongly suggest that P0CL‐at is the avirulence (Avr) determinant involved in breaking cotton Cbd gene‐based resistance.

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“…Many studies have postulated a link between plant immunity and RNA silencing (Ding, ; Moon & Park, ). For instance, Ishibashi et al .…”

Section: Discussionmentioning

confidence: 99%

P0 protein of cotton leafroll dwarf virus‐atypical isolate is a weak RNA silencing suppressor and the avirulence determinant that breaks the cotton Cbd gene‐based resistance

et al. 2019

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“…For non‐viral pathogens, plant PTI and mammalian innate immune systems share similar activation mechanisms, including a similar structural configuration of PRRs and similar conserved PAMPs. However, plant antiviral PTI has been conceptually regarded as RNA silencing, in which viral dsRNAs are considered PAMPs, which activate Dicers as PRRs that can be suppressed by viral effectors (Calil and Fontes, ; Moon and Park, ). More recently, accumulated evidence has invoked the classic PTI initiated by transmembrane PRRs as part of the plant defence arsenal against viruses.…”

Section: Introductionmentioning

confidence: 99%

Virus perception at the cell surface: revisiting the roles of receptor‐like kinases as viral pattern recognition receptors

Teixeira

Ferreira

Raimundo

et al. 2019

Molecular Plant Pathology

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Summary Activation of antiviral innate immune responses depends on the recognition of viral components or viral effectors by host receptors. This virus recognition system can activate two layers of host defence, pathogen‐associated molecular pattern (PAMP)‐triggered immunity (PTI) and effector‐triggered immunity (ETI). While ETI has long been recognized as an efficient plant defence against viruses, the concept of antiviral PTI has only recently been integrated into virus–host interaction models, such as the RNA silencing‐based defences that are triggered by viral dsRNA PAMPs produced during infection. Emerging evidence in the literature has included the classical PTI in the antiviral innate immune arsenal of plant cells. Therefore, our understanding of PAMPs has expanded to include not only classical PAMPS, such as bacterial flagellin or fungal chitin, but also virus‐derived nucleic acids that may also activate PAMP recognition receptors like the well‐documented phenomenon observed for mammalian viruses. In this review, we discuss the notion that plant viruses can activate classical PTI, leading to both unique antiviral responses and conserved antipathogen responses. We also present evidence that virus‐derived nucleic acid PAMPs may elicit the NUCLEAR SHUTTLE PROTEIN‐INTERACTING KINASE 1 (NIK1)‐mediated antiviral signalling pathway that transduces an antiviral signal to suppress global host translation.

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“…The presence of a period with low within-host virus accumulation may restrict the cumulative effects of virus on host individuals during a year. Regarding the mechanisms to keep virus accumulation low, there are many studies on the antiviral defences of plants, such as RNA silencing, hypersensitive response, systemic acquired resistance, and their cross-talks [26][27][28][29]; however, whether the relative importance of these antiviral mechanisms varies across seasons is still unknown.…”

Section: Introductionmentioning

confidence: 99%

Seasonality of interactions between a plant virus and its host during persistent infection in a natural environment

et al. 2019

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Persistent infection, wherein a pathogen is continually present in a host individual, is widespread in virus-host systems. However, little is known regarding how seasonal environments alter virus-host interaction during such metastability. We observed a lineage-to-lineage infection of the host plant Arabidopsis halleri with Turnip mosaic virus for 3 years without severe damage. Virus dynamics and virus-host interactions within hosts were highly season dependent. Virus accumulation in the newly formed leaves was temperature dependent and was suppressed during winter. Transcriptome analyses suggested that distinct defence mechanisms, i.e. salicylic acid (SA)-dependent resistance and RNA silencing, were predominant during spring and autumn, respectively. Transcriptomic difference between infected and uninfected plants other than defence genes appeared transiently only during autumn in upper leaves. However, the virus preserved in the lower leaves is transferred to the clonal offspring of the host plants during spring. In the linage-to-linage infection of the A. halleri-TuMV system, both host clonal reproduction and virus transmission into new clonal rosettes are secured during the winter-spring transition. How virus and host overwinter turned out to be critical for understanding a long-term virus-host interaction within hosts under temperate climates, and more generally, understanding seasonality provides new insight into ecology of plant viruses.

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Cross-Talk in Viral Defense Signaling in Plants

Cited by 56 publications

References 60 publications

P0 protein of cotton leafroll dwarf virus‐atypical isolate is a weak RNA silencing suppressor and the avirulence determinant that breaks the cotton Cbd gene‐based resistance

P0 protein of cotton leafroll dwarf virus‐atypical isolate is a weak RNA silencing suppressor and the avirulence determinant that breaks the cotton Cbd gene‐based resistance

Virus perception at the cell surface: revisiting the roles of receptor‐like kinases as viral pattern recognition receptors

Seasonality of interactions between a plant virus and its host during persistent infection in a natural environment

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