DspA/E-Triggered Non-Host Resistance against Depends on the Arabidopsis Gene.

DspA/E is a type three effector injected by the pathogenic bacterium inside plant cells. In non-host , DspA/E inhibits seed germination, root growth, de novo protein synthesis and triggers localized cell death. To better understand the mechanisms involved, we performed EMS mutagenesis on a transgenic line, 13-1-2, containing an inducible gene.

Plant nitrate supply regulates Erwinia amylovora virulence gene expression in Arabidopsis.

We showed previously that nitrogen (N) limitation decreases Arabidopsis resistance to Erwinia amylovora (Ea). We show that decreased resistance to bacteria in low N is correlated with lower apoplastic reactive oxygen species (ROS) accumulation and lower jasmonic acid (JA) pathway expression. Consistently, pretreatment with methyl jasmonate (Me-JA) increased the resistance of plants grown under low N.

LPMO-oxidized cellulose oligosaccharides evoke immunity in Arabidopsis conferring resistance towards necrotrophic fungus B. cinerea.

Lytic Polysaccharide Monooxygenases (LPMOs) are powerful redox enzymes able to oxidatively cleave recalcitrant polysaccharides. Widely conserved across biological kingdoms, LPMOs of the AA9 family are deployed by phytopathogens to deconstruct cellulose polymers. In response, plants have evolved sophisticated mechanisms to sense cell wall damage and thus self-triggering Damage Triggered Immunity responses.

Every cloud has a silver lining: how abiotic stresses affect gene expression in plant-pathogen interactions.

Current environmental and climate changes are having a pronounced influence on the outcome of plant-pathogen interactions, further highlighting the fact that abiotic stresses strongly affect biotic interactions at various levels. For instance, physiological parameters such as plant architecture and tissue organization together with primary and specialized metabolism are affected by environmental constraints, and these combine to make an individual plant either a more or less suitable host for a given pathogen. In addition, abiotic stresses can affect the timely expression of plant defense and pathogen virulence.

Plant nitrogen supply affects the Botrytis cinerea infection process and modulates known and novel virulence factors.

Plant nitrogen (N) fertilization is known to affect disease; however, the underlying mechanisms remain mostly unknown. We investigated the impact of N supply on the Arabidopsis thaliana-Botrytis cinerea interaction. A.

Post-flowering biotic and abiotic stresses impact nitrogen use efficiency and seed filling in Arabidopsis thaliana.

Nitrogen (N) is an essential nutrient that plants require for the synthesis of amino acids, proteins, and many other important metabolites. Plant metabolism and growth are consequently dependent on the amount of N that is assimilated and distributed from source leaves to developing sinks, such as fruits and seeds. The environmental stresses enhanced by climate change deeply influence seed yield and seed composition, and may disturb N use efficiency (NUE) in pants.

Oligogalacturonide production upon - interaction.

Despite an ever-increasing interest for the use of pectin-derived oligogalacturonides (OGs) as biological control agents in agriculture, very little information exists-mainly for technical reasons-on the nature and activity of the OGs that accumulate during pathogen infection. Here we developed a sensitive OG profiling method, which revealed unsuspected features of the OGs generated during infection of with the fungus Indeed, in contrast to previous reports, most OGs were acetyl- and methylesterified, and 80% of them were produced by fungal pectin lyases, not by polygalacturonases. Polygalacturonase products did not accumulate as larger size OGs but were converted into oxidized GalA dimers.

The SCOOP12 peptide regulates defense response and root elongation in Arabidopsis thaliana.

Small secreted peptides are important players in plant development and stress response. Using a targeted in silico approach, we identified a family of 14 Arabidopsis genes encoding precursors of serine-rich endogenous peptides (PROSCOOP). Transcriptomic analyses revealed that one member of this family, PROSCOOP12, is involved in processes linked to biotic and oxidative stress as well as root growth.

Nitrogen Limitation Alters the Response of Specific Genes to Biotic Stress.

In their natural environment, plants are generally confronted with multiple co-occurring stresses. However, the interaction between stresses is not well known and transcriptomic data in response to combined stresses remain scarce. This study aims at characterizing the interaction between transcriptomic responses to biotic stress and nitrogen (N) limitation.

Quantitative Methods to Assess Differential Susceptibility of Natural Accessions to .

Among the most devastating bacterial diseases of plants, provoked by 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 disease control approaches.

Dickeya dadantii pectic enzymes necessary for virulence are also responsible for activation of the Arabidopsis thaliana innate immune system.

Soft-rot diseases of plants attributed to Dickeya dadantii result from lysis of the plant cell wall caused by pectic enzymes released by the bacterial cell by a type II secretion system (T2SS). Arabidopsis thaliana can express several lines of defence against this bacterium. We employed bacterial mutants with defective envelope structures or secreted proteins to examine early plant defence reactions.

DspA/E Contributes to Apoplastic Accumulation of ROS in Non-host A. thaliana.

The bacterium Erwinia amylovora is responsible for the fire blight disease of Maleae, which provokes necrotic symptoms on aerial parts. The pathogenicity of this bacterium in hosts relies on its type three-secretion system (T3SS), a molecular syringe that allows the bacterium to inject effectors into the plant cell. E.

The bile acid deoxycholate elicits defences in Arabidopsis and reduces bacterial infection.

Disease has an effect on crop yields, causing significant losses. As the worldwide demand for agricultural products increases, there is a need to pursue the development of new methods to protect crops from disease. One mechanism of plant protection is through the activation of the plant immune system.

Nitrogen metabolism meets phytopathology.

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 streams, groundwater, and lakes, where it affects algal production and causes an imbalance in aquatic food webs.

The hnRNP-Q protein LIF2 participates in the plant immune response.

Eukaryotes have evolved complex defense pathways to combat invading pathogens. Here, we investigated the role of the Arabidopsis thaliana heterogeneous nuclear ribonucleoprotein (hnRNP-Q) LIF2 in the plant innate immune response. We show that LIF2 loss-of-function in A.

The bacterial effector DspA/E is toxic in Arabidopsis thaliana and is required for multiplication and survival of fire blight pathogen.

The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium Erwinia amylovora. We showed that DspA/E was required for transient bacterial growth in nonhost Arabidopsis thaliana leaves, as an E. amylovora dspA/E mutant was unable to grow.

Characterization of the Nrt2.6 gene in Arabidopsis thaliana: a link with plant response to biotic and abiotic stress.

The high affinity nitrate transport system in Arabidopsis thaliana involves one gene and potentially seven genes from the NRT1 and NRT2 family, respectively. Among them, NRT2.1, NRT2.

EDS1 contributes to nonhost resistance of Arabidopsis thaliana against Erwinia amylovora.

Erwinia amylovora causes fire blight in rosaceous plants. In nonhost Arabidopsis thaliana, E. amylovora triggers necrotic symptoms associated with transient bacterial multiplication, suggesting either that A.

Expressing the Erwinia amylovora type III effector DspA/E in the yeast Saccharomyces cerevisiae strongly alters cellular trafficking.

Erwinia amylovora is responsible for fire blight, a necrotic disease of apples and pears. E. amylovora relies on a type III secretion system (T3SS) to induce disease on host plants.

The HrpN effector of Erwinia amylovora, which is involved in type III translocation, contributes directly or indirectly to callose elicitation on apple leaves.

Erwinia amylovora is responsible for fire blight of apple and pear trees. Its pathogenicity depends on a type III secretion system (T3SS) mediating the translocation of effectors into the plant cell. The DspA/E effector suppresses callose deposition on apple leaves.

Microbial siderophores exert a subtle role in Arabidopsis during infection by manipulating the immune response and the iron status.

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 up-regulation of the plant ferritin gene AtFER1.

Arabidopsis thaliana expresses multiple lines of defense to counterattack Erwinia chrysanthemi.

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 plants respond to E.

Changes in transcriptional profiles are associated with early fruit tissue specialization in tomato.

The cell expansion phase contributes in determining the major characteristics of a fleshy fruit and represents two-thirds of the total fruit development in tomato (Solanum lycopersicum). So far, it has received very little attention. To evaluate the interest of a genomic scale approach, we performed an initial sequencing of approximately 1,200 cell expansion stage-related sequence tags from tomato fruit at 8, 12, and 15 d post anthesis.

The Arabidopsis HOMOLOGY-DEPENDENT GENE SILENCING1 gene codes for an S-adenosyl-L-homocysteine hydrolase required for DNA methylation-dependent gene silencing.

Genes introduced into higher plant genomes can become silent (gene silencing) and/or cause silencing of homologous genes at unlinked sites (homology-dependent gene silencing or HDG silencing). Mutations of the HOMOLOGY-DEPENDENT GENE SILENCING1 (HOG1) locus relieve transcriptional gene silencing and methylation-dependent HDG silencing and result in genome-wide demethylation. The hog1 mutant plants also grow slowly and have low fertility and reduced seed germination.

Arabidopsis histone deacetylase HDA6 is required for maintenance of transcriptional gene silencing and determines nuclear organization of rDNA repeats.

Histone acetylation and deacetylation are connected with transcriptional activation and silencing in many eukaryotic organisms. Gene families for enzymes that accomplish these modifications show a surprising multiplicity in sequence and expression levels, suggesting a high specificity for different targets. We show that mutations in Arabidopsis (Arabidopsis thaliana) HDA6, a putative class I histone deacetylase gene, result in loss of transcriptional silencing from several repetitive transgenic and endogenous templates.