Search results for "PLANT DEFENCE"
showing 10 items of 15 documents
Mechanisms of Defence to Pathogens : Biochemistry and Physiology
2014
SPE IPM; International audience; Plant defences comprise both pre-existing barriers as well as defences induced upon perception of pathogen-associated molecular patterns (PAMPs) or microbe-associated molecular patterns (MAMPs) or molecules produced from damage as a result of infection (damage-associated molecular patterns (DAMPs)). This chapter focuses on the induced mechanisms of defence. The inducibility of phytoalexin biosynthesis has probably been favoured in the course of evolution by biological constraints such as metabolic costs and functional side-effects associated with chemical defence. Historically, the term ‘hypersensitive’ refers to the rapid and localized cell death induced in…
Type-2 histone deacetylases as new regulators of elicitor-induced cell death in plants
2011
voir Addenda, notes additionnelles complétant l'article : "Dahan, J., Hammoudi, V., Wendehenne, D., Bourque, S. (2011). Type 2 histone deacetylases play a major role in the control of elicitor-induced cell death in tobacco. Plant signaling & behavior, 6 (11), 1865-1867. DOI : 10.4161/psb.6.11.17848".; International audience; Plant resistance to pathogen attack is often associated with a localized programmed cell death called hypersensitive response (HR). How this cell death is controlled remains largely unknown. Upon treatment with cryptogein, an elicitor of tobacco defence and cell death, we identified NtHD2a and NtHD2b, two redundant isoforms of type-2 nuclear histone deacetylases (HDACs…
Involvement of putative glutamate receptors in plant defence signaling and NO production
2011
International audience; Ionotropic glutamate receptors (iGluRs) are non-selective cation channels permeable to calcium, present in animals and plants. In mammals, glutamate is a well-known neurotransmitter and recently has been recognized as an immunomodulator. As animals and plants share common mechanisms that govern innate immunity with calcium playing a key role in plant defence activation, we have checked the involvement of putative iGluRs in plant defence signaling. Using tobacco cells, we first provide evidence supporting the activity of iGluRs as calcium channels and their involvement in NO production as reported in animals. Thereafter, iGluRs were shown to be activated in response t…
Bacterial rhamnolipids are novel MAMPs conferring resistance to Botrytis cinerea in grapevine
2009
International audience; Rhamnolipids produced by the bacteria Pseudomonas aeruginosa are known as very efficient biosurfactant molecules. They are used for a wide range of industrial applications, especially in food, cosmetics and pharmaceutical formulations as well as in bioremediation of pollutants. In this paper, the role of rhamnolipids as novel molecules triggering defence responses and protection against the fungus Botrytis cinerea in grapevine is presented. The effect of rhamnolipids was assessed in grapevine using cell suspension cultures and vitro-plantlets. Ca2+ influx, mitogen-activated protein kinase activation and reactive oxygen species production form part of early signalling…
Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses
2008
International audience; It was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular N…
Egg parasitoid exploitation of plant volatiles induced by single or concurrent attack of a zoophytophagous predator and an invasive phytophagous pest
2019
AbstractZoophytophagous insect predators can induce physiological responses in plants by activating defence signalling pathways, but whether plants can respond to facultative phytophagy by recruiting natural enemies remains to be investigated. In Y-tube olfactometer bioassays, using a system including a Vicia faba plant, the zoophytophagous predator Podisus maculiventris and the egg parasitoid Telenomus podisi, we first demonstrated that T. podisi females are attracted by broad bean plants damaged by feeding activity of P. maculiventris and on which host egg masses had been laid, while they are not attracted by undamaged plants or plants damaged by feeding activity alone. In a second experi…
Mating Status of an Herbivorous Stink Bug Female Affects the Emission of Oviposition-Induced Plant Volatiles Exploited by an Egg Parasitoid
2019
Insect parasitoids are under selection pressure to optimize their host location strategy in order to maximize fitness. In parasitoid species that develop on host eggs, one of these strategies consists in the exploitation of oviposition-induced plant volatiles (OIPVs), specific blends of volatile organic compounds released by plants in response to egg deposition by herbivorous insects. Plants can recognize insect oviposition via elicitors that trigger OIPVs, but very few elicitors have been characterized so far. In particular, the source and the nature of the elicitor responsible of egg parasitoid recruitment in the case of plants induced with oviposition by stink bugs are still unknown. In …
Nitric oxide inhibits the ATPase activity of the chaperone-like AAA+ ATPase CDC48, a target for S-nitrosylation in cryptogein signalling in tobacco c…
2012
NO has important physiological functions in plants, including the adaptative response to pathogen attack. We previously demonstrated that cryptogein, an elicitor of defence reaction produced by the oomycete Phytophthora cryptogea , triggers NO synthesis in tobacco. To decipher the role of NO in tobacco cells elicited by cryptogein, in the present study we performed a proteomic approach in order to identify proteins undergoing S-nitrosylation. We provided evidence that cryptogein induced the S-nitrosylation of several proteins and identified 11 candidates, including CDC48 (cell division cycle 48), a member of the AAA+ ATPase (ATPase associated with various cellular activities) family. In vit…
Attraction of egg-killing parasitoids toward induced plant volatiles in a multi-herbivore context
2015
In response to insect herbivory, plants emit volatile organic compounds which may act as indirect plant defenses by attracting natural enemies of the attacking herbivore. In nature, plants are often attacked by multiple herbivores, but the majority of studies which have investigated indirect plant defenses to date have focused on the recruitment of different parasitoid species in a single-herbivore context. Here, we report our investigation on the attraction of egg parasitoids of lepidopteran hosts (Trichogramma brassicae and T. evanescens) toward plant volatiles induced by different insect herbivores in olfactometer bioassays. We used a system consisting of a native crucifer, Brassica nigr…
Plant responses induced by Halyomorpha halys (Het.: Pentatomidae)
2016
The Brown Marmorated Stink Bug Halyomorpha halys (Heteroptera: Pentatomidae), is a very polyphagous pest of fruit crops, horticultural crops and ornamentals. Native from eastern Asia, this invasive species was recorded for the first time in Modena in 2012 and is now spreading in Northern and Central Italy. With its establishment in the invaded areas, new interactions with native tri-trophic systems (plants - stink bugs - parasitoids) are expected. A plant attacked by an ovipositing stink bug may respond by the emission of induced plant synomones, which are exploited by egg parasitoids for host location (indirect defences). This mechanism had been studied for coevolved tritrophic systems at …