rgs-CaM Detects and Counteracts Viral RNA Silencing Suppressors in Plant Immune Priming

Jeon, Eun Jin; Tadamura, Kazuki; Murakami, Taiki; Inaba, Jun-ichi; Kim, Bo Min; Sato, Minoru; Atsumi, Go; Kuchitsu, Kazuyuki; Masuta, Chikara; Nakahara, Kenji

doi:10.1128/jvi.00761-17

Cited by 38 publications

(28 citation statements)

References 77 publications

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“…This constitutes the first example of an interaction between a CML and a pathogen protein [ 111 ]. Recently, the role of this rgs-CaM in systemic acquired resistance against cucumber mosaic virus has been described in tobacco plants [ 113 ]. It was proposed that rgs-CaM functions as an immune receptor that induces salicylic acid signalling by simultaneously perceiving both viral RNA silencing suppressors and Ca 2+ influx [ 113 ].…”

Section: Ca 2+ Decoding Processes and Plant Immmentioning

confidence: 99%

Calcium Signalling in Plant Biotic Interactions

Aldon

Mbengue

Mazars

et al. 2018

IJMS

255

137

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Calcium (Ca2+) is a universal second messenger involved in various cellular processes, leading to plant development and to biotic and abiotic stress responses. Intracellular variation in free Ca2+ concentration is among the earliest events following the plant perception of environmental change. These Ca2+ variations differ in their spatio-temporal properties according to the nature, strength and duration of the stimulus. However, their conversion into biological responses requires Ca2+ sensors for decoding and relaying. The occurrence in plants of calmodulin (CaM) but also of other sets of plant-specific Ca2+ sensors such as calmodulin-like proteins (CMLs), Ca2+-dependent protein kinases (CDPKs) and calcineurin B-like proteins (CBLs) indicate that plants possess specific tools and machineries to convert Ca2+ signals into appropriate responses. Here, we focus on recent progress made in monitoring the generation of Ca2+ signals at the whole plant or cell level and their long distance propagation during biotic interactions. The contribution of CaM/CMLs and CDPKs in plant immune responses mounted against bacteria, fungi, viruses and insects are also presented.

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Section: Ca 2+ Decoding Processes and Plant Immmentioning

confidence: 99%

Calcium Signalling in Plant Biotic Interactions

Aldon

Mbengue

Mazars

et al. 2018

IJMS

255

137

View full text Add to dashboard Cite

show abstract

“…This requires an interaction between the VSRs and rgsCaM, a calmudolin-like protein and an endogenous suppressor of silencing, which is itself destined to autophagic degradation. Interestingly, rgsCaM is also a component of the SA-mediated systemic acquired resistance ( Jeon et al, 2017 ).…”

Section: Molecular Mechanisms Aimed At Limiting the Accumulation Or Amentioning

confidence: 99%

Exploring the Diversity of Mechanisms Associated With Plant Tolerance to Virus Infection

Paudel

Sanfaçon

2018

Front. Plant Sci.

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Tolerance is defined as an interaction in which viruses accumulate to some degree without causing significant loss of vigor or fitness to their hosts. Tolerance can be described as a stable equilibrium between the virus and its host, an interaction in which each partner not only accommodate trade-offs for survival but also receive some benefits (e.g., protection of the plant against super-infection by virulent viruses; virus invasion of meristem tissues allowing vertical transmission). This equilibrium, which would be associated with little selective pressure for the emergence of severe viral strains, is common in wild ecosystems and has important implications for the management of viral diseases in the field. Plant viruses are obligatory intracellular parasites that divert the host cellular machinery to complete their infection cycle. Highjacking/modification of plant factors can affect plant vigor and fitness. In addition, the toxic effects of viral proteins and the deployment of plant defense responses contribute to the induction of symptoms ranging in severity from tissue discoloration to malformation or tissue necrosis. The impact of viral infection is also influenced by the virulence of the specific virus strain (or strains for mixed infections), the host genotype and environmental conditions. Although plant resistance mechanisms that restrict virus accumulation or movement have received much attention, molecular mechanisms associated with tolerance are less well-understood. We review the experimental evidence that supports the concept that tolerance can be achieved by reaching the proper balance between plant defense responses and virus counter-defenses. We also discuss plant translation repression mechanisms, plant protein degradation or modification pathways and viral self-attenuation strategies that regulate the accumulation or activity of viral proteins to mitigate their impact on the host. Finally, we discuss current progress and future opportunities toward the application of various tolerance mechanisms in the field.

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“…Although the role of autophagy in defense against bacterial and viral pathogens in animals has been intensively studied, how autophagy functions in plant-virus interaction remains to be fully understood. In plants, Cucumber mosaic virus 2b and potyviruses HC-Pro are thought to be targeted for autophagic degradation via the calmodulin-like protein rgs-CaM (Nakahara et al, 2012;Jeon et al, 2017). Tomato yellow leaf curl virus proteins are also thought to be partially degraded by autophagy (Gorovits et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Barley stripe mosaic virus γb Protein Subverts Autophagy to Promote Viral Infection by Disrupting the ATG7-ATG8 Interaction

et al. 2018

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Autophagy is a conserved defense strategy against viral infection. However, little is known about the counterdefense strategies of plant viruses involving interference with autophagy. Here, we show that γb protein from (BSMV), a positive single-stranded RNA virus, directly interacts with AUTOPHAGY PROTEIN7 (ATG7). BSMV infection suppresses autophagy, and overexpression of γb protein is sufficient to inhibit autophagy. Furthermore, silencing of autophagy-related gene and in plants enhanced BSMV accumulation and viral symptoms, indicating that autophagy plays an antiviral role in BSMV infection. Molecular analyses indicated that γb interferes with the interaction of ATG7 with ATG8 in a competitive manner, whereas a single point mutation in γb, Tyr29Ala (Y29A), made this protein deficient in the interaction with ATG7, which was correlated with the abolishment of autophagy inhibition. Consistently, the mutant BSMV virus showed reduced symptom severity and viral accumulation. Taken together, our findings reveal that BSMV γb protein subverts autophagy-mediated antiviral defense by disrupting the ATG7-ATG8 interaction to promote plant RNA virus infection, and they provide evidence that ATG7 is a target of pathogen effectors that functions in the ongoing arms race of plant defense and viral counterdefense.

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rgs-CaM Detects and Counteracts Viral RNA Silencing Suppressors in Plant Immune Priming

Cited by 38 publications

References 77 publications

Calcium Signalling in Plant Biotic Interactions

Calcium Signalling in Plant Biotic Interactions

Exploring the Diversity of Mechanisms Associated With Plant Tolerance to Virus Infection

Barley stripe mosaic virus γb Protein Subverts Autophagy to Promote Viral Infection by Disrupting the ATG7-ATG8 Interaction

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