Letteratura scientifica selezionata sul tema "Phytocytokine"

The plant immunity system is being revisited more and more and new elements and roles are attributed to participating in the response to biotic stress. The new terminology is also applied in an attempt to identify different players in the whole scenario of immunity: Phytocytokines are one of those elements that are gaining more attention due to the characteristics of processing and perception, showing they are part of a big family of compounds that can amplify the immune response. This review aims to highlight the latest findings on the role of phytocytokines in the whole immune response to biotic stress, including basal and adaptive immunity, and expose the complexity of their action in plant perception and signaling events.

Danger signals trigger immune responses upon perception by a complex surveillance system. Such signals can originate from the infectious nonself or the damaged self, the latter termed damage-associated molecular patterns (DAMPs). Here, we apply Matzinger's danger model to plant innate immunity to discuss the adaptive advantages of DAMPs and their integration into preexisting signaling pathways. Constitutive DAMPs (cDAMPs), e.g., extracellular ATP, histones, and self-DNA, fulfill primary, conserved functions and adopt a signaling role only when cellular damage causes their fragmentation or localization to aberrant compartments. By contrast, immunomodulatory peptides (also known as phytocytokines) exclusively function as signals and, upon damage, are activated as inducible DAMPs (iDAMPs). Dynamic coevolutionary processes between the signals and their emerging receptors and shared co-receptors have likely linked danger recognition to preexisting, conserved downstream pathways.

AbstractPlant plasma membrane-resident immune receptors regulate plant immunity by recognizing microbe-associated molecular patterns (MAMPs), damage-associated molecular patterns (DAMPs), and phytocytokines. Phytocytokines are plant endogenous peptides, which are usually produced in the cytosol and released into the apoplast when plant encounters pathogen infections. Phytocytokines regulate plant immunity through activating an overlapping signaling pathway with MAMPs/DAMPs with some unique features. Here, we highlight the current understanding of phytocytokine production, perception and functions in plant immunity, and discuss how plants and pathogens manipulate phytocytokine signaling for their own benefits during the plant-pathogen warfare.

Phytocytokines are signalling peptides that alarm plant cells of danger. However, the downstream responses triggered by phytocytokines and their effect on plant survival are still largely unknown. Here, we have identified three biologically active maize orthologues of phytocytokines previously described in other plants. The maize phytocytokines show common features with microbe-associated molecular patterns (MAMPs), including the induction of immune-related genes and activation of papain-like cysteine proteases. In contrast to MAMPs, phytocytokines do not promote cell death in the presence of wounding. In infection assays with two fungal pathogens we found that phytocytokines affect the development of disease symptoms, likely due to the activation of phytohormonal pathways. Collectively, our results show that phytocytokines and MAMPs trigger unique and antagonistic features of immunity. We propose a model in which phytocytokines activate immune responses partially similar to MAMPs but in contrast to microbial signals, they act as danger and survival molecules to the surrounding cells. Future studies will focus on the components determining the divergence of signalling outputs upon phytocytokine activation.

Abstract Small signaling peptides play important roles in various plant processes, but information regarding their involvement in plant immunity is limited. We previously identified a novel small secreted protein in rice, named immune response peptide 1 (IRP1). Here, we studied IRP1 functions in rice immunity. Rice plants overexpressing IRP1 enhanced resistance to the virulent rice blast fungus. Application of IRP1 peptide to rice suspension cells triggered the expression of IRP1 itself and the defense gene PAL1. RNA-seq results revealed that 84% of genes upregulated by IRP1 peptide were also induced by a microbe-associated molecular pattern(MAMP) chitin, including 13 OsWRKY transcription factors, indicating that IRP1 and chitin share a similar signaling pathway. Co-treatment with chitin and IRP1 elevated the expression level of PAL1 and OsWRKYs in an additive manner. The increased chitin concentration arrested the induction of IRP1 and PAL1 expressions by IRP1, but cannot affect IRP1-triggered MAPK activation. Collectively, our findings indicate that IRP1 functions as a phytocyokine in rice immunity regulating MAPKs and OsWRKYs that could amplify chitin and other signaling pathways, and provide new insights into how MAMPs and phytocyokines cooperatively regulate rice immunity.

Les plantes possèdent un système immunitaire capable de stopper la progression des agents pathogènes et de prévenir l'apparition des maladies. Ce système immunitaire utilise des peptides de défense pouvant avoir deux fonctions distinctes: antimicrobiennes ou élicitrices. Rust Induced Secreted Peptide from Populus trichocarpa (PtRISP1) est un peptide du peuplier qui présente à la fois une activité antimicrobienne envers les champignons de l'ordre des Pucciniales et une activité élicitrice des réponses immunitaires chez le peuplier. Les objectifs de la thèse étaient de caractériser le mode d'action antifongique et éliciteur de PtRISP1 et de ses homologues et d'entreprendre des démarches de valorisation de ces peptides comme composés anti-pucciniales. Cette thèse comporte cinq chapitres : un chapitre d'introduction, trois chapitres de résultats, et un chapitre de discussion. Le Chapitre I présente une synthèse bibliographique portant sur l'immunité des plantes, les peptides de défense, les Salicacées, les Pucciniales, et le peptide PtRISP1. Le Chapitre II présente des résultats concernant l'activité élicitrice des peptides RISP. Il montre notamment qu'au sein des génomes des peupliers et des saules, les gènes RISP sont systématiquement regroupés avec des gènes codant pour des récepteurs membranaires de type Leucine Rich Repeat Receptor Proteins (LRR-RP), que nous avons appelés RISP-Associated LRR-RPs (RALR), et que les RALR reconnaissent les peptides RISP pour induire la signalisation immunitaire. Le Chapitre III présente des résultats concernant l'activité antimicrobienne de PtRISP1. Il montre notamment que PtRISP1 cible les extrémités apicales des urédospores de Melampsora larici-populina via des régions protéiques chargées, a une activité spécifique envers les Pucciniales, et s'attache à la surface des feuilles. Le Chapitre IV présente une analyse préliminaire de la famille RISP, qui montre que des membres divergents de la famille présentent des activités anti-Pucciniales et des propriétés biophysiques similaires à PtRISP1. Enfin, le Chapitre V discute les résultats de la thèse en les replaçant dans un contexte plus large et met en perspective la valorisation des peptides végétaux en agriculture. Pour conclure, ces travaux de thèse ont mis en évidence que les peptides RISP sont des phytocytokines reconnues par des récepteurs immunitaires spécifiques, possèdent une activité antimicrobienne spécifique envers les Pucciniales, et ont évolué conjointement avec leurs récepteurs chez les arbres de la famille des Salicacées
Plants have an immune system able to stop the progress of pathogens and prevent the development of disease. This immune system uses defense peptides that can have two distinct functions: antimicrobial or elicitor. Rust Induced Secreted Peptide from Populus trichocarpa (PtRISP1) is a peptide from poplar that exhibits both antimicrobial activity against fungi of the order Pucciniales and elicitor activity in poplar. The objectives of the thesis were to characterize the antifungal and elicitor mode of action of PtRISP1 and its homologues, and to initiate steps to valorize these peptides as anti-pucciniales compounds. This thesis comprises five chapters: an introduction, three results chapters and a discussion chapter. The Chapter I presents a synthesis of the literature on plant immunity, defense peptides, Salicaceae, Pucciniales and the PtRISP1 peptide. Chapter II presents results concerning the elicitor activity of RISP peptides. In particular, it shows that within the poplar and willow genomes, RISP genes are systematically clustered with genes encoding Leucine Rich Repeat Receptor Proteins (LRR-RP), which we have called RISP-Associated LRR-RPs (RALRs), and that RALRs recognize RISP peptides to induce immune signaling. The Chapter III presents the results concerning the antimicrobial activity of PtRISP1. In particular, it shows that PtRISP1 targets the apical tips of Melampsora larici-populina urediniospores via charged protein regions, has specific activity towards Pucciniales, and attaches to leaf surfaces. The Chapter IV presents a preliminary analysis of the RISP family, showing that divergent family members exhibit anti-Pucciniales activities and biophysical properties similar to PtRISP1. Finally, the Chapter V discusses the results of the thesis, placing them in a more wider context and putting the valorization of plant peptides in agriculture into perspective. In conclusion, this thesis work has demonstrated that RISP peptides are phytocytokines recognized by specific immune receptors, have a specific antimicrobial activity towards Pucciniales, and have co-evolved with their receptors in trees of the Salicaceae family

En tant qu’organismes sessiles, les plantes doivent réagir rapidement et intensément, via des réponses défensives, pour repousser les pathogènes invasifs. Le système immunitaire des plantes peut être déclenché par des molécules élicitrices exogènes ou endogènes. Une autre classe d’éliciteurs, les éliciteurs synthétiques, contient également des composés promouvant une réponse défensive.Dans ce manuscrit, je décris la découverte et caractérisation d’une nouvelle famille de petits peptides endogènes potentiellement sécrétés(PROSCOOP), dont les membres incluent de petits peptides (SCOOP). Je démontre que les SCOOP sont impliqués dans les mécanismes de défense de la plante et le développement racinaire. Une variété de peptides SCOOP induit des réponses défensives de courtes et longues durées.De plus, des traitements avec le peptideSCOOP12 induisent une résistance à Pseudomonas syringae chez Arabidopsis.Dans la seconde partie de cette thèse, je démontre que le traitement des plantes avec un éliciteur synthétique peut mener à une mémoire transcriptionnelle à long terme, et que le challenge subséquent des plantes traitées par application d’un éliciteur exogène désactive cette mémoire transcriptionnelle. En conclusion, ma thèse présente (1) la diversité des fonctions que peuvent avoir ces éliciteurs et (2) l’impact sur les systèmes de défense de la plante et ses conséquences sur la mémoire et le développement de la plante
As sessile organism, plants have to react quickly and strongly with defense responses to repel any invading pathogen. The plant immune system can be triggered by exogenous or endogenous elicitor molecules. Another class of elicitors are defense promoting compounds which are also known as synthetic elicitors. Here I describe the discovery and characterization of a novel family of potentially secreted small endogenous peptides (PROSCOOP) which members harbor small peptides (SCOOPs). I show that the SCOOP family is involved in plant defense and root development. Various SCOOP peptides induce short- and long-term defense responses. Moreover, treatments with the SCOOP12 peptide induce the resistance against Pseudomonas syringae in Arabidopsis. In the second part of this thesis, I show that treatments with a synthetic elicitor can lead to long-term transcriptional memory and that subsequent challenging of such plants with an exogenous elicitor reverted this transcriptional memory. In conclusion, my thesis shows (1) how diverse the function of these elicitors can be and (2) the impact the plant defense system and its triggers have on plant development and memory