Expression and antiviral function of ARGONAUTE 2 in Nicotiana benthamiana plants infected with two isolates of tomato ringspot virus with varying degrees of virulence

Citation

Paudel, D.B., Ghoshal, B., Jossey, S., Ludman, M., Fatyol, K., Sanfaçon, H. (2018). Expression and antiviral function of ARGONAUTE 2 in Nicotiana benthamiana plants infected with two isolates of tomato ringspot virus with varying degrees of virulence. Virology, [online] 524 127-139. http://dx.doi.org/10.1016/j.virol.2018.08.016

Plain language summary

In this article, we describe how the plant defense response to virus infection is influenced by the specific virus strain and by growing conditions. We used two different virus strains and two growing temperatures and showed that the severity of symptoms was strongly affected by both the temperature and the virus strain. We found that the expression of a key plant antiviral gene (Argonaute 2) is affected by these parameters. In addition, we also provide evidence that other factors (in addition to Argonaute 2) determines the outcome of infection. The results highlight the complexity of plant defense responses and the impact of environmental conditions and will assist in developing informed strategies for the management of virus diseases especially in the context of climate change.

Abstract

ARGONAUTEs (notably AGO1 and AGO2) are effectors of plant antiviral RNA silencing. AGO1 was shown to be required for the temperature-dependent symptom recovery of Nicotiana benthamiana plants infected with tomato ringspot virus (isolate ToRSV-Rasp1) at 27 °C. In this study, we show that symptom recovery from isolate ToRSV-GYV shares similar hallmarks of antiviral RNA silencing but occurs at a wider range of temperatures (21–27 °C). At 21 °C, an early spike in AGO2 mRNAs accumulation was observed in plants infected with either ToRSV-Rasp1 or ToRSV-GYV but the AGO2 protein was only consistently detected in ToRSV-GYV infected plants. Symptom recovery from ToRSV-GYV at 21 °C was not prevented in an ago2 mutant or by silencing of AGO1 or AGO2. We conclude that other factors (possibly other AGOs) contribute to symptom recovery under these conditions. The results also highlight distinct expression patterns of AGO2 in response to ToRSV isolates and environmental conditions.

Publication date

2018-11-01

Author profiles