Within-Host Multiplication and Speed of Colonization as Infection Traits Associated with Plant Virus Vertical Transmission

Abstract

One of the major factors contributing to plant virus long-distance dispersal is the global trade of seeds. This is because more than 25% of plant viruses can infect seeds, which are the main mode of germplasm exchange/storage, and start new epidemics in areas where they were not previously present. Despite the relevance of this process for virus epidemiology and disease emergence, the infection traits associated with the efficiency of virus seed transmission are largely unknown. Using turnip mosaic and cucumber mosaic viruses and their natural host Arabidopsis thaliana as model systems, we have identified the within-host speed of virus colonization and multiplication in the reproductive structures as the main determinants of the efficiency of seed transmission. These results contribute to shedding light on the mechanisms by which plant viruses disperse and optimize their fitness and may help in the design of more-efficient strategies to prevent seed infection.

Light Intensity Modulates the Efficiency of Virus Seed Transmission through Modifications of Plant Tolerance

“…In summary, light intensity modulates the effect of infection on plant growth, reproduction and development. Previous work associated tolerance to TuMV with changes in the plant developmental schedule and that to CMV with modifications of resource reallocation from growth to reproduction [40,42]. Our results would be compatible with these previous works.…”

“…On the other hand, no significant differences between allometric groups were observed in the accumulation of any of the three viruses at any light intensity (Wald χ 2 1,281 ≤ 1.29, p ≥ 0.256). Hence, light intensity affects one of the main infection traits associated with virus seed transmission [40].…”

“…Hence, reduced virulence would favor plant virus seed transmission. Recently, the efficiency of seed transmission has been also associated with higher virus multiplication in reproductive organs [40]. Thus, environmental conditions that favor reduced virus virulence without controlling its level of within-plant multiplication (by definition, tolerance) may enhance vertical transmission.…”

“…Upon CMV infection, increasing light intensity has been shown to favor Arabidopsis tolerance, but this conclusion was based on analyses in a reduced number of plant accessions [25]. Interestingly, CMV [45,46] and TuMV [40] have been shown to be vertically-transmitted in Arabidopsis, the efficiency of seed transmission being associated with higher virus load in the plant inflorescence and with reduced virulence [40]. Thus, the selected experimental system provides an ideal opportunity to analyze the interaction between light intensity, plant tolerance to virus infection and the efficiency of seed transmission.…”

Nanoparticles as Potential Antivirals in Agriculture

“…In plants, vertical transmission through seeds is common. The mechanisms of transmission are through contamination of the seed coat or invasion of the seed embryo indirectly by infection of plant gametes before fertilization or directly from the mother plant to the embryonic tissue after fertilization [107]. The potential use of MeNPs as seed antivirals due to their antimicrobial properties and their size may limit the pathogen in the seed.…”