New Dual Functional Salts Based on Cationic Derivative of Plant Resistance Inducer—Benzo[1.2.3]thiadiazole-7-carbothioic Acid, S-Methyl Ester

Abstract

Plant resistance induction is one of the most promising ways to support plants in fights against pathogens, especially viruses, due to the fact there are no plant protection agents acting directly on them. Certain chemicals, including benzo[1.2.3]­thiadiazole-7-carbothioic acid, S-methyl ester (BTH) and its derivatives, were discovered as effective inducers of plant immunity. In this article, new BTH derivatives, in the form of organic salts composed of cations based on the plant resistance inducer BTH and anions introduced in order to modify physical (solubility in water, dissolution rate, thermal stability, melting points, pK a and logP values), and biological (antibacterial) properties are presented. The physical properties of resulting salts were altered by, for example, changing water solubility and also through the introduction of a second ion with a biological function (bacteriostatic and bactericidal properties against Gram-positive and Gram-negative bacteria). The major impact this new approach in plant protection may have is that the synthetic plant resistance inducers (used in very low dosages) may in the future become an alternative to the pesticides commonly used in large amounts, thus significantly reducing the use of harmful chemicals in agriculture and their negative impact on the environment and human health.

A Novel Plant Resistance Inducer for the Protection of European Ash (Fraxinus excelsior L.) against Hymenoscyphus fraxineus—Preliminary Studies

“…On the other hand, our substance can decompose in small amounts by the interaction of an active substance with soil component; however, its availability to plants is still higher, which has been confirmed by limited sizes and number of necrotic phloem lesions. Our previous studies have shown that a group of used ionic derivatives of benzothiadiazole can act as effective plant resistance inducers [22,23]. The experiments were carried out with Nicotiana tabacum var.…”

“…To trigger the SAR in plants, the infectious agent or resistanceinducing molecules such as salicylic acid [16], benzo[1.2.3]thiadiazole-7-carbothioic acid S-methyl ester (BTH) [17], and their derivatives [18][19][20][21] must be present. Our previous studies have shown that a group of ionic derivatives of benzothiadiazole can act as effective plant resistance inducers [22,23], with lower (eco)toxicity and higher biodegradability than the commercially available BTH [24]. The most effective plant resistance inducer discovered by us, a water-based formulation of N-methyl, N-methoxy-7-carboxybenzo[1-3]thiadiazole (BTHWA), the experimental product by Innosil company [25,26], in addition to high efficiency, has shown the highest level of SAR marker genes associated with pathogen defense response [27].…”

Use of New BTH Derivative as Supplement or Substitute of Standard Fungicidal Program in Strawberry Cultivation

“…Our hitherto study has been focused on the synthesis of ionic derivatives of benzo(1.2.3)thiadiazole-7-carboxylic acid and isonicotinic acid acting as dual functional salts [15][16][17][18][19]. The dual functionality of the synthesized salts, known as the ionic liquids, was preserved by maintaining resistance inducing properties with additional direct antibacterial function [15,17,18]. The most effective salts, which were functional analogues of salicylic acid and BTH derivatives, allowed 100% induction in tobacco in the tobacco mosaic virus (TMV) model, at the same time demonstrating high antibacterial activity towards plant pathogens [16].…”

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

“…[8][9][10] SAR inducers can be divided into two groups: natural (endogenous) like salicylic acid, oxalic acid, nicotinic acid and synthetic -2,6-dichloroisonicotinic acid, β-aminobutyric acid acibenzolar S-methyl ester (BTH) and their derivatives. [11][12][13][14][15][16][17][18] There are many advantage of using elicitors to induce the SAR phenomenon as a method of plant protection: (1) they do not directly interact with microorganisms which results in maintenance of the environmental equilibrium; [19] (2) elicitors activate plant resistance which has broad spectrum of actions against pathogens, most often simultaneously against fungi, viruses and bacteria; [4][5] (3) pathogens do not immunize against SAR inducers because those do not interact directly with the pathogens, furthermore, in contrast to typical plant protection products, pathogens do not immunize against systemic acquired resistance itself because this phenomenon is too complex; [20] (4) elicitors can be used in combination with another plant protection products to reduce their doze; [21] (5) method of application of SAR inducers is the same as typical plant protection techniques against pathogens. [8] In summary, high efficiency and broad spectrum of action against patho- gens makes application of SAR inducers to plant a very promising method of plant protection.…”