Derivatives of Isonicotinic Acid as New Efficient Systemic Acquired Resistance (SAR) Inducers

New plant resistance inducers based on polyamines

The novel and revolutionary approach to plant protection presented in this work, based on the preparation of bifunctional salts of a plant resistance inducer combined with a polyamine cation, may become a potential solution in the future for reducing the effects of abiotic and biotic stresses to which the plant is exposed. This study presents the synthesis, physical properties, phytotoxicity, and systemic acquired resistance (SAR) induction efficacy of new salts composed of the anion of plant resistance inducers and N,N,N,N′,N′,N′-hexamethylpropane-1,3-diammonium cation (5 salts), N,N,N,N′,N′,N′-hexamethyl-butane-1,4-diammonium cation (5 salts), spermidine salicylate, and spermine salicylate. SAR induction efficiency tests were performed on tobacco, Nicotiana tabacum var. Xanthi, infected with the tobacco mosaic virus.

Transcriptome analysis reveals the mechanism of zinc ion-mediated plant resistance to TMV in Nicotiana benthamiana

Zinc ions (Zn2+) are used to promote plant growth and treat multiple diseases. However, it is still unclear which pathways in plants respond to Zn2+. In this study, we found that supplying (CH3COO)2Zn can effectively delay tobacco mosaic virus (TMV) replication and movement in Nicotiana benthamiana. To further understand the regulatory mechanism of antiviral activity mediated by Zn2+, we examined the transcriptomic changes of leaves treated with Zn2+. Three days after treatment, 7575 differential expression genes (DEGs) were enriched in the Zn2+ treatment group compared with the control group. Through GO and KEGG analysis, the pathway of phosphatidylinositol signaling system and inositol phosphate metabolism were significantly enriched after treated with Zn2+, and a large number of ethylene-responsive transcription factors (ERFs) involved in inositol phosphate metabolism were found to be enriched. We identified ERF5 performed a positive effect on plant immunity. Our findings demonstrated that Zn2+-mediated resistance in N. benthamiana activated signal transduction and regulated the expression of resistance-related genes. The results of the study uncover a global view of mRNA changes in Zn2+-mediated cellular processes involved in the competition between plants and viruses.

Alginate-Induced Disease Resistance in Plants

Plants are continuously exposed to a wide range of pathogens, including fungi, bacteria, nematodes, and viruses; therefore, survival under these conditions requires a sophisticated defense system. The activation of defense responses and related signals in plants is regulated mainly by the hormones salicylic acid, jasmonic acid, and ethylene. Resistance to pathogen infection can be induced in plants by various biotic and abiotic agents. For many years, the use of abiotic plant resistance inducers has been considered in integrated disease management programs. Recently, natural inducer compounds, such as alginates, have become a focus of interest due to their environmentally friendly nature and their ability to stimulate plant defense mechanisms and enhance growth. Polysaccharides and the oligosaccharides derived from them are examples of eco-compatible compounds that can enhance plant growth while also inducing plant resistance against pathogens and triggering the expression of the salicylic acid-dependent defense pathway.

Simple modifications of nicotinic, isonicotinic, and 2,6-dichloroisonicotinic acids toward new weapons against plant diseases

Recently, the biggest challenge in agriculture is the search for new, effective, and ecological methods of protecting plants against diseases. One of the fastest-growing and prospective strategies is a method based on activating the plant’s natural defenses. The use of suitable substances (elicitors) stimulates the immune system of plants, which makes them resistant to infections even before the first symptoms appear. This article presents preparation, characterization, phytotoxicity, and plant resistance induction efficacy of 28 ester derivatives of nicotinic, isonicotinic, and 2,6-dichloroisonicotinic acids as potential inducers of plants’ natural immune system. Plant resistance induction efficacy tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by the tobacco mosaic virus (TMV).