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

Silvia López-González,Fernando Ponz,Flora Sánchez,A Lacey Samuels,Concepción Gómez-Mena,Mathias Schuetz

doi:10.3389/fpls.2021.741050

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.

Highlights

Viruses often induce disease symptoms in the infected host, which in plants include mottles or mosaics, yellowing, or stunted growth
Infections of Arabidopsis thaliana with Turnip mosaic virus (TuMV, a potyvirus) alter a number of developmental stages that we identified in practically all plant organs in a comparative analysis between virus strains (Sánchez et al, 2015)
Since the infection by TuMV has a strong impact on Arabidopsis global morphogenesis, in this work, we have focused on the effects of the virus on secondary cell wall (SCW) formation and composition, and in the transcriptomics of the genes involved in the regulation of their formation

Summary

Introduction

Viruses often induce disease symptoms in the infected host, which in plants include mottles or mosaics, yellowing, or stunted growth. These general symptoms have long been recognized, are observed and well documented. Plants infected with the viral isolate UK 1 were not able to elongate a stem, or produced only a very short stem with no flowers, or a few sterile ones. Those infected with isolate JPN 1 elongated a creeping inflorescence stem, which is unable to maintain upright growth. No information is available about the viral determinant of the creeping and branching

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Conclusion