Changes in the Microbial Composition of the Rhizosphere of Hop Plants Affected by Verticillium Wilt Caused by .

Verticillium wilt is a devastating disease affecting many crops, including hops. This study aims to describe fungal and bacterial populations associated with bulk and rhizosphere soils in a hop field cultivated in Slovenia with the Celeia variety, which is highly susceptible to . As both healthy and diseased plants coexist in the same field, we focused this study on the detection of putative differences in the microbial communities associated with the two types of plants.

Optimization and Validation of Singleplex and Multiplex RT-qPCR for Detection of (CBCVd), (HLVd), and (HSVd) in Hops ().

Direct crop losses due to plant diseases and the measures used to control them have significant agricultural and economic impacts. The shift from diverse small-scale to large-scale genetically uniform monoculture production, along with agricultural intensification and climate change, has led to several known epidemics in man-made agroecosystems that have been rendered more vulnerable to pathogens. One such example is hop growing, which is threatened by highly aggressive hop viroids.

Novel Identification of the Collection of Pathogenic Fungal Species with the Development of Species-Specific SSR Markers.

The genus is a group of ascomycete fungi that includes several pathogenic plant species. In 2011, a new taxonomic classification, proposed by Inderbitzin and coworkers (2011), re-defined the genus as sensu stricto. The objective of our study was the re-classification of the fungal species held in the culture collection in the Slovenian Institute of Hop Research and Brewing in accordance with the newly established taxonomy.

Cytosine Methylation in Genomic DNA and Characterization of DNA Methylases and Demethylases and Their Expression Profiles in Viroid-Infected Hop Plants ( Var. 'Celeia').

Abiotic and biotic stresses can lead to changes in host DNA methylation, which in plants is also mediated by an RNA-directed DNA methylation mechanism. Infections with viroids have been shown to affect DNA methylation dynamics in different plant hosts. The aim of our research was to determine the content of 5-methylcytosine (5-mC) in genomic DNA at the whole genome level of hop plants ( Var.

Discovery of microRNA-like Small RNAs in Pathogenic Plant Fungus Using High-Throughput Sequencing and qPCR and RLM-RACE Validation.

() is one of the most problematic hop ( L.) pathogens, as the highly virulent fungal pathotypes cause severe annual yield losses due to infections of entire hop fields. In recent years, the RNA interference (RNAi) mechanism has become one of the main areas of focus in plant-fungal pathogen interaction studies and has been implicated as one of the major contributors to fungal pathogenicity.

Transformation of Seed Non-Transmissible Hop Viroids in Causes Distortions in Male Gametophyte Development.

Viroids are small, non-coding, parasitic RNAs that promote developmental distortions in sensitive plants. We analyzed pollen of after infection and/or ectopic transformation with cDNAs of citrus bark cracking viroid (CBCVd), apple fruit crinkle viroid (AFCVd) and potato spindle tuber viroid (PSTVd) variant AS1. These viroids were seed non-transmissible in .

Identification and Characterization of -Responsive MicroRNAs in the Roots of Resistant and Susceptible Hop Cultivars.

MicroRNAs are 21- to 24-nucleotide-long, non-coding RNA molecules that regulate gene expression at the post-transcriptional level. They can modulate various biological processes, including plant response and resistance to fungal pathogens. Hops are grown for use in the brewing industry and, recently, also for the pharmaceutical industry.

The hop downy mildew pathogen Pseudoperonospora humuli.

Unlabelled: Pseudoperonospora humuli is an obligate biotrophic oomycete that causes downy mildew, one of the most devastating diseases of cultivated hop, Humulus lupulus. Downy mildew occurs in all production areas of the crop in the Northern Hemisphere and Argentina. The pathogen overwinters in hop crowns and roots, and causes considerable crop loss.

Core RNA Interference Genes Involved in miRNA and Ta-siRNA Biogenesis in Hops and Their Expression Analysis after Challenging with .

RNA interference is an evolutionary conserved mechanism by which organisms regulate the expression of genes in a sequence-specific manner to modulate defense responses against various abiotic or biotic stresses. Hops are grown for their use in brewing and, in recent years, for the pharmaceutical industry. Hop production is threatened by many phytopathogens, of which , the causal agent of Verticillium wilt, is a major contributor to yield losses.

Hop Polyphenols in Relation to Verticillium Wilt Resistance and Their Antifungal Activity.

(1) Background: Verticillium wilt (VW) of hop is a devastating disease caused by the soil-borne fungi and . As suggested by quantitative trait locus (QTL) mapping and RNA-Seq analyses, the underlying molecular mechanisms of resistance in hop are complex, consisting of preformed and induced defense responses, including the synthesis of various phenolic compounds. (2) Methods: We determined the total polyphenolic content at two phenological stages in roots and stems of 14 hop varieties differing in VW resistance, examined the changes in the total polyphenols of VW resistant variety Wye Target (WT) and susceptible Celeia (CE) on infection with , and assessed the antifungal activity of six commercial phenolic compounds and total polyphenolic extracts from roots and stems of VW resistant WT and susceptible CE on the growth of two different hop pathotypes.

Changes in the Phenolic Compounds of Hop ( L.) Induced by Infection with , the Causal Agent of Hop Wilt.

Phenolic compounds are involved in plant responses to various biotic and abiotic stress factors, with many studies suggesting their role in defense mechanisms against fungal pathogens. Soilborne vascular pathogen causes severe wilting and consequent dieback in a wide range of economically important crops, including hops ( L.).

Mapping the Gene Expression Spectrum of Mediator Subunits in Response to Viroid Infection in Plants.

The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive.

Population Diversity and Structure of in the Pacific Northwestern United States and Other Populations.

Powdery mildew, caused by , is one of the most important diseases of hop. The disease was first reported in the Pacific Northwestern United States, the primary hop-growing region in this country, in the mid-1990s. More recently, the disease has reemerged in newly planted hopyards of the eastern United States, as hop production has expanded to meet demands of local craft brewers.

Temporal and spatial assessment of defence responses in resistant and susceptible hop cultivars during infection with Verticillium nonalfalfae.

Hop (Humulus lupulus L.) is an important industrial plant providing ingredients for brewing and pharmaceutical industry worldwide. Its intensive production is challenged by numerous diseases.

Evaluation of Disease Severity and Global Transcriptome Response Induced by , , and Their Co-Infection in Hop ( L.).

Viroids are small non-capsidated, single-stranded, covalently-closed circular noncoding RNA replicons of 239-401 nucleotides that exploit host factors for their replication, and some cause disease in several economically important crop plants, while others appear to be benign. The proposed mechanisms of viroid pathogenesis include direct interaction of the genomic viroid RNA with host factors and post-transcriptional or transcriptional gene silencing via viroid-derived small RNAs (vd-sRNAs) generated by the host defensive machinery. (hop) plants are hosts to several viroids among which (HLVd) and (CBCVd) are attractive model systems for the study of viroid-host interactions due to the symptomless infection of the former and severe symptoms induced by the latter in this indicator host.

RNA interference core components identified and characterised in Verticillium nonalfalfae, a vascular wilt pathogenic plant fungi of hops.

The conserved RNA interference mechanism (RNAi) in the fungal kingdom has become a focus of intense scientific investigation. The three catalytic core components, Dicer-like (DCL), Argonaute (AGO), and RNA-dependent RNA polymerase (RdRP), and their associated small interfering RNA molecules (siRNAs) have been identified and characterised in several fungal species. Recent studies have proposed that RNAi is a major contributor to the virulence of fungal pathogens as a result of so-called trans-kingdom RNA silencing.

Chitin-Binding Protein of Disguises Fungus from Plant Chitinases and Suppresses Chitin-Triggered Host Immunity.

During fungal infections, plant cells secrete chitinases, which digest chitin in the fungal cell walls. The recognition of released chitin oligomers via lysin motif (LysM)-containing immune host receptors results in the activation of defense signaling pathways. We report here that , a hemibiotrophic xylem-invading fungus, prevents these digestion and recognition processes by secreting a carbohydrate-binding motif 18 (CBM18)-chitin-binding protein, VnaChtBP, which is transcriptionally activated specifically during the parasitic life stages.

Viruses Associated with Fig Mosaic Disease in Different Fig Varieties in Montenegro.

Symptoms of fig mosaic disease have been noticed on leaves of fig () for several decades, in Montenegro. In 2014, leaf samples were collected from trees of six fig cultivars in a plantation located in the main fig-producing area of Montenegro, to study the disease. After RNA isolation, samples were tested by RT-PCR for detection of nine fig viruses and three viroids.

Comprehensive analysis of Verticillium nonalfalfae in silico secretome uncovers putative effector proteins expressed during hop invasion.

The vascular plant pathogen Verticillium nonalfalfae causes Verticillium wilt in several important crops. VnaSSP4.2 was recently discovered as a V.

Genome Sequence of a Lethal Strain of Xylem-Invading .

, a soilborne vascular phytopathogenic fungus, causes wilt disease in several crop species. Of great concern are outbreaks of highly aggressive strains, which cause a devastating wilt disease in European hops. We report here the genome sequence and annotation of strain T2, providing genomic information that will allow better understanding of the molecular mechanisms underlying the development of highly aggressive strains.

Development of hop transcriptome to support research into host-viroid interactions.

Viroids, the smallest known pathogens, unable to encode any proteins, can cause severe diseases in their host plants. One of the proposed mechanisms of their pathogenicity includes silencing the host's genes via viroid-derived small RNAs, which are products of the host's immune response to the viroid's double stranded RNA. Humulus lupulus (hop) plants are hosts to several viroids; two of them, HLVd and CBCVd, are interesting models for studying host-viroid interactions, due to the symptomless infection of the former and severe stunting disease caused by the latter.

Comparative transcriptional analysis of hop responses to infection with Verticillium nonalfalfae.

Dynamic transcriptome profiling revealed excessive, yet ineffective, immune response to V. nonalfalfae infection in susceptible hop, global gene downregulation in shoots of resistant hop and only a few infection-associated genes in roots. Hop (Humulus lupulus L.

Propagation and some physiological effects of Citrus bark cracking viroid and Apple fruit crinkle viroid in multiple infected hop (Humulus lupulus L.).

The hop metabolome important for the brewing industry and for medical purposes is endangered worldwide due to multiple viroid infections affecting hop physiology. Combinatorial biolistic hop inoculation with Citrus bark cracking viroid (CBCVd), Apple fruit crinkle viroid (AFCVd), Hop latent viroid, and Hop stunt viroid (HSVd) showed a low CBCVd compatibility with HSVd, while all other viroid combinations were highly compatible. Unlike to other viroids, single CBCVd propagation showed a significant excess of (-) over (+) strands in hop, tomato, and Nicotiana benthamiana, but not in citruses.

Xylem Sap Extraction Method from Hop Plants.

Verticillium wilt is one of the most important diseases on hop that significantly influence continuation of production on affected areas. It is caused by the soil borne vascular pathogen , which infects plants through the roots and then advances through the vascular (xylem) system. During infection, secretes many different virulence factors.