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.

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.

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.

Genome-wide analyses of chitin synthases identify horizontal gene transfers towards bacteria and allow a robust and unifying classification into fungi.

Background: Chitin, the second most abundant biopolymer on earth after cellulose, is found in probably all fungi, many animals (mainly invertebrates), several protists and a few algae, playing an essential role in the development of many of them. This polysaccharide is produced by type 2 glycosyltransferases, called chitin synthases (CHS). There are several contradictory classifications of CHS isoenzymes and, as regards their evolutionary history, their origin and diversity is still a matter of debate.

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.

Evolutionary tinkering of the expression of PDF1s suggests their joint effect on zinc tolerance and the response to pathogen attack.

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.

Discovery of two new inhibitors of Botrytis cinerea chitin synthase by a chemical library screening.

Chitin synthases polymerize UDP-GlcNAC to form chitin polymer, a key component of fungal cell wall biosynthesis. Furthermore, chitin synthases are desirable targets for fungicides since chitin is absent in plants and mammals. Two potent Botrytis cinerea chitin synthase inhibitors, 2,3,5-tri-O-benzyl-d-ribose (compound 1) and a 2,5-functionalized imidazole (compound 2) were identified by screening a chemical library.

Disruption of Bcchs4, Bcchs6 or Bcchs7 chitin synthase genes in Botrytis cinerea and the essential role of class VI chitin synthase (Bcchs6).

Chitin synthases play critical roles in hyphal development and fungal pathogenicity. Previous studies on Botrytis cinerea, a model organism for necrotrophic pathogens, have shown that disruption of Bcchs1 and more particularly Bcchs3a genes have a drastic impact on virulence (Soulié et al., 2003, 2006).

Iron deficiency affects plant defence responses and confers resistance to Dickeya dadantii and Botrytis cinerea.

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. In this study, we investigated the effect of the iron status of Arabidopsis on the severity of disease caused by D.

The osmosensing signal transduction pathway from Botrytis cinerea regulates cell wall integrity and MAP kinase pathways control melanin biosynthesis with influence of light.

Mitogen activated protein kinase (MAPK) signal transduction pathways are ubiquitous among eukaryotic organisms with evolutionary conserved modules. Although generally classified as osmotic and cell wall integrity pathways, functional divergences have been observed for HOG1- and SLT2-related MAPK pathways. Here we show that the osmotic signal transduction cascade is involved in cell wall integrity in the phytopathogenic ascomycete Botrytis cinerea.

Disruption of the Bcchs3a chitin synthase gene in Botrytis cinerea is responsible for altered adhesion and overstimulation of host plant immunity.

The fungal cell wall is a dynamic structure that protects the cell from different environmental stresses suggesting that wall synthesizing enzymes are of great importance for fungal virulence. Previously, we reported the isolation and characterization of a mutant in class III chitin synthase, Bcchs3a, in the phytopathogenic fungus Botrytis cinerea. We demonstrated that virulence of this mutant is severely impaired.

Botrytis cinerea virulence is drastically reduced after disruption of chitin synthase class III gene (Bcchs3a).

Botrytis cinerea is an important phytopathogenic fungus requiring new methods of control. Chitin biosynthesis, which involves seven classes of chitin synthases, could be an attractive target. A fragment encoding one of the class III enzymes was used to disrupt the corresponding Bcchs3a gene in the B.

Survey of the Botrytis cinerea chitin synthase multigenic family through the analysis of six euascomycetes genomes.

We describe a strategy for systematic amplification of chitin synthase genes (chs) in the filamentous ascomycetes plant-pathogen Botrytis cinerea using PCR with multiple degenerate primers designed on specific and conserved sequence motifs. Eight distinct chs genes were isolated, named Bcchs I, II, IIIa, IIIb, IV, V, VI and VII. They probably constitute the entire chs multigenic family of this fungus, as revealed by careful analysis of six euascomycetes genomes.