Activities of antioxidant enzymes and photosynthetic responses in tomato pre-treated by plant activators and inoculated by Xanthomonas vesicatoria |
| |
Authors: | Fabio Rossi Cavalcanti Mario Lucio Vilela Resende Joo Paulo Matos Santos Lima Joaquim Albenisio Gomes Silveira Jos Tadeu Abreu Oliveira |
| |
Institution: | aCampus Cinobelina Elvas, Universidade Federal do Piauí, CEP 64900-000, Bom Jesus, Piauí, Brazil;bDepartamento de Fitopatologia, Universidade Federal de Lavras, CP 3037, CEP 37200-000, Minas Gerais, Brazil;cDepartamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, CP 6033, CEP 60451-970, Fortaleza, Ceará, Brazil |
| |
Abstract: | The activities of antioxidant enzymes and photosynthetic responses were investigated in tomato (Lycopersicon esculentum L. var.) pre-treated by plant activators and inoculated by Xanthomonas vesicatoria. Plants were sprayed with acibenzolar-S-methyl, ASM Bion® 50 WG (0.2 g l−1)] and aqueous extract from dry necrotic tissue flour (VLA) of ‘Lobeira’ (Solanum lycocarpum) bush. Four days later, the plants were challenged with a virulent strain of X. vesicatoria, under greenhouse conditions. Tomato leaves were then assessed to determine the activities of the main antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX). A reduction of bacterial leaf spot severity was observed in plants treated by ASM (49.3%) and VLA (31.4%), without any in vitro inhibitory activity over the pathogen. Controls showed decreases in CO2 assimilation, transpiration, photosynthetic rates, and stomatal conductance. Water use efficiency and carboxylation efficiency were strongly affected in ASM- and VLA-treated, in comparison to controls and healthy plants. The tested substances induced increases in SOD and CAT activities in a delayed enzymatic response typical in compatible plant–pathogen interactions. Measured at daily intervals, activities of APX and POX were significantly (ρ0.05) higher in treated plants than in controls, except for APX in ASM-treated plants where no difference was found when compared to controls. Only POX was clearly induced at the earlier stages after spraying the tomato plants with ASM or VLA. Our results suggest that late increases in antioxidant enzyme activities may play a role in mitigating oxidative damage in restoring the photosynthetic imbalance imposed by the expansion of bacterial lesions. |
| |
Keywords: | Acibenzolar-S-methyl (ASM) Antioxidant enzyme Bacterial leaf spot Bion 50  WG Chlorophyll fluorescence Gas exchange Induced resistance Natural extract ROS Solanum lycocarpum Tomato |
本文献已被 ScienceDirect 等数据库收录! |
|