Pseudomonas fluorescens DN16 Enhances Cucumber Defense Responses Against the Necrotrophic Pathogen Botrytis cinerea by Regulating Thermospermine Catabolism
Open Access
- 22 February 2021
- journal article
- research article
- Published by Frontiers Media SA in Frontiers in Plant Science
Abstract
Plants can naturally interact with beneficial rhizobacteria to mediate defense responses against foliar pathogen infection. However, the mechanisms of rhizobacteria-mediated defense enhancement remain rarely clear. In this study, beneficial rhizobacterial strain Pseudomonas fluorescens DN16 greatly increased the resistance of cucumber plants against Botrytis cinerea infection. RNA-sequencing analyses showed that several polyamine-associated genes including a thermospermine (TSpm) synthase gene (CsACL5) and polyamine catabolic genes (CsPAO1, CsPAO5, and CsCuAO1) were notably induced by DN16. The associations of TSpm metabolic pathways with the DN16-mediated cucumber defense responses were further investigated. The inoculated plants exhibited the increased leaf TSpm levels compared with the controls. Accordantly, overexpression of CsACL5 in cucumber plants markedly increased leaf TSpm levels and enhanced defense against B. cinerea infection. The functions of TSpm catabolism in the DN16-mediated defense responses of cucumber plants to B. cinerea were further investigated by pharmacological approaches. Upon exposure to pathogen infection, the changes of leaf TSpm levels were positively related to the enhanced activities of polyamine catabolic enzymes including polyamine oxidases (PAOs) and copper amine oxidases (CuAOs), which paralleled the transcription of several defense-related genes such as pathogenesis-related protein 1 (CsPR1) and defensin-like protein 1 (CsDLP1). However, the inhibited activities of polyamine catabolic enzymes abolished the DN16-induced cucumber defense against B. cinerea infection. This was in line with the impaired expression of defense-related genes in the inoculated plants challenged by B. cinerea. Collectively, our findings unraveled a pivotal role of TSpm catabolism in the regulation of the rhizobacteria-primed defense states by mediating the immune responses in cucumber plants after B. cinerea infection.Keywords
This publication has 49 references indexed in Scilit:
- Biosynthesis and function of terpenoid defense compounds in maize (Zea mays)Planta, 2018
- Drought stress tolerance in grapevine involves activation of polyamine oxidation contributing to improved immune response and low susceptibility to Botrytis cinereaJournal of Experimental Botany, 2014
- Potential role of phytohormones and plant growth-promoting rhizobacteria in abiotic stresses: consequences for changing environmentEnvironmental Science and Pollution Research, 2014
- Detection of Hydrogen Peroxide by DAB Staining in Arabidopsis LeavesBio-Protocol, 2012
- Perturbation of spermine synthase Gene Expression and Transcript Profiling Provide New Insights on the Role of the Tetraamine Spermine in Arabidopsis Defense against Pseudomonas viridiflavaPlant Physiology, 2011
- Botrytis cinerea Manipulates the Antagonistic Effects between Immune Pathways to Promote Disease Development in TomatoTHE PLANT CELL ONLINE, 2011
- Abscisic Acid Deficiency Causes Changes in Cuticle Permeability and Pectin Composition That Influence Tomato Resistance to Botrytis cinereaPlant Physiology, 2010
- Plant amine oxidases “on the move”: An updatePlant Physiology and Biochemistry, 2010
- Polyamine biosynthetic diversity in plants and algaePlant Physiology and Biochemistry, 2010
- Functions of amine oxidases in plant development and defenceTrends in Plant Science, 2006