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US-12616204-B2 - Use of cationic porphyrins as selective herbicide

US12616204B2US 12616204 B2US12616204 B2US 12616204B2US-12616204-B2

Abstract

The present invention relates to the use of cationic porphyrins such as zinc tetra(N-methylpyridyl)porphyrin tetrachloride and tetra(N-methylpyridyl)porphyrin tetrachloride or a mixture thereof, as selective foliar herbicidal agent.

Inventors

  • Mohamad ISSAOUI
  • Catherine Riou
  • VINCENT SOL

Assignees

  • UNIVERSITE DE LIMOGES

Dates

Publication Date
20260505
Application Date
20220217
Priority Date
20210218

Claims (17)

  1. 1 . A selective weed-control method in a cultivation area, comprising applying one or more cationic porphyrins selected from a zinc tetra(N-methylpyridyl)porphyrin tetrachloride, a tetra(N-methylpyridyl)porphyrin tetrachloride and a mixture thereof; said porphyrins being applied by foliar spraying onto the cultivation area, wherein the cultivation area contains both crop and non-crop plants and wherein the porphyrins selectively kill the non-crop plants.
  2. 2 . The method as claimed in claim 1 , characterized in that the one or more cationic porphyrins are zinc tetra(N-methylpyridyl)porphyrin tetrachlorides.
  3. 3 . The method as claimed in claim 1 , characterized in that the cultivation area is selected from a field, a greenhouse, a meadow, a yard, a fairway, a garden, and a vegetable garden.
  4. 4 . The method of claim 1 , wherein the cultivation area comprises one or more crops of a genus selected from the group consisting of Nicotiana, Solanum, Vitis, Hordeum, Triticum, Zeya, Helianthus, Allium, Spinacia, Fragaria and Brassica.
  5. 5 . The method as claimed in claim 1 , wherein the cultivation area comprises one or more crops selected from wheat ( Triticum sativum ), barley ( Hordeum vulgare ), corn ( Zeya mays ), sunflower ( Helianthus annuus ), turnip ( Brassica rapa ), tomato ( Solanum lycopersicum ), onion ( Allium cepa ) and spinach ( Spinacia oleracea ) crops.
  6. 6 . The method as claimed in claim 1 , characterized in that said one or more cationic porphyrins have an herbicidal effect on weeds of a genus selected from the group consisting of Urtica, Echinochloa, Papaver, Lolium, Datura, Stellaria, Chenopodium, Panicum, Taraxacum, Rumex , and Solanum.
  7. 7 . The method as claimed in claim 1 , characterized in that said one or more cationic porphyrins have an herbicidal effect on weeds selected from black nightshade ( Solanum nigrum ), dandelion ( Taraxacum officinale ), white goosefoot ( Chenopodium album ), dock ( Rumex crispus ), Italian rye-grass ( Lolium multiflorum ), proso millet ( Panicum miliaceum ), chickweed ( Stellaria media ), millet ( Echinochloa frumentacea ) and poppy ( Papaver rhoeas ).
  8. 8 . The method as claimed in claim 1 , characterized in that said one or more cationic porphyrins are applied at a cotyledon stage and/or at a first-leaf stage.
  9. 9 . The method as claimed in claim 8 , wherein the first-leaf stage is a 2-leaf stage and/or a 4-leaf stage.
  10. 10 . The method as claimed in claim 1 , wherein the cultivation area is a field, a greenhouse, a meadow, a yard, a fairway, a garden, or a vegetable garden.
  11. 11 . The method according to claim 1 , wherein said one or more cationic porphyrins are applied by at least two foliar applications.
  12. 12 . The method according to claim 1 , wherein said one or more cationic porphyrins are in the form of a composition comprising at least one surfactant selected from neutral, nonionic, anionic, cationic, and zwitterionic neutral surfactants.
  13. 13 . The method according to claim 1 , wherein said one or more cationic porphyrins are applied by at least two foliar applications and are in the form of a composition comprising at least one surfactant selected from neutral, nonionic, anionic, cationic, and zwitterionic neutral surfactants.
  14. 14 . The method according to claim 12 , wherein said surfactant is selected from polyoxyethylene nonylphenyl ether, benzalkonium chloride (BAC), and benzethonium chloride (BZT).
  15. 15 . The method according to claim 13 , wherein said surfactant is selected from polyoxyethylene nonylphenyl ether, benzalkonium chloride (BAC), and benzethonium chloride (BZT).
  16. 16 . The method according to claim 1 , wherein the porphryins are present in a composition having a concentration of porphryins of at least 50 μM.
  17. 17 . The method according to claim 1 , wherein the cultivation area does not contain Arabidopsis thaliana.

Description

TECHNICAL FIELD The present invention relates to the use of cationic porphyrins such as zinc tetra(N-methylpyridyl)porphyrin tetrachloride and tetra(N-methylpyridyl)porphyrin tetrachloride or a mixture thereof, as selective foliar herbicidal agent. PRIOR ART Photosensitizers (PS) are molecules capable of inducing, by virtue of a light stimulus and in the presence of oxygen, the formation of reactive oxygen species (ROSs) that are more or less toxic for living cells, depending on their physicochemical properties, the concentrations used and also the nature of the cells and biological organisms. There are two mechanisms of ROSs production: The type I mechanism, which involves a transfer of electrons from the photosensitizer to biological substrates so as to form free radicals (superoxide anion O2−, hydroxyl radical OH and hydrogen peroxide H2O2);the type II mechanism which for its part involves the transfer of energy to molecular dioxygen, which passes from its ground state (triplet state: 3O2) to the singlet state 1O2. These photosensitizers are mainly used in the medical field, in the context of photodynamic therapy in cancer treatment but also for the fight against microorganisms such as bacteria and fungi, as disinfection therapy or for the decontamination of water and foodstuffs. In general, ROSs are deleterious to all living cells. These photosensitizers have therefore been envisaged for application as biocides in the agricultural field, and more particularly against crop pathogens such as bacteria and fungi, which cause reductions in agricultural yield. The use of these photosensitizers as biocide is also called antimicrobial photodynamic therapy. However, although needed, studies evaluating the undesirable effects of photosensitizers on plants are rare. Moreover, the effects of molecules on plants are very difficult to transpose between different species. Typically, natural photosensitizers (coumarins and furocoumarins) have been evaluated as biocides on orange trees and strawberry plants. While orange tree leaves were not affected by the photosensitizers, strawberry plant leaves were damaged by the coumarins. Cationic water-soluble porphyrins (zinc tetra(N-methylpyridyl)porphyrin tetrachloride (Zn-TMPyP) and tetra(N-methylpyridyl)porphyrin tetrachloride (TMPyP)) have also been applied to tomato seedlings (Solanum lycopersicum) cultivated in vitro under a 16-hour photoperiod. It was demonstrated that the cationic porphyrins significantly altered the seedling growth in vitro. However, the authors suggest that these photosensitizers could be used as biocides against tomato pathogens (Guillaumot et al., Synergistic enhancement of tolerance mechanisms in response to photoactivation of cationic tetra(N-methylpyridyl) porphyrins in tomato plantlets, Journal of Photochemistry and Photobiology B: Biology, Volume 156, March 2016, pages 69-78). However, these same cationic porphyrins, also tested in vitro on Arabidopsis seedlings (Arabidopsis thaliana), completely killed the plant at very low dose (3.5 μM) (Issawi et al., Responses of an adventitious fast-growing plant to photodynamic stress: comparative study of anionic and cationic porphyrin effect on Arabidopsis thaliana, Physiologia Plantarum (162): 379-390. 2018). While the in vitro root effect of photosensitizers on plants is unpredictable and difficult to extrapolate to field or greenhouse conditions, and while cationic porphyrins such as Zn-TMPyP applied in vitro at best inhibit the growth of the plants tested and at worst destroy them, the inventors have, unexpectedly, demonstrated that cationic porphyrins and preferentially TMPyP and Zn-TMPyP are selective weedkillers when they are applied by foliar spraying. SUMMARY The present invention therefore relates to the use of cationic porphyrins selected from zinc tetra(N-methylpyridyl)porphyrin tetrachloride (Zn-TMPyP) and tetra(N-methylpyridyl)porphyrin tetrachloride (TMPyP) or a mixture thereof, as selective foliar herbicide. The inventors have specifically advantageously demonstrated that Zn-TMPyP can be used as a selective foliar herbicide. While Zn-TMPyP significantly inhibits plant development (adventitious plants and plants of agronomic interest) when it is applied to plant roots in vitro, the inventors have demonstrated that Zn-TMPyP preserves plants of agronomic interest and does not affect their development when Zn-TMPyP is applied by foliar spraying, typically in a greenhouse. In contrast, this same method (foliar application of Zn-TMPyP in a greenhouse) leads to the death of adventitious plants. Zn-TMPyP is therefore a selective foliar herbicide that makes it possible to combat adventitious plants while preserving crops of agronomic interest. Moreover, TMPyP and Zn-TMPyP are advantageously photodegradable, thus making it possible to limit their long-term effect. Their non-toxicity to fishing worms (maggots) has also been demonstrated. Still advantageously, TMPyP and Zn-TMPyP are effective at lo