The inhibitory effects of metabolites from Bacillus pumilus on potato virus Y and the induction of early response genes in Nicotiana tabacum

Shuo Shen,Wei Li

doi:10.1186/s13568-020-01089-1

Abstract

To develop a new antiviral preparation from a microbial source, the halophilic bacterium Bacillus pumilus E303035 was isolated from a soil sample collected at Qarhan Salt Lake in Qinghai, China. The inhibitory activity of an ethyl acetate extract of its fermentation broth was higher than that of an n-butanol extract. After isolation and purification, 9 compounds were obtained: cyclo(L-Leu-L-Pro) (1), cyclo(L-Pro-L-Tyr) (2), Brevianamide F (3), 2-(3-Indolyl) ethanol (4), N-[2-(1H-indol-3-yl) ethyl] acetamide (5), 3, 3-di(1H-indol-3-yl)propane-1,2-diol (6), Lincomycin B (7), dibutylphthalate (8), and p-hydroxyphenethyl alcohol (9). Compounds 1, 5, and 9 showed inhibitory activities against potato virus Y (PVY). Compounds 1, 4, and 9 had significant inhibitory activity against genes HC-pro, P3, and Nib, compound 5 against gene P3, and compounds 1 and 4 against NIa. Compounds 1, 4, 5, and 9 had significant inhibitory activity against genes VPg and 6K1. Active compounds 1, 5, and 9 had various effects on the expression of viral genes related to pathogenesis. Expression of genes cullin and XTH was up-regulated and CP was down-regulated, compared to the positive control. In conclusion, compounds 1, 5, and 9 might be considered as potential antiviral agents for future development.

Highlights

The species Potato virus Y (PVY) is the most important viral pathogen affecting potato crops and a serious threat to potato production worldwide (Davie et al 2017; Funke et al 2017)
In order to illustrate the inhibitory mechanisms of active compounds isolated from strain E303035, the effects were determined on total RNA and on genes encoding the functional proteins of PVY
The genome of PVY is composed of a single-stranded RNA, length 9.7 kb, which covalently links with a viralencoded protein (VPg) at its 5ʹ-end and contains a 3ʹ-polyadenylated tail

Summary

Introduction

The species Potato virus Y (PVY) is the most important viral pathogen affecting potato crops and a serious threat to potato production worldwide (Davie et al 2017; Funke et al 2017). It can infect various crops, including potato, tobacco, tomato, pepper and other crops belonging to the Solanaceae family, and can cause serious damage and significant economic loss (Zhang et al 2017). Bacteria of the genus Bacillus are known to produce a wide range of active substances They have successfully been used to generate compounds such as amylase, proteases, antibiotics, and surfactants (Caetano et al 2011). In order to illustrate the inhibitory mechanisms of active compounds isolated from strain E303035, the effects were determined on total RNA and on genes encoding the functional proteins of PVY

Materials and methods

Discussion