One of the major problems in environmental industries is plant protection using ecologically and human friendly plant resistance inducers. To address this problem in an advantageous way, we used plant sources and substance that is responsible for plant resistance induction as the starting materials to synthesize new ionic liquids (ILs). Engineered ammonium and imidazolium salts with excellent yields of ≥98% were obtained under mild process conditions, using the (−)-menthol moiety, which is economically viable, widely used in many industries, and easily available from natural origins. This monoterpene alcohol, derived from renewable raw resources, was introduced to the cation part of the synthesized ILs. As a counterion, benzo[1.2.3]­thiadiazole-7-carboxylate, which has resistance induction properties in plants, was introduced. In this study, we demonstrated that the careful design of IL’s cations and anions leads to new dual function compounds. This biological property manifests itself as a high level of antimicrobiological activity of the obtained salts, which allows new compounds to be concurrently classified as antimicrobial agents and at the same time as plant resistance inducers. Tested ammonium and imidazolium ILs exhibited antimicrobial activities higher than benzalkonium chloride, which is commonly used in biocides. When analyzing ILs, it was noted that the length of the alkyl chain, presence of the naturally occurring substituent, type of anion, type of cation core, and steric hindrance of the cyclic group are the principal factors determining antimicrobial properties. Work presented in this article shows one of the possibilities of enhancing biological properties, such as resistance induction, of the ILs, by pairing them in a sustainable manner with the antibiocidal agent to form bifunctional salts. Using this approach, it is possible to prepare bifunctional salts that maintain their systemic acquired resistance induction activity at very high levels, enhance solubility in water owing to their ionic characteristics, and deliver additional activities, such as antibacterial. Our design strategy indicates that the choice of the IL components can result in antimicrobial SAR plant resistance inducers, which might be successfully applied as disinfectants or plant resistance inducers.

Systemic acquired resistance (SAR) is one of the most promising ways to support plants in the fight against viruses.

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).

Systemic acquired resistance (SAR) is one of the most promising ways to support plants in fight against viruses, bacteria and fungi. This phenomenon is activated by pathogen attack or artificially, by using resistance inducer (elicitor) which imitates the plant‐pathogen interaction. Both, biological or chemical factors interact with plants and stimulate their immune system against infections before first symptoms of diseases occurs. SAR inducing properties of elicitors could be potentially utilized to develop a new plant protection strategies. This paper presents synthesis, phytotoxicity and SAR induction efficacy of four newly obtained amide derivatives of 2,6‐dichloroisonicotinic acid and four known amide derivatives of isonicotinic acid. Induction of plant resistance tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by Tobacco mosaic virus (TMV). Six of the eight presented substances indicate resistance inducing properties, which were expressed by decrease of necrotic area on leaves caused by viral infection by 44 to 92 % in comparison to the control plants. Moreover, obtained results show that presented compounds exhibited better plant resistance inducing properties than salicylic acid, oxalic acid and β‐aminobutyric acid used as reference.

This article presents the synthesis, physical properties, phytotoxicity, and SAR induction activity of 48 new ionic liquids composed of cations which are choline derivatives and anions of inducers such as salicylic acid, 2,6‐dichloroisonicotinic acid, and benzo[1.2.3]thiadiazole‐7‐carboxylic acid. The cations from which the reported salts were obtained differ in the length of the aliphatic chain bonded to the N,N‐dimethylethanolamine, N,N‐diethylethanolamine, and N,N‐dibutylethanolamine groups. Examination of the obtained series of compounds determined the correlation between the structure of the cation and the biological action of the resistance inducer and investigated the relationship between the structure of the cation and its phytotoxic effect on the plant. Systemic acquired resistance efficacy tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by tobacco mosaic virus (TMV) and phytotoxic tests were performed on Agrimonia eupatoria seeds. The results indicate that the phytotoxicity of salts composed of the same cation increases with the introduction of anions in the following order: salicylate<2,6‐dichloroisonicotinate

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.