Under the gene-for-gene model of host-pathogen coevolution, recognition of pathogen avirulence factors by host resistance factors triggers host defenses and limits infection. Theory predicts that the evolution of higher levels of pathogenicity will be associated with fitness penalties and that the cost of higher pathogenicity must be much smaller than that of not infecting the host. The analysi...

Arabidopsis TOM1 (AtTOM1) and TOM2A (AtTOM2A) are integral membrane proteins genetically identified to be necessary for efficient intracellular multiplication of tobamoviruses. AtTOM1 interacts with the helicase domain polypeptide of tobamovirus-encoded replication proteins and with AtTOM2A, suggesting that both AtTOM1 and AtTOM2A are integral components of the tobamovirus replication complex. ...

Tobamovirus movement proteins play a determinant role in the establishment of infections in plants, allowing the local movement of viral RNA genome through plasmodesmatas. We expressed the movement protein (MP) of the crucifer- and garlic-infecting Tobacco Mosaic Virus strain Cg (TMV-Cg) in both resistant Xanthi NN and sensitive Xanthi nn Nicotiana tabacum plants. MP-Cg function was assayed by ...

The genome of Ob, a tobamovirus that overcomes the N gene-mediated hypersensitive response (HR), was cloned as a cDNA, and its nucleotide sequence was determined. The genomic organization of Ob is similar to that of other tobamoviruses, consisting of 6506 nucleotides and containing at least four open reading frames. These open reading frames encode a 126-kD polypeptide with a 183-kD readthrough...

Resistance conferred by the L(3) gene is active against most of the tobamoviruses, including the Spanish strain (PMMoV-S), a P(1),(2) pathotype, but not against certain strains of pepper mild mottle virus (PMMoV), termed as P(1),(2),(3) pathotype, such as the Italian strain (PMMoV-I). PMMoV-S induces a hypersensitive reaction (HR) in C. chinense PI159236 plant leaves with the formation of necro...

The p24 protein, one of the three proteins implicated in local movement of potato virus X (PVX), was expressed in transgenic tobacco plants (Nicotiana tabacum Xanthi D8 NN). Plants with the highest level of p24 accumulation exhibited a stunted and slightly chlorotic phenotype. These transgenic plants facilitate the cell-to-cell movement of a mutant of PVX that contained a frameshift mutation in...

It was found that the fusion (His)6-movement proteins (MPs) of two tobamoviruses (TMV UI and a crucifer-infecting tobamovirus, crTMV) were efficient nonspecific translational repressors. The in vitro translation of viral RNAs was blocked by incomplete 30K MP-RNA complexes formed at the MP:RNA molar ratios of 100-150:1. Similar results were obtained with the barley stripe mosaic hordeivirus (BSM...

Compared to other vegetable crops, the major viral constraints affecting pepper crops in the Mediterranean basin have been remarkably stable for the past 20 years. Among these viruses, the most prevalent ones are the seed-transmitted tobamoviruses; the aphid-transmitted Potato virus Y and Tobacco etch virus of the genus Potyvirus, and Cucumber mosaic virus member of the genus Cucumovirus; and t...