Nejvíce citovaný článek - PubMed ID 25904927
Perception of pathogenic or beneficial bacteria and their evasion of host immunity: pattern recognition receptors in the frontline
Being natural plant antimicrobials, saponins have potential for use as biopesticides. Nevertheless, their activity in plant-pathogen interaction is poorly understood. We performed a comparative study of saponins' antifungal activities on important crop pathogens based on their effective dose (EC50) values. Among those saponins tested, aescin showed itself to be the strongest antifungal agent. The antifungal effect of aescin could be reversed by ergosterol, thus suggesting that aescin interferes with fungal sterols. We tested the effect of aescin on plant-pathogen interaction in two different pathosystems: Brassica napus versus (fungus) Leptosphaeria maculans and Arabidopsis thaliana versus (bacterium) Pseudomonas syringae pv tomato DC3000 (Pst DC3000). We analyzed resistance assays, defense gene transcription, phytohormonal production, and reactive oxygen species production. Aescin activated B. napus defense through induction of the salicylic acid pathway and oxidative burst. This defense response led finally to highly efficient plant protection against L. maculans that was comparable to the effect of fungicides. Aescin also inhibited colonization of A. thaliana by Pst DC3000, the effect being based on active elicitation of salicylic acid (SA)-dependent immune mechanisms and without any direct antibacterial effect detected. Therefore, this study brings the first report on the ability of saponins to trigger plant immune responses. Taken together, aescin in addition to its antifungal properties activates plant immunity in two different plant species and provides SA-dependent resistance against both fungal and bacterial pathogens.
- Klíčová slova
- Arabidopsis thaliana, Brassica napus, EC50, Leptosphaeria maculans, Pseudomonas syringae, fungicide, salicylic acid,
- Publikační typ
- časopisecké články MeSH
In a context of a sustainable viticulture, the implementation of innovative eco-friendly strategies, such as elicitor-triggered immunity, requires a deep knowledge of the molecular mechanisms underlying grapevine defense activation, from pathogen perception to resistance induction. During plant-pathogen interaction, the first step of plant defense activation is ensured by the recognition of microbe-associated molecular patterns, which are elicitors directly derived from pathogenic or beneficial microbes. Vitis vinifera, like other plants, can perceive elicitors of different nature, including proteins, amphiphilic glycolipid, and lipopeptide molecules as well as polysaccharides, thanks to their cognate pattern recognition receptors, the discovery of which recently began in this plant species. Furthermore, damage-associated molecular patterns are another class of elicitors perceived by V. vinifera as an invader's hallmark. They are mainly polysaccharides derived from the plant cell wall and are generally released through the activity of cell wall-degrading enzymes secreted by microbes. Elicitor perception and subsequent activation of grapevine immunity end in some cases in efficient grapevine resistance against pathogens. Using complementary approaches, several molecular markers have been identified as hallmarks of this induced resistance stage. This review thus focuses on the recognition of elicitors by Vitis vinifera describing the molecular mechanisms triggered from the elicitor perception to the activation of immune responses. Finally, we discuss the fact that the link between elicitation and induced resistance is not so obvious and that the formulation of resistance inducers remains a key step before their application in vineyards.
Recognition of pathogen-associated molecular patterns (PAMPs) is crucial for plant defence against pathogen attack. The best characterized PAMP is flg22, a 22 amino acid conserved peptide from flagellin protein. In Arabidopsis thaliana, flg22 is recognized by the flagellin sensing 2 (FLS2) receptor. In this study, we focused on biotic stress responses triggered by flg22 after exposure to temporary heat stress (HS). It is important to study the reactions of plants to multiple stress conditions because plants are often exposed simultaneously to a combination of both abiotic and biotic stresses. Transient early production of reactive oxygen species (ROS) is a well-characterized response to PAMP recognition. We demonstrate the strong reduction of flg22-induced ROS production in A. thaliana after HS treatment. In addition, a decrease in FLS2 transcription and a decrease of the FLS2 presence at the plasma membrane are shown after HS. In summary, our data show the strong inhibitory effect of HS on flg22-triggered events in A. thaliana. Subsequently, temporary HS strongly decreases the resistance of A. thaliana to Pseudomonas syringae. We propose that short exposure to high temperature is a crucial abiotic stress factor that suppresses PAMP-triggered immunity, which subsequently leads to the higher susceptibility of plants to pathogens.
- Klíčová slova
- Arabidopsis thaliana, Pseudomonas syringae, PAMP-triggered immunity, flagellin sensing 2 receptor, flg22, heat stress, reactive oxygen species,
- MeSH
- alarminy metabolismus MeSH
- Arabidopsis účinky léků genetika imunologie mikrobiologie MeSH
- flagelin farmakologie MeSH
- genetická transkripce účinky léků MeSH
- imunita rostlin * účinky léků MeSH
- nemoci rostlin imunologie mikrobiologie MeSH
- odolnost vůči nemocem imunologie MeSH
- proteiny huseníčku genetika metabolismus MeSH
- Pseudomonas syringae účinky léků fyziologie MeSH
- reakce na tepelný šok * účinky léků MeSH
- regulace genové exprese u rostlin účinky léků MeSH
- respirační vzplanutí účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- alarminy MeSH
- flagelin MeSH
- proteiny huseníčku MeSH
