Inoculation and Propagation Modify the Xylem Microbiome and Disease Reaction to Verticillium Wilt in a Wild Olive Genotype.

Host resistance is the most practical, long-term, and economically efficient disease control measure for Verticillium wilt in olive caused by the xylem-invading fungus (), and it is at the core of the integrated disease management. Plant's microbiome at the site of infection may have an influence on the host reaction to pathogens; however, the role of xylem microbial communities in the olive resistance to has been overlooked and remains unexplored to date. This research was focused on elucidating whether olive propagation may alter the diversity and composition of the xylem-inhabiting microbiome and if those changes may modify the resistance response that a wild olive clone shows to the highly virulent defoliating (D) pathotype of .

Heterologous Expression of the Gene in Olive and Its Effects on Fungal Tolerance.

The gene encodes a key component of systemic acquired resistance (SAR) signaling mediated by salicylic acid (SA). Overexpression of confers resistance to biotrophic and hemibiotrophic fungi in several plant species. The gene has also been shown to be involved in the crosstalk between SAR signaling and the jasmonic acid-ethylene (JA/Et) pathway, which is involved in the response to necrotrophic fungi.

Plant Regeneration Somatic Embryogenesis in Mature Wild Olive Genotypes Resistant to the Defoliating Pathotype of .

Regeneration capacity, somatic embryogenesis, of four wild olive genotypes differing in their response to defoliating (resistant genotypes StopVert, OutVert, Ac-18 and the susceptible one, Ac-15) has been evaluated. To induce somatic embryogenesis, methodologies previously used in wild or cultivated olive were used. Results revealed the importance of genotype, explant type, and hormonal balance in the induction process.

Transcriptomic Analysis of Overgrowing Plant-Wilting Reveals the Role of a New M14 Metallocarboxypeptidase CPA1 in Biocontrol.

, a vascular-colonizing fungus, causes economically important wilt diseases in many crops, including olive trees. spp. have demonstrated an effective contribution as biocontrol agents against this pathogen through a variety of mechanisms that may involve direct mycoparasitism and antibiosis.

Usage of the Heterologous Expression of the Antimicrobial Gene From for Increasing Fungal Resistance in Olive.

The antifungal protein (AFP) produced by , encoded by the gene, has been used to confer resistance against a broad range of fungal pathogens in several crops. In this research, transgenic olive plants expressing the gene under the control of the constitutive promoter CaMV35S were generated and their disease response against two root infecting fungal pathogens, and , was evaluated. Embryogenic cultures derived from a mature zygotic embryo of cv.

Clonal Expansion and Migration of a Highly Virulent, Defoliating Lineage of Verticillium dahliae.

We used a population genomics approach to test the hypothesis of clonal expansion of a highly fit genotype in populations of Verticillium dahliae. This fungal pathogen has a broad host range and can be dispersed in contaminated seed or other plant material. It has a highly clonal population structure, with several lineages having nearly worldwide distributions in agricultural crops.

Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants.

Two haplotypes of Xylella fastidiosa subsp. pauca (Xfp) that correlated with their host of origin were identified in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the gyrB sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of Xfp according to the host source.

Symptomless Host and Nonhost Responses of Paulownia (Paulownia spp.) to Olive-Defoliating Verticillium dahliae.

Symptomless host and nonhost responses of Paulownia spp. to olive-defoliating (D) Verticillium dahliae is reported for the first time. Two paulownia clones, Paulownia elongata 'PC-2' and P.

Recombination between clonal lineages of the asexual fungus Verticillium dahliae detected by genotyping by sequencing.

Most asexual species of fungi have either lost sexuality recently, or they experience recombination by cryptic sexual reproduction. Verticillium dahliae is a plant-pathogenic, ascomycete fungus with no known sexual stage, even though related genera have well-described sexual reproduction. V.

Complex molecular relationship between vegetative compatibility groups (VCGs) in Verticillium dahliae: VCGs do not always align with clonal lineages.

Verticillium wilts caused by the soilborne fungus Verticillium dahliae are among the most challenging diseases to control. Populations of this pathogen have been traditionally studied by means of vegetative compatibility groups (VCGs) under the assumption that VCGs comprise genetically related isolates that correlate with clonal lineages. We aimed to resolve the phylogenetic relationships among VCGs and their subgroups based on sequences of the intergenic spacer region (IGS) of the ribosomal DNA and six anonymous polymorphic sequences containing single-nucleotide polymorphisms (VdSNPs).

Quantitative and microscopic assessment of compatible and incompatible interactions between chickpea cultivars and Fusarium oxysporum f. sp. ciceris races.

Background: Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris, a main threat to global chickpea production, is managed mainly by resistant cultivars whose efficiency is curtailed by Fusarium oxysporum f.

Molecular and Pathogenic Characterization of Fusarium redolens, a New Causal Agent of Fusarium Yellows in Chickpea.

The association of Fusarium redolens with wilting-like symptoms in chickpea in Lebanon, Morocco, Pakistan, and Spain is reported for the first time, together with the molecular and pathogenic characterization of isolates of the pathogen from chickpea of diverse geographic origin. Maximum parsimony analysis of sequences of the translation elongation factor 1α (TEF-1α) gene grouped all F. redolens isolates from chickpea in the same main clade.

A proteomic study of in-root interactions between chickpea pathogens: the root-knot nematode Meloidogyne artiellia and the soil-borne fungus Fusarium oxysporum f. sp. ciceris race 5.

Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. ciceris (Foc) is the main soil-borne disease limiting chickpea production.

Real-Time PCR Quantification of Peronospora arborescens, the Opium Poppy Downy Mildew Pathogen, in Seed Stocks and Symptomless Infected Plants.

In this study, we developed a reliable, quick, and accurate quantitative polymerase chain reaction (qPCR) assay based on the MIQE (Minimum Information for publication of Quantitative Real-Time PCR Experiments) guidelines for the quantification of Peronospora arborescens in infected downy mildew-symptomless opium poppy (Papaver somniferum) tissues and commercial seed stocks. The protocol was highly reproducible and allowed accurate quantification of pathogen DNA up to 10 fg in different plant DNA backgrounds without losing specificity and efficiency. Moreover, to further overcome difficulties conferred by the strict biotrophy of this pathogen, we developed dilution series of DNA extracted from a plasmid with the target pathogen DNA as a cloned insert.

In planta and soil quantification of Fusarium oxysporum f. sp. ciceris and evaluation of Fusarium wilt resistance in chickpea with a newly developed quantitative polymerase chain reaction assay.

Fusarium wilt of chickpea caused by Fusarium oxysporum f. sp. ciceris can be managed by risk assessment and use of resistant cultivars.

DNA sequence analysis of conserved genes reveals hybridization events that increase genetic diversity in Verticillium dahliae.

The hybrid origin of a Verticillium dahliae isolate belonging to the vegetative compatibility group (VCG) 3 is reported in this work. Moreover, new data supporting the hybrid origin of two V. dahliae var.

Region-wide analysis of genetic diversity in Verticillium dahliae populations infecting olive in southern Spain and agricultural factors influencing the distribution and prevalence of vegetative compatibility groups and pathotypes.

Severity of Verticillium wilt in olive trees in Andalusia, southern Spain is associated with the spread of a highly virulent, defoliating (D) Verticillium dahliae pathotype of vegetative compatibility group 1A (VCG1A) but the extent of this spread and the diversity of the pathogen population have never been documented. VCG typing of 637 V. dahliae isolates from 433 trees in 65 orchards from five olive-growing provinces in Andalusia indicated that 78.

Verticillium Wilt: A Threat to Artichoke Production.

Verticillium wilt is becoming an increasing concern in artichoke production because the rapid spread of the disease to new growing areas has led to declining production. Scientists from Italy, Spain, and the United States combine to bring us up to date on diagnosis of the disease, its epidemiology and life cycle, as well as management strategies, current and forthcoming.

A nested-polymerase chain reaction protocol for detection and population biology studies of Peronospora arborescens, the downy mildew pathogen of opium poppy, using herbarium specimens and asymptomatic, fresh plant tissues.

A sensitive nested-polymerase chain reaction (PCR) protocol was developed using either of two primer pairs that improves the in planta detection of Peronospora arborescens DNA. The new protocol represented an increase in sensitivity of 100- to 1,000-fold of detection of the oomycete in opium poppy tissue compared with the detection limit of single PCR using the same primer pairs. The new protocol allowed amplification of 5 to 0.

Genetic and Virulence Diversity in Verticillium dahliae Populations Infecting Artichoke in Eastern-Central Spain.

ABSTRACT Severe Verticillium dahliae attacks have occurred in artichoke crops in the Comunidad Valenciana region of eastern-central Spain since the late 1990s. Knowledge of genetic and virulence diversity in the pathogen population is a key factor for the management of the disease through disease risk assessment as well as development and use of resistant cultivars. V.

Molecular Variability Within and Among Verticillium dahliae Vegetative Compatibility Groups Determined by Fluorescent Amplified Fragment Length Polymorphism and Polymerase Chain Reaction Markers.

ABSTRACT A degree of genetic diversity may exist among Verticillium dahliae isolates within vegetative compatibility groups (VCGs) that bears phytopathological significance and is worth investigating using molecular tools of a higher resolution than VCG characterization. The molecular variability within and among V. dahliae VCGs was studied using 53 artichoke isolates from eastern-central Spain, 96 isolates from cotton, 7 from cotton soil, and 45 from olive trees in countries of the Mediterranean Basin.

Stepwise Evolution of Races in Fusarium oxysporum f. sp. ciceris Inferred from Fingerprinting with Repetitive DNA Sequences.

ABSTRACT Plant pathogens often exhibit variation in virulence, the ability to cause disease on host plants with specific resistance, evident from the diversity of races observed within pathogen species. The evolution of races in asexual fungal pathogens has been hypothesized to occur in a stepwise fashion, in which mutations to virulence accumulate sequentially in clonal lineages, resulting in races capable of overcoming multiple host plant resistance genes or multiple resistant cultivars. In this study, we demonstrate a simple stepwise pattern of race evolution in Fusarium oxysporum f.

Interactions Between Meloidogyne artiellia, the Cereal and Legume Root-Knot Nematode, and Fusarium oxysporum f. sp. ciceris Race 5 in Chickpea.

ABSTRACT In the Mediterranean Basin, Fusarium oxysporum f. sp. ciceris and the root-knot nematode Meloidogyne artiellia coinfect chickpea.