Molecular Regulation of Host Defense Responses Mediated by Biological Anti-TMV Agent Ningnanmycin

Abstract

Ningnanmycin (NNM) belongs to microbial pesticides that display comprehensive antiviral activity against plant viruses. NNM treatment has been shown to efficiently delay or suppress the disease symptoms caused by tobacco mosaic virus (TMV) infection in local-inoculated or systemic-uninoculated tobacco leaves, respectively. However, the underlying molecular mechanism of NNM-mediated antiviral activity remains to be further elucidated. In this study, 414 differentially expressed genes (DEGs), including 383 which were up-regulated and 31 down-regulated, caused by NNM treatment in TMV-infected BY-2 protoplasts, were discovered by RNA-seq. In addition, KEGG analysis indicated significant enrichment of DEGs in the plant–pathogen interaction and MAPK signaling pathway. The up-regulated expression of crucial DEGs, including defense-responsive genes, such as the receptor-like kinase FLS2, RLK1, and the mitogen-activated protein kinase kinase kinase MAPKKK, calcium signaling genes, such as the calcium-binding protein CML19, as well as phytohormone responsive genes, such as the WRKY transcription factors WRKY40 and WRKY70, were confirmed by RT-qPCR. These findings provided valuable insights into the antiviral mechanisms of NNM, which indicated that the agent induces tobacco systemic resistance against TMV via activating multiple plant defense signaling pathways.

Chimeric Tobamoviruses With Coat Protein Exchanges Modulate Symptom Expression and Defence Responses in Nicotiana tabacum

“…WRKY40 was reported to associate with a transcription factor BZR1 to mediate plant immune signaling (Lozano-Durán et al, 2013). In a previous study, we have also shown that WRKY40 was up-regulated by an anti-viral biological agent Ningnanmycin (An et al, 2019), which also confirmed the function of WRKY40 in plant immune responses. It was revealed that Arabidopsis WRKY50 together with TGA transcription factors synergistically activate expression of PR1 (Hussain et al, 2018), which were in agreement with our results showing that expression of PR1 together with WRKY50 were consistently up-regulated by infection of chimeric TMV.…”

Effectiveness of disinfectants against the spread of tobamoviruses: Tomato brown rugose fruit virus and Cucumber green mottle mosaic virus

“…Similarly, SP2700, with its active ingredient ningnanmycin, is a biopesticide derived from a fermentation broth of Streptomyces noursei var. xichangensis resulting in an effective, efficient and low cost antimicrobial compound [63,64]. SP2700 was shown to directly deactivate the TMV particles when incubated with 0.5 mM (6.8 G/L) for 30 min.…”

Wild Species Veronica officinalis L. and Veronica saturejoides Vis. ssp. saturejoides—Biological Potential of Free Volatiles

“…In addition, among the essential oils extracted from 29 indigenous Chinese aromatic plants, the oils of ginger, lemon, tea tree, tangerine peel, artemisia, and lemongrass caused more than 50% inhibition of TMV at the concentrations tested [26,27]. In addition to plant extracts, inhibitors of plant viruses derived from metabolites of microbes are also considered as potential alternatives to chemical pesticides [45]. Ningnanmycin isolated from the fermentation broth of Streptomyces noursei var.…”