Alia Dellagi

AgroParisTech · Life and Health Scence

[This corrects the article DOI: 10.3389/fpls.2021.807798.].

Owing to the large genetic diversity of barley and its resilience under harsh environments, this crop is of great value for agroecological transition and the need for reduction of nitrogen (N) fertilizers inputs. In the present work, we investigated the diversity of a North African barley genotype collection in terms of growth under limiting N (LN)...

Autophagy is a ubiquitous vesicular process for protein and organelle recycling in eukaryotes. In plant, autophagy is reported to play pivotal roles in nutrient recycling, adaptation to biotic and abiotic stresses. The role of autophagy in plant immunity remains poorly understood. Several reports showed enhanced susceptibility of different Arabidop...

Plant defense stimulators, used in crop protection, are an attractive option to reduce the use of conventional crop protection products and optimize biocontrol strategies. These products are able to activate plant defenses and thus limit infection by pathogens. However, the effectiveness of these plant defense stimulators remains erratic and is pot...

Nitrogen (N) is an essential element for plant productivity, thus, it is abundantly applied to the soil in the form of organic or chemical fertilizers that have negative impacts on the environment. Exploiting the potential of beneficial microbes and identifying crop genotypes that can capitalize on symbiotic associations may be possible ways to sig...

Nitrogen (N) is an essential element for plant productivity, thus, it is abundantly applied to the soil in the form of organic or chemical fertilizers that have negative impacts on the environment. Exploiting the potential of beneficial microbes and identifying crop genotypes that can capitalize on symbiotic associations may be possible ways to sig...

Few secreted proteins involved in plant infection common to necrotrophic bacteria, fungi and oomycetes have been identified except for plant cell wall-degrading enzymes. Here we study a family of iron-binding proteins that is present in Gram-negative and Gram-positive bacteria, fungi, oomycetes and some animals. Homolog proteins in the phytopathoge...

Among the most devastating bacterial diseases of plants, soft rot provoked by Dickeya spp. cause crop yield losses on a large range of species with potato being the most economically important. The use of antibiotics being prohibited in most countries in the field, identifying tolerance genes is expected to be one of the most effective alternate di...

Microorganisms use siderophores to obtain iron from the environment. In pathogenic interactions, siderophores are involved in iron acquisition from the host and are sometimes necessary for the expression of full virulence. This review summarizes the main data describing the role of these iron scavengers in animal and plant defence systems. To prote...

Considering the Ecophyto 2018 directives, the development of molecules able to stimulate the natural defenses of plants (SDP) is a booming and promising strategy. However, the effectiveness of the SDP remains uncertain and there are no efficient diagnostic tools to assess their activation capacity in the field. The objective of this project is to d...

Dickeya dadantii is a plant pathogenic enterobacterium responsible for plant soft rot disease in a wide range of hosts including the model plant Arabidopsis thaliana. Iron distribution in infected A. thaliana was investigated at the cellular scale using the Perls′ –diaminobenzidine- H2O2 method. Iron visualization during infection reveals a loss of...

Nitrogen (N) is essential for life and is a major limiting factor of plant growth. Because soils frequently lack sufficient N, large quantities of inorganic N fertilizers are added to soils for crop production. However, nitrate, urea, and ammonium are a major source of global pollution, because much of the N that is not taken up by plants enters st...

Multigenic families of Plant Defensin type 1 (PDF1) have been described in several species, including the model plant Arabidopsis thaliana as well as zinc tolerant and hyperaccumulator A. halleri. In A. thaliana, PDF1 transcripts (AtPDF1) accumulate in response to pathogen attack following synergic activation of ethylene/jasmonate pathways. However...

Siderophores are specific ferric iron chelators synthesized by virtually all micro-organisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora Siderophores have also the ability to activate plant immunity. We have used CATMA microarrays t...

Infectious diseases are the result of competitive relationships between a host organism and a pathogen. In host vertebrate–microbe interactions, the acquisition of iron for the essential metabolism of pathogenic organisms and the need of the host to bind and sequestrate the metal are central issues. Plants are also confronted with a wide variety of...

Iron is an essential element for most living organisms, and pathogens are likely to compete with their hosts for the acquisition of this element. The bacterial plant pathogen Dickeya dadantii has been shown to require its siderophore-mediated iron uptake system for systemic disease progression on several host plants, including Arabidopsis thaliana....

Siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. The pathogenic enterobacterium Erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (CB), which are required for systemic dissemination in host plants. Previous studies have shown that CB is produced in planta and can trigger the...

AtNRAMP3 and AtNRAMP4 are two Arabidopsis metal transporters sharing about 50% sequence identity with mouse NRAMP1. The NRAMP1/Slc11A1 metal ion transporter plays a crucial role in the innate immunity of animal macrophages targeted by intracellular bacterial pathogens. AtNRAMP3 and AtNRAMP4 localize to the vacuolar membrane. We found that AtNRAMP3...

Many taxonomically diverse plant species are attacked by Erwinia chrysanthemi, a member of the causal agents of soft-rotting diseases. Symptom development is due to the collective action of pectin-degrading enzymes secreted by the bacterium through a type II secretion system (T2SS). Using Arabidopsis thaliana as a susceptible host, we show that pla...

The enterobacterial pathogen Erwinia chrysanthemi causes soft rot diseases on a wide range of plants, including the model plant Arabidopsis thaliana. This bacterium proliferates in the host by secreting a set of pectin degrading enzymes responsible for symptom development. In addition, survival of this bacterium in planta requires two high-affinity...

Ferritins are multimeric iron storage proteins encoded by a four-member gene family in Arabidopsis (AtFer1-4). To investigate whether iron sequestration in ferritins is a part of an iron-withholding defense system induced in response to bacterial invasion, we used Arabidopsis thaliana as a susceptible host for the pathogenic bacterium Erwinia chrys...

A potato gene encoding a putative WRKY protein was isolated from a cDNA library enriched by suppression subtractive hybridization for sequences upregulated 1 h postinoculation with Erwinia carotovora subsp. atroseptica. The cDNA encodes a putative polypeptide of 172 amino acids, containing a single WRKY domain with a zinc finger motif and preceded...

A polymerase chain reaction-based method has been developed for quantitative detection of Erwinia carotovora subsp. atroseptica on potato tubers. It uses a competitor template cloned into Escherichia coli added to the test tuber-peel extract to both detect and quantify E. c. atroseptica.

A potato gene, erg-1, was isolated from a cDNA library enriched by suppression subtractive hybridisation for sequences up-regulated one hour after inoculation of cv. Stirling leaves with Erwinia carotovora ssp. atroseptica (Eca). Erg-1 (Eca response gene 1) exhibits strong similarity to phi-1, previously reported to be up-regulated by addition of p...

A PCR-based method was developed for the simultaneous detection and quantification of the potato pathogen Erwinia carotovora subsp. atroseptica (Eca) on potato tubers. The method incorporates a competitor PCR template cloned into Escherichia coli in vector pGEM-T (E. coli 4R l/l). Predetermined numbers of E. coli 4R were added to potato peel extrac...

For studies of differential gene expression in prokaryotes, methods for synthesizing representative cDNA populations are required. Here, a technique is described for the synthesis of cDNA from the potato pathogens Erwinia carotovora subsp. atroseptica (Eca) and Erwinia carotovora subsp. carotovora (Ecc) using a combination of short oligonucleotide...

This book is the first multi-authored book on fire blight, the most devastating bacterial disease of apples and pears. It is divided into three sections. The first section is about the disease: its epidemiology, its worldwide distribution and its economic importance, the host range of the pathogen and how it migrates and survives in the fruit tissu...

Mutants of Erwinia amylovora CFBP 1430 lacking a functional high-affinity iron transport system mediated by desferrioxamine are impaired in their ability to initiate fire blight symptoms (A. Dellagi, M.-N. Brisset, J.-P. Paulin, and D. Expert. Mol. Plant-Microbe Interact. 11:734-742, 1998). In this study, a chromosomal transcriptional lacZ fusion w...

To investigate the role of iron in Erwinia amylovora pathogenicity, virulence properties of two mutants of strain CFBP 1430 isolated by insertional mutagenesis and affected in the iron transport pathway mediated by desferrioxamine (DFO) were analyzed. One mutation (dfoA::MudIIpR13) disrupts DFO biosynthesis. The present analysis shows that this mut...

Iron deprivation of Erwinia amylovora CFBP1430, a species causing fire blight on Pomoïdeae, was shown to induce the production of siderophores of the desferrioxamine (dfo) family and two outer membrane polypeptides with apparent molecular weight of about 70 and 80 kDa, respectively. Cyclic dfo E was characterized as the major metabolite. Phage MudI...