The Potential of Molecular Indicators of Plant Virus Infection: Are Plants Able to Tell Us They Are Infected?

Gardette R Valmonte-Cortes,Michael N Pearson,Robin M Macdiarmid,Sonia T Lilly,Colleen M Higgins

doi:10.3390/plants11020188

Gardette R Valmonte-Cortes, Michael N Pearson + Show 3 more

Open Access

https://doi.org/10.3390/plants11020188

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Abstract

To our knowledge, there are no reports that demonstrate the use of host molecular markers for the purpose of detecting generic plant virus infection. Two approaches involving molecular indicators of virus infection in the model plant Arabidopsis thaliana were examined: the accumulation of small RNAs (sRNAs) using a microfluidics-based method (Bioanalyzer); and the transcript accumulation of virus-response related host plant genes, suppressor of gene silencing 3 (AtSGS3) and calcium-dependent protein kinase 3 (AtCPK3) by reverse transcriptase-quantitative PCR (RT-qPCR). The microfluidics approach using sRNA chips has previously demonstrated good linearity and good reproducibility, both within and between chips. Good limits of detection have been demonstrated from two-fold 10-point serial dilution regression to 0.1 ng of RNA. The ratio of small RNA (sRNA) to ribosomal RNA (rRNA), as a proportion of averaged mock-inoculation, correlated with known virus infection to a high degree of certainty. AtSGS3 transcript decreased between 14- and 28-days post inoculation (dpi) for all viruses investigated, while AtCPK3 transcript increased between 14 and 28 dpi for all viruses. A combination of these two molecular approaches may be useful for assessment of virus-infection of samples without the need for diagnosis of specific virus infection.

Highlights

Virus infections in plants pose a major threat to agricultural, environmental, and economic security globally [1,2]
Agarose gel electrophoresis comparing healthy and Turnip mosaic virus (TuMV)infected A. thaliana RNA samples suggested an increase in accumulation of small RNA (sRNA) among infected plants (Figure 1a)
This study investigated the potential use of sRNA and specific mRNA targets as molecular markers that would indirectly indicate virus infection in plants

Summary

Introduction

Virus infections in plants pose a major threat to agricultural, environmental, and economic security globally [1,2]. Strict monitoring of viruses and other pathogens that may arrive with plant materials is implemented as part of border biosecurity by several/many countries [3,4]. In-field monitoring of viruses (and other pathogens) is becoming increasingly important [5,6]. Available detection tools are limited, with regards to plant virus detection. Current available assays are limited to symptom observation, visualisation of virus particles, and serological and molecular tests to detect virus particles or nucleic acids [7]. Symptom observation may be inaccurate and insufficient to differentiate viral infections from other types of pathogen infection or abiotic stress [8]

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