Production and application of Paenibacillus polymyxa levan as an antiviral priming agent against cucumber mosaic virus infection in tobacco plants

Abstract

This study investigates the application of levan- produced from Paenibacillus polymyxa SG09-12 as an antiviral agent against cucumber mosaic virus (CMV). A high-purity microbial levan was produced and purified using diafiltration. The chemical composition, structure, and functional groups of the levan were characterised using high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Antiviral effects of the levan were evaluated in Nicotiana tabacum plants infected with CMV. Treatment with the purified levan significantly attenuated viral symptoms and reduced viral titres, demonstrating a remarkable, long-lasting antiviral effect and highlighting its potential as an antiviral agent. This antiviral effect may have been mediated by transcriptional activation of disease resistance genes encoding RPP13. These findings enhance the understanding of levan produced by Paenibacillus species and their application as an antiviral defense mechanism, which may contribute towards sustainable and environmentally friendly crop protection strategies.

Keywords: Antiviral priming; Cucumber mosaic virus; Levan; Paenibacillus polymyxa; Tobacco.