The Effects of Turnip Mosaic Virus Infections on the Deposition of Secondary Cell Walls and Developmental Defects in Arabidopsis Plants Are Virus-Strain Specific

Abstract

Two isolates of Turnip mosaic virus (UK 1 and JPN 1), representative of two different viral strains, induced differential alterations on secondary cell wall (SCW) development in Arabidopsis thaliana, suggesting cell-type specific effects of these viral infections. These potential effects were analyzed in inflorescence stems and flowers of infected plants, together with other possible cellular effects of the infections. Results obtained from macroscopic and histochemical analyses showed that infection with either virus significantly narrowed stem area, but defects in SCW were only found in JPN 1 infections. In flowers, reduced endothecium lignification was also found for JPN 1, while UK 1 infections induced severe floral cell and organ development alterations. A transcriptomic analysis focused on genes controlling and regulating SCW formation also showed notable differences between both viral isolates. UK 1 infections induced a general transcriptional decrease of most regulatory genes, whereas a more complex pattern of alterations was found in JPN 1 infections. The role of the previously identified viral determinant of most developmental alterations, the P3 protein, was also studied through the use of viral chimeras. No SCW alterations or creeping habit growth were found in infections by the chimeras, indicating that if the P3 viral protein is involved in the determination of these symptoms, it is not the only determinant. Finally, considerations as to the possibility of a taxonomical reappraisal of these TuMV viral strains are provided.

Within-host virus spreading and tolerance to infection are key factors of theArabidopsis thalianaage-dependent susceptibility to viral infections

“…We hypothesize that the loosening of cell walls on these hosts may facilitate the deformation of plasmodesmata and enable the faster spread of the virus from one cell to another and, ultimately, to the entire host via the phloem. In line with our results, López-González et al . (2021) showed that TuMV-infected plants downregulate genes related with the formation of the secondary cell wall.…”

“…The copyright holder for this this version posted November 21, 2023. ; https://doi.org/10.1101/2023.11.21.568017 doi: bioRxiv preprint 9 ultimately, to the entire host via the phloem. In line with our results, López-González et al (2021) showed that TuMV-infected plants downregulate genes related with the formation of the secondary cell wall. They found that IRREGULAR XYLEM 9, a gene related with xylan synthesis (a key component of the secondary cell wall), was strongly downregulated upon TuMV infection.…”