Climate change could promote virus dispersal through seeds

The global trade of seeds is a major contributing factor to the emergence of viral diseases in crops. This is because plant viruses can infect seeds, which represent the main mode of exchange/storage for most plants of agricultural importance. Preventing this venue for global dispersal of viruses requires of understanding the environmental factors that determine the efficiency of virus transmission through seeds, which currently remain elusive. This is particularly important in the current context of climate change that has been predicted to increase the risk of emerging diseases. The group of Dr. Pagán has analyzed whether increased light intensity, a consequence of the reduction of cloud coverage due to global warming, affects the efficiency of plant virus seed transmission. To do so, we used Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV), and its natural host Arabidopsis thaliana as a model system. Therefore, rather than an artificial system, we used plant-virus interactions that occur in nature. In plants infected by these two viruses the group of Dr. Pagán quantified virus multiplication and the effect of infection on seed production at a given virus load. In other words, plant resistance and tolerance, respectively, which are the two major defense mechanisms of plants. The authors also measured the efficiency of CMV and TuMV seed transmission. The results of this research indicate that higher light intensity reduces TuMV resistance and/or increases plant tolerance, which is associated with more efficient seed transmission. Conversely, higher light intensity reduces plant tolerance and increases resistance to CMV, which does not affect virus seed transmission. This work provides novel insights on the potential of climate change conditions to promote the dispersal of plant viruses by modifying the outcome of plant-virus interactions, and contributes to understand the underlying processes. Such knowledge will contribute to design more efficient strategies to control plant virus epidemics.