title: Fungal pathogen-induced changes in the antioxidant systems of leaf peroxisomes from infected tomato plants.
abstract: Peroxisomes, being one of the main organelles where reactive oxygen species (ROS) are both generated and detoxified, have been suggested to be instrumental in redox-mediated plant cell defence against oxidative stress. We studied the involvement of tomato (Lycopersicon esculentum Mill.) leaf peroxisomes in defence response to oxidative stress generated upon Botrytis cinerea Pers. infection. The peroxisomal antioxidant potential expressed as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and glutathione peroxidase (GSH-Px, EC 1.11.1.19) as well as the ascorbate-glutathione (AA-GSH) cycle activities was monitored. The initial infection-induced increase in SOD, CAT and GSH-Px indicating antioxidant defence activation was followed by a progressive inhibition concomitant with disease symptom development. Likewise, the activities of AA-GSH cycle enzymes: ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and glutathione reductase (GR, EC 1.6.4.2) as well as ascorbate and glutathione concentrations and redox ratios were significantly decreased. However, the rate and timing of these events differed. Our results indicate that B. cinerea triggers significant changes in the peroxisomal antioxidant system leading to a collapse of the protective mechanism at advanced stage of infection. These changes appear to be partly the effect of pathogen-promoted leaf senescence.
authors.affiliation: Department of Plant Physiology and Biochemistry, University of Łódź, 90-237 Łódź, Banacha 12/16, Poland. elkuz@biol.uni.lodz.pl
authors.forename: Elźbieta
authors.initials: E
authors.lastname: Kuzniak
authors.forename: Maria
authors.initials: M
authors.lastname: Skłodowska
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D020171:Botrytis / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D005979:Glutathione Peroxidase / Q000378:metabolism; D018551:Solanum lycopersicum / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D020675:Peroxisomes / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology* / Q000378:metabolism / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); D001205:Ascorbic Acid