Publications by authors named "Nicolas W G Chen"

Common bacterial blight of bean (CBB) is a devastating seed-transmitted disease caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans on common bean (Phaseolus vulgaris L.

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Although seed represents an important means of plant pathogen dispersion, the seed-pathogen dialogue remains largely unexplored. A multiomic approach was performed at different seed developmental stages of common bean (Phaseolus vulgaris L.) during asymptomatic colonization by Xanthomonas citri pv.

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Common bean ( L.) is the most important grain legume for direct human consumption worldwide. Flageolet bean originates from France and presents typical organoleptic properties, including the remarkable feature of having small pale green colored seeds.

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We report the complete and circularized genome sequences of nine strains of Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans, which cause common bacterial blight of bean.

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We report the complete and circularized genome sequences of 17 strains of Xanthomonas citri pv. fuscans and Xanthomonas phaseoli pv. phaseoli, which cause common bacterial blight of bean.

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We report the complete and circularized genome sequences of two strains of Xanthomonas citri pv. glycines causing bacterial pustule on soybean and one strain of Xanthomonas euvesicatoria pv. alfalfae causing bacterial leaf and stem spot on alfalfa.

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Accurate assessment of plant symptoms plays a key role for measuring the impact of pathogens during plant-pathogen interaction. Common bacterial blight caused by pv. and pv.

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Background: Xanthomonas citri pv. fuscans (Xcf) and Xanthomonas phaseoli pv. phaseoli (Xpp) are the causal agents of common bacterial blight of bean (CBB), an important disease worldwide that remains difficult to control.

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Background: Common bacterial blight (CBB) caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans is one of the major threats to common bean crops (Phaseolus vulgaris L.

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Subtelomeres of most eukaryotes contain fast-evolving genes usually involved in adaptive processes. In common bean (), the anthracnose resistance () locus corresponds to a cluster of nucleotide-binding-site leucine-rich-repeat (NL) encoding sequences, the prevalent class of plant genes. To study the recent evolution of this gene cluster, we used a combination of sequence, genetic and cytogenetic comparative analyses between common bean genotypes from two distinct gene pools (Andean and Mesoamerican) that diverged 0.

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Background: Host specialization is a hallmark of numerous plant pathogens including bacteria, fungi, oomycetes and viruses. Yet, the molecular and evolutionary bases of host specificity are poorly understood. In some cases, pathological convergence is observed for individuals belonging to distant phylogenetic clades.

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Background: Common bacterial blight is a devastating bacterial disease of common bean (Phaseolus vulgaris) caused by Xanthomonas citri pv. fuscans and Xanthomonas phaseoli pv. phaseoli.

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How pathogens coevolve with and adapt to their hosts are critical to understanding how host jumps and/or acquisition of novel traits can lead to new disease emergences. The Xanthomonas genus includes Gram-negative plant-pathogenic bacteria that collectively infect a broad range of crops and wild plant species. However, individual Xanthomonas strains usually cause disease on only a few plant species and are highly adapted to their hosts, making them pertinent models to study host specificity.

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Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species.

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

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Subtelomeric regions in eukaryotic organisms are known for harboring species-specific tandemly repeated satellite sequences. However, studies on the molecular organization and evolution of subtelomeric repeats are scarce, especially in plants. Khipu is a satellite DNA of 528-bp repeat unit, specific of the Phaseolus genus, with a subtelomeric distribution in common bean, P.

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In higher eukaryotes, centromeres are typically composed of megabase-sized arrays of satellite repeats that evolve rapidly and homogenize within a species' genome. Despite the importance of centromeres, our knowledge is limited to a few model species. We conducted a comprehensive analysis of common bean (Phaseolus vulgaris) centromeric satellite DNA using genomic data, fluorescence in situ hybridization (FISH), immunofluorescence and chromatin immunoprecipitation (ChIP).

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We used a comparative genomics approach to investigate the evolution of a complex nucleotide-binding (NB)-leucine-rich repeat (LRR) gene cluster found in soybean (Glycine max) and common bean (Phaseolus vulgaris) that is associated with several disease resistance (R) genes of known function, including Rpg1b (for Resistance to Pseudomonas glycinea1b), an R gene effective against specific races of bacterial blight. Analysis of domains revealed that the amino-terminal coiled-coil (CC) domain, central nucleotide-binding domain (NB-ARC [for APAF1, Resistance genes, and CED4]), and carboxyl-terminal LRR domain have undergone distinct evolutionary paths. Sequence exchanges within the NB-ARC domain were rare.

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*In plants, the evolution of specific resistance is poorly understood. Pseudomonas syringae effectors AvrB and AvrRpm1 are recognized by phylogenetically distinct resistance (R) proteins in Arabidopsis thaliana (Brassicaceae) and soybean (Glycine max, Fabaceae). In soybean, these resistances are encoded by two tightly linked R genes, Rpg1-b and Rpg1-r.

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The B4 resistance (R) gene cluster is one of the largest clusters known in common bean (Phaseolus vulgaris [Pv]). It is located in a peculiar genomic environment in the subtelomeric region of the short arm of chromosome 4, adjacent to two heterochromatic blocks (knobs). We sequenced 650 kb spanning this locus and annotated 97 genes, 26 of which correspond to Coiled-Coil-Nucleotide-Binding-Site-Leucine-Rich-Repeat (CNL).

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Retrotransposons and their remnants often constitute more than 50% of higher plant genomes. Although extensively studied in monocot crops such as maize (Zea mays) and rice (Oryza sativa), the impact of retrotransposons on dicot crop genomes is not well documented. Here, we present an analysis of retrotransposons in soybean (Glycine max).

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The genomes of most, if not all, flowering plants have undergone whole genome duplication events during their evolution. The impact of such polyploidy events is poorly understood, as is the fate of most duplicated genes. We sequenced an approximately 1 million-bp region in soybean (Glycine max) centered on the Rpg1-b disease resistance gene and compared this region with a region duplicated 10 to 14 million years ago.

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