Transcriptomic and Functional Analyses Indicate Novel Anti-viral Mode of Actions on Tobacco Mosaic Virus of a Microbial Natural Product ε-Poly-l-lysine

Abstract

Novel anti-viral natural product ε-poly-l-lysine (ε-PL) produced by Streptomyces is a homopolymer of l-lysine, of which the underlying molecular mode of action remains to be further elucidated. In this study, ε-PL induced significant fragmentation of tobacco mosaic virus (TMV) virions and delayed the systemic infection of TMV-GFP as well as wild-type TMV in plants. ε-PL treatment also markedly inhibited RNA accumulation of TMV in tobacco BY-2 protoplasts. The results of RNA-seq indicated that the agent induced significantly differential expression of genes that are associated with defense response, stress response, autophagy, and ubiquitination. Among them, 15 critical differential expressed genes were selected for real-time quantitative PCR validation. We further demonstrated that ε-PL can induce host defense responses by assessing the activity of several defense-related enzymes in plants. Our results provided valuable insights into molecular anti-viral mode of action for ε-PL, which is expected to be applied as a novel microbial natural product against plant virus diseases.

ε-poly-L-lysine Affects the Vegetative Growth, Pathogenicity and Expression Regulation of Necrotrophic Pathogen Sclerotinia sclerotiorum and Botrytis cinerea

“…The ε-PL was mainly applied to inhibit bacteria and was well-characterized as a food preservative [54]. In the previous study, we investigated the functions of ε-PL on the induction of host defense responses against the infection of the tobacco mosaic virus (TMV) [25], as well as the anti-fungal mechanisms of ε-PL on A. alternata [21]. The ε-PL was reported to effectively inhibit the incidence of grey mold rot on various fruits and vegetables caused by B. cinerea [23,26].…”

“…The anti-bacterial activity of ε-PL was well investigated using Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa [17,19,20], while recent research focused on its effect on other plant pathogens, including viruses and fungi [21][22][23]. Our previous study showed that ε-PL significantly suppressed the infection of the tobacco mosaic virus (TMV) in Nicotiana glutinosa, as well as RNA accumulation in tobacco protoplasts and induced host defensive responses [24,25]. In addition, we indicated that ε-PL effectively inhibited vegetative growth and pathogenicity and affected the respective gene expression of Alternaria alternata [21].…”

Effects of ε-Poly-L-Lysine Combined with Wuyiencin as a Bio-Fungicide against Botryris cinerea

“…Treatment with ε-PL in tobacco BY-2 protoplasts significantly downregulated Tobacco Mosaic Virus (TMV) RNA accumulation and induced the host defense response, suggesting ε-PL as a natural microbial to treat plant virus diseases [ 13 ]. In addition, ε-PL markedly inhibited Alternaria alternata disease progression by reducing germ tube elongation and spore germination and downregulating the expression of crucial fungal development-related genes [ 14 ]. In addition, the incidence of gray mold rot (caused by Botryris cinerea ) on a variety of fruit and vegetables was effectively inhibited by ε-PL [ 15 , 16 ].…”

Extraction, purification and anti-TMV effects of α (β)-2,7,11-cembratriene-4,6-diol from tobacco leaves

“…The reference gene EF-1a was used for quantitative analysis. The relative expression levels of the tested genes were calculated with the 2 −ΔΔCt method[27]. The primer sequences used are shown in Supplementary Table 1.…”