title: Inhibition of SlMPK1, SlMPK2, and SlMPK3 Disrupts Defense Signaling Pathways and Enhances Tomato Fruit Susceptibility to Botrytis cinerea.
abstract: Mitogen-activated protein kinases (MAPKs) are major components of defense signaling pathways that transduce extracellular stimuli into intracellular responses in plants. Our previous study indicated that SlMPK1/2/3 were associated with nitric oxide-induced defense response in tomato fruit. In this study, we determine whether SlMPK1/2/3 influence the tomato fruit's innate immunity and whether plant hormones and reactive oxygen species (ROS) are involved in SlMPK1/2/3 defense signaling pathways. Treatment with 10 μM U0126 significantly inhibited the relative expression of SlMPK1, SlMPK2, and SlMPK3 (P < 0.05). U0126-treated fruit showed higher concentrations of auxin indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA), but a lower concentration of methyl jasmonate (MeJA). The activities of defense enzymes, including β-1,3-glucanases (GLU), chitinase (CHI), phenylalanine ammonia lyase (PAL), and polyphenol oxidase (PPO), decreased after U0126 treatment. Meanwhile, H2O2 content increased, and catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) activities decreased after U0126 treatment. U0126 treatment enhanced the susceptibility of tomato fruit to Botrytis cinerea and resulted in more severe gray mold rot. These results demonstrate that inhibition of SlMPK1/2/3 disrupts tomato fruit defense signaling pathways and enhances the susceptibility to B. cinerea and also that plant hormones and ROS are associated with SlMPK1/2/3 defense signaling pathways.
authors.affiliation: †College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: †College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: †College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Can
authors.initials: C
authors.lastname: Liu
authors.affiliation: †College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: ‡School of Agricultural Economics and Rural Development, Renmin University of China, Beijing 100872, China.
authors.forename: Jiping
authors.initials: J
authors.lastname: Sheng
authors.affiliation: †College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Shen
mesh_terms: D000040:Abscisic Acid / Q000276:immunology; D020171:Botrytis / Q000502:physiology*; D060467:Disease Resistance; D015536:Down-Regulation; D005638:Fruit / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D006861:Hydrogen Peroxide / Q000276:immunology; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000276:immunology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000276:immunology; D015398:Signal Transduction
chemical_list: D010940:Plant Proteins; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases
keywords: Botrytis cinerea; SlMPKs; defense signaling; tomato fruit