Importin/exportin-mediated nucleocytoplasmic shuttling of cucumber mosaic virus 2b protein is required for 2b's efficient suppression of RNA silencing.

The 2b protein (2b) of cucumber mosaic virus (CMV), an RNA-silencing suppressor (RSS), is a major pathogenicity determinant of CMV. 2b is localized in the nucleus and cytoplasm, and its nuclear import is determined by two nuclear localization signals (NLSs); a carrier protein (importin [IMPα]) is predicted to be involved in 2b's nuclear transport. Cytoplasmic 2bs play a role in suppression of RNA silencing by binding to small RNAs and AGO proteins.

The 2b protein of Asparagus virus 2 functions as an RNA silencing suppressor against systemic silencing to prove functional synteny with related cucumoviruses.

Asparagus virus 2 (AV-2) is a member of the genus Ilarvirus in the family Bromoviridae. We cloned the coat protein (CP) and the 2b protein (2b) genes of AV-2 isolates from asparagus plants from various regions and found that the sequence for CP and for 2b was highly conserved among the isolates, suggesting that AV-2 from around the world is almost identical. We then made an AV-2 infectious clone by simultaneous inoculation with in vitro transcripts of RNAs 1-3 of AV-2 and in vitro-synthesized CP, which is necessary for initial infection.

Transportation of de novo synthesized jasmonoyl isoleucine in tomato.

In plants, jasmonic acid (JA) and its derivatives are thought to be involved in mobile forms of defense against biotic and abiotic stresses. In this study, the distal transport of JA-isoleucine (JA-Ile) that is synthesized de novo in response to leaf wounding in tomato (Solanum lycopersicum) plants was investigated. JA-[¹³C₆]Ile was recovered in distal untreated leaves after wounded leaves were treated with [¹³C₆]Ile.

Tobacco calmodulin-like protein provides secondary defense by binding to and directing degradation of virus RNA silencing suppressors.

RNA silencing (RNAi) induced by virus-derived double-stranded RNA (dsRNA), which is in a sense regarded as a pathogen-associated molecular pattern (PAMP) of viruses, is a general plant defense mechanism. To counteract this defense, plant viruses express RNA silencing suppressors (RSSs), many of which bind to dsRNA and attenuate RNAi. We showed that the tobacco calmodulin-like protein, rgs-CaM, counterattacked viral RSSs by binding to their dsRNA-binding domains and sequestering them from inhibiting RNAi.

Infection dynamics in viral spread and interference under the synergism between Cucumber mosaic virus and Turnip mosaic virus.

Mixed infection of Cucumber mosaic virus (CMV) and Turnip mosaic virus (TuMV) induced more severe symptoms on Nicotiana benthamiana than single infection. To dissect the relationships between spatial infection patterns and the 2b protein (2b) of CMV in single or mixed infections, the CMV vectors expressing enhanced green fluorescent or Discosoma sp. red fluorescent proteins (EGFP [EG] or DsRed2 [Ds], respectively were constructed from the same wild-type CMV-Y and used for inoculation onto N.

A viral satellite RNA induces yellow symptoms on tobacco by targeting a gene involved in chlorophyll biosynthesis using the RNA silencing machinery.

Symptoms on virus-infected plants are often very specific to the given virus. The molecular mechanisms involved in viral symptom induction have been extensively studied, but are still poorly understood. Cucumber mosaic virus (CMV) Y satellite RNA (Y-sat) is a non-coding subviral RNA and modifies the typical symptom induced by CMV in specific hosts; Y-sat causes a bright yellow mosaic on its natural host Nicotiana tabacum.

The C-terminal residues of the 2b protein of Cucumber mosaic virus are important for efficient expression in Escherichia coli and DNA-binding.

The RNA silencing suppressor 2b protein of Cucumber mosaic virus (CMV) is difficult to produce in Escherichia coli. We compared two CMV 2b proteins that differ in their toxicity against E. coli and found that the acidic amino acid residues in the C-terminal significantly affected the toxicity and expression level of the protein in E.