title: Synergistic enhancement of tolerance mechanisms in response to photoactivation of cationic tetra (N-methylpyridyl) porphyrins in tomato plantlets.
abstract: Antimicrobial photodynamic treatment (APDT) is largely used in medical domain and could be envisaged as a farming practice against crop pathogens such as bacteria and fungi that generate drops in agricultural yields. Thus, as a prerequisite for this potential application, we studied the effect of water-soluble anionic (TPPS and Zn-TPPS) and cationic (TMPyP and Zn-TMPyP) porphyrins tested on tomato (Solanum lycopersicum) plantlets grown in vitro under a 16 h photoperiod. First of all, under dark conditions, none of the four porphyrins inhibited germination and induced cytotoxic effects on tomato plantlets as etiolated development was not altered. The consequences of porphyrin long-term photoactivation (14 days) were thus studied on in vitro-grown tomato plantlets at phenotypic and molecular levels. Cationic porphyrins especially Zn-TMPyP were the most efficient photosensitizers and dramatically altered growth without killing plantlets. Indeed, tomato plantlets were rescued after cationic porphyrins treatment. To gain insight, the different molecular ways implied in the plantlet tolerance to photoactivated Zn-TMPyP, lipid peroxidation, antioxidative molecules (total thiols, proline, ascorbate), and ROS detoxification enzymes were evaluated. In parallel to an increase in lipid peroxidation and hydrogen peroxide production, antioxidative molecules and enzymes (guaiacol peroxidase, catalase, and superoxide dismutase) were up-regulated in root apparatus in response to photoactivated Zn-TMPyP. This study showed that tomato plantlets could overcome the pressure triggered by photoactivated cationic porphyrin by activating antioxidative molecule and enzyme arsenal and confining Zn-TMPyP into cell wall and/or apoplasm, suggesting that APDT directed against tomato pathogens could be envisaged in the future.
authors: Laboratoire de Chimie des Substances Naturelles (EA 1069), Faculté des Sciences et Techniques, Université de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France.
authors: Damien
authors: D
authors: Guillaumot
authors: Laboratoire de Chimie des Substances Naturelles (EA 1069), Faculté des Sciences et Techniques, Université de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France.
authors: Mohammad
authors: M
authors: Issawi
authors: Unité de Génétique Moléculaire et Animale (UMR INRA 1061), Faculté des Sciences et Techniques, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex, France.
authors: Anne
authors: A
authors: Da Silva
authors: Laboratoire de Chimie des Substances Naturelles (EA 1069), Faculté des Sciences et Techniques, Université de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France.
authors: Stephanie
authors: S
authors: Leroy-Lhez
authors: Laboratoire de Chimie des Substances Naturelles (EA 1069), Faculté des Sciences et Techniques, Université de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France.
authors: Vincent
authors: V
authors: Sol
authors: Laboratoire de Chimie des Substances Naturelles (EA 1069), Faculté des Sciences et Techniques, Université de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France. Electronic address: catherine.riou@unilim.fr.
authors: Catherine
authors: C
authors: Riou
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002412:Cations; D018525:Germination; D015227:Lipid Peroxidation; D018551:Solanum lycopersicum / Q000196:embryology / Q000378:metabolism / Q000528:radiation effects*; D017440:Photoperiod; D011166:Porphyrins / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002412:Cations; D011166:Porphyrins; D017382:Reactive Oxygen Species
keywords: Cationic and anionic porphyrins; Photoactivation; ROS production; Solanum lycopersicum