Genomic-Assisted Marker Development Suitable for CsCvy-1 Selection in Cucumber Breeding

Cucumber is a widely grown vegetable crop plant and a host to many different plant pathogens. Cucumber vein yellowing virus (CVYV) causes economic losses on cucumber crops in Mediterranean countries and in some part of India such as West Bengal and in African countries such as Sudan. CVYV is an RNA potyvirus transmitted mechanically and by whitefly (Bemisia tabaci) in a semipersistent manner. Control of this virus is heavily dependent on the management of the insect vector and breeding virus-resistant lines. DNA markers have been used widely in conventional plant breeding programs via marker-assisted selection (MAS). However, very few resistance sources against CVYV in cucumber exist, and also the lack of tightly linked molecular markers to these sources restricts the rapid generation of resistant lines. In this work, we used genomics coupled with the bulked segregant analysis method and generated the MAS-friendly Kompetitive allele specific PCR (KASP) markers suitable for CsCvy-1 selection in cucumber breeding using a segregating F2 mapping population and commercial plant lines. Variant analysis was performed to generate single-nucleotide polymorphism (SNP)-based markers for mapping the population and genotyping the commercial lines. We fine-mapped the region by generating new markers down to 101 kb with eight genes. We provided SNP data for this interval, which could be useful for breeding programs and cloning the candidate genes.

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Semi-Automatic Method for Early Detection of Xylella fastidiosa in Olive Trees Using UAV Multispectral Imagery and Geostatistical-Discriminant Analysis

Remote Sensing ◽

10.3390/rs13010014 ◽

2020 ◽

Vol 13 (1) ◽

pp. 14

Author(s):

Annamaria Castrignanò ◽

Antonella Belmonte ◽

Ilaria Antelmi ◽

Ruggiero Quarto ◽

Francesco Quarto ◽

...

Keyword(s):

Discriminant Analysis ◽

Early Detection ◽

Plant Pathogens ◽

Early Stage ◽

Xylella Fastidiosa ◽

Mediterranean Countries ◽

Parametric Classification ◽

Aerial Vehicle ◽

Olive Groves ◽

Olive Trees

Xylella fastidiosa subsp. pauca (Xfp) is one of the most dangerous plant pathogens in the world. Identified in 2013 in olive trees in south–eastern Italy, it is spreading to the Mediterranean countries. The bacterium is transmitted by insects that feed on sap, and causes rapid wilting in olive trees. The paper explores the use of Unmanned Aerial Vehicle (UAV) in combination with a multispectral radiometer for early detection of infection. The study was carried out in three olive groves in the Apulia region (Italy) and involved four drone flights from 2017 to 2019. To classify Xfp severity level in olive trees at an early stage, a combined method of geostatistics and discriminant analysis was implemented. The results of cross-validation for the non-parametric classification method were of overall accuracy = 0.69, mean error rate = 0.31, and for the early detection class of accuracy 0.77 and misclassification probability 0.23. The results are promising and encourage the application of UAV technology for the early detection of Xfp infection.

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Skipping the Insect Vector: Plant Stolon Transmission of the Phytopathogen ‘Ca. Phlomobacter fragariae’ from the Arsenophonus Clade of Insect Endosymbionts

Insects ◽

10.3390/insects12020093 ◽

2021 ◽

Vol 12 (2) ◽

pp. 93

Author(s):

Jessica Dittmer ◽

Thierry Lusseau ◽

Xavier Foissac ◽

Franco Faoro

Keyword(s):

Plant Pathogens ◽

Model Systems ◽

Insect Vector ◽

Evolutionary Perspective ◽

Evolutionary Transition ◽

Strawberry Plant ◽

Disease Symptoms ◽

Transmission Electron ◽

Nutrient Provisioning ◽

Early Growth Phase

The genus Arsenophonus represents one of the most widespread clades of insect endosymbionts, including reproductive manipulators and bacteriocyte-associated primary endosymbionts. Two strains belonging to the Arsenophonus clade have been identified as insect-vectored plant pathogens of strawberry and sugar beet. The bacteria accumulate in the phloem of infected plants, ultimately causing leaf yellows and necrosis. These symbionts therefore represent excellent model systems to investigate the evolutionary transition from a purely insect-associated endosymbiont towards an insect-vectored phytopathogen. Using quantitative PCR and transmission electron microscopy, we demonstrate that ‘Candidatus Phlomobacter fragariae’, bacterial symbiont of the planthopper Cixius wagneri and the causative agent of Strawberry Marginal Chlorosis disease, can be transmitted from an infected strawberry plant to multiple daughter plants through stolons. Stolons are horizontally growing stems enabling the nutrient provisioning of daughter plants during their early growth phase. Our results show that Phlomobacter was abundant in the phloem sieve elements of stolons and was efficiently transmitted to daughter plants, which rapidly developed disease symptoms. From an evolutionary perspective, Phlomobacter is, therefore, not only able to survive within the plant after transmission by the insect vector, but can even be transmitted to new plant generations, independently from its ancestral insect host.

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Enzootic Activity of Chlamydia in Farms Located in a Hotspot Area for Zoonosis Emergence

10.21203/rs.3.rs-1014196/v1 ◽

2021 ◽

Author(s):

Ezequiel Andres Vanderhoeven ◽

Jessica P. Mosmann ◽

Adrián Díaz ◽

Cecilia G. Cuffini

Keyword(s):

Bird Species ◽

Farm Animals ◽

Economic Losses ◽

Wild Mammals ◽

Specific Pcr ◽

Chlamydial Species ◽

Zoonotic Risk ◽

Two Samples ◽

In The Wild ◽

First Time

Abstract Chlamydias are obligated intracellular Gram-negative bacteria, considered important zoonotic pathogens, broadly present in several bird species and responsible for economic losses in animal production. We analyzed the presence of Chlamydial species with zoonotic risk in farm animals in a highly biodiverse area and with great human circulation, the Argentine, Brazil and Paraguay tri-border area. We surveyed nine farms in an area and nasally swabbed a total of 62 animals. DNA was extracted and specific PCR was performed to identify chlamydial species. We detected Chlamydia spp . in 6.5% (4/62) of the animals tested, positive samples belonged to cattle and none of them showed symptoms of respiratory disease nor had been diagnose with reproductive diseases. Specific nested PCR confirmed two samples belonged to C. pecorum and two to C. psittaci . We report for the first time Chlamydia circulation with zoonotic risk in the region. Surveys in birds and wild mammals could give a better understanding to know what Chlamydial species are circulating in the wild interface. The zoonotic potential should be taking into account as farm workers and the surrounding population could be silent carriers or have respiratory diseases being underdiagnosed, and therefore should be considered in the differential diagnoses.

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Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v84i1.1412 ◽

2017 ◽

Vol 84 (1) ◽

Cited By ~ 2

Author(s):

Purity K. Gitonga ◽

Kariuki Ndung’u ◽

Grace A. Murilla ◽

Paul C. Thande ◽

Florence N. Wamwiri ◽

...

Keyword(s):

Survival Time ◽

Trypanosoma Brucei ◽

Acute Infection ◽

Glossina Pallidipes ◽

Trypanosoma Congolense ◽

Tsetse Fly ◽

Economic Losses ◽

Entire Group ◽

Tsetse Flies ◽

African Countries

African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.). In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6). We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP) periods were 8.4 ± 0.9 (range, 4–11) and 4.5 ± 0.2 (range, 4–6) for T. congolense and T. brucei isolates, respectively (p < 0.01). Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05) shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

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Draft Genome Sequence of “ Candidatus Phytoplasma oryzae” Strain Mbita1, the Causative Agent of Napier Grass Stunt Disease in Kenya

Genome Announcements ◽

10.1128/genomea.00297-16 ◽

2016 ◽

Vol 4 (2) ◽

Cited By ~ 9

Author(s):

Anne Fischer ◽

Ivette Santana-Cruz ◽

Lillian Wambua ◽

Cassandra Olds ◽

Charles Midega ◽

...

Keyword(s):

Genome Sequence ◽

Agricultural Production ◽

Plant Pathogens ◽

Genomic Organization ◽

Draft Genome ◽

Napier Grass ◽

Eastern Africa ◽

Draft Genome Sequence ◽

Economic Losses ◽

Insight Into

Phytoplasmas are bacterial plant pathogens with devastating impact on agricultural production worldwide. In eastern Africa, Napier grass stunt disease causes serious economic losses in the smallholder dairy industry. This draft genome sequence of “ Candidatus Phytoplasma oryzae” strain Mbita1 provides insight into its genomic organization and the molecular basis of pathogenicity.

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Methods for management of soilborne plant pathogens

Pesticidi i fitomedicina ◽

10.2298/pif1701009m ◽

2017 ◽

Vol 32 (1) ◽

pp. 9-24 ◽

Cited By ~ 12

Author(s):

Milica Mihajlovic ◽

Emil Rekanovic ◽

Jovana Hrustic ◽

Mila Grahovac ◽

Brankica Tanovic

Keyword(s):

Methyl Bromide ◽

Agricultural Production ◽

Plant Pathogens ◽

Current Knowledge ◽

Montreal Protocol ◽

Economic Losses ◽

Simultaneous Application ◽

Soilborne Disease ◽

Single Chemical ◽

Soil Disinfection

Soilborne pathogens cause significant economic losses in agricultural production all over the world. These species can survive for many years in the absence of a host plant by forming persistent structures such as microsclerotia, sclerotia, chlamydospores or oospores. Consequently, soilborne diseases are particularly difficult to predict, detect, diagnose and successfully control. Over the past 30 years, a fumigant, methyl bromide, has been widely used for their control in many crops. In 1992, methyl bromide was listed as an ozone-depleting substance under the Montreal Protocol ? an international treaty to protect the ozone layer. During the phaseout of methyl bromide, problems generated in agricultural production made it clear that dependence on a single method or a single chemical should be avoided. The objective of this review paper was to summarize the current knowledge about different methods of soilborne disease control including: crop rotation, steam soil disinfection, soil amendments, hydroponics and soilless growing systems, soil solarization, grafting, biological control and use of natural compounds, and chemical control. Positive and negative aspects of all available methods were reviewed. Benefits, achieved by simultaneous application of several methods based on different mechanisms of actions, are discussed.

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Injectisome T3SS Subunits As Potential Chaperones In The Extracellular Export of Pectobacterium Carotovorum Subsp. Carotovorum Bacteriocins Carocin S1 And Carocin S3 Secreted Via Flagellar T3SS

10.21203/rs.3.rs-590298/v1 ◽

2021 ◽

Author(s):

Hang-Cheng Chen ◽

Reymund C. Derilo ◽

Han-Ling Chen ◽

Tzu-Rung Li ◽

Ruchi Briam James S. Lagitnay ◽

...

Keyword(s):

Type Iii Secretion ◽

Insertional Mutagenesis ◽

Plant Pathogens ◽

Soft Rot ◽

Economic Losses ◽

Pectobacterium Carotovorum ◽

Secretion Systems ◽

Unique Type ◽

Bacterial Flagellum ◽

Type Iii

Abstract Pectobacterium carotovorum subsp. carotovorum (Pcc) causes soft-rot disease in a wide variety of plants resulting in economic losses worldwide. It produces various types of bacteriocin to compete against related plant pathogens. Studies on how bacteriocins are extracellularly secreted are conducted to understand the mechanism of interbacterial competition. In this study, the secretion of the low-molecular-weight bacteriocins (LMWB) Carocin S1 and Carocin S3 produced by a multiple-bacteriocin producing strain of Pcc, 89-H-4, was investigated. Tn5 insertional mutagenesis was used to generate a mutant, TH22-6, incapable of LMWBs secretion. Sequence and homology analyses of the gene disrupted by transposon Tn5 insertion revealed that the gene sctT, an essential component of the injectisome type III secretion machinery (T3aSS), is required for the secretion of the bacteriocins. This result raised a question regarding the nature of the secretion mechanism of Pcc bacteriocins which was previously discovered to be secreted via T3bSS, a system that utilizes the bacterial flagellum for extracellular secretions. Our previous report has shown that bacteriocin Carocin S1 cannot be secreted by mutants that are defective of T3bSS-related genes such as flhA, flhC, flhD and fliC. We knocked out several genes making up the significant structural components of both T3aSS and T3bSS. The findings led us to hypothesize the potential roles of the T3aSS-related proteins, SctT, SctU and SctV, as flagellar T3SS chaperones in the secretion of Pcc bacteriocins. This current discovery and the findings of our previous study helped us to conceptualize a unique Type III secretion system for bacteriocin extracellular export which is a hybrid of the injectisome and flagellar secretion systems.

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When time really is money: in situ quantification of the strobilurin resistance mutation G143A in the wheat pathogen Blumeria graminis f. sp. tritici

10.1101/2020.08.20.258921 ◽

2020 ◽

Author(s):

Kejal N Dodhia ◽

Belinda A Cox ◽

Richard P Oliver ◽

Francisco J Lopez-Ruiz

Keyword(s):

Fungicide Resistance ◽

Plant Pathogens ◽

Resistance Mutation ◽

Digital Pcr ◽

Blumeria Graminis ◽

Diagnostic Methods ◽

Sample Collection ◽

Specific Pcr ◽

Field Samples

AbstractBackgroundThere has been an inexorable increase in the incidence of fungicide resistance in plant pathogens in recent years. Control of diseases and the management of resistance would be greatly aided by rapid diagnostic methods. Quantitative allele specific PCR (ASqPCR) is an ideal technique for the analysis of fungicide resistance in the field as it can both detect and quantify the frequency of mutations associated with fungicide resistance. We have applied this technique to the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), an obligate biotrophic fungus that causes wheat powdery mildew and is responsible for up to 25% yield loss annually. In Australia, strobilurin resistant Bgt was first discovered in samples from Tasmania and Victoria in 2016. Molecular analysis revealed a nucleotide transversion in the cytochrome bc1 enzyme (cytb) complex, resulting in a substitution of alanine for glycine at position 143 (G143A) in Cytb.ResultsWe have developed an in-field ASqPCR assay that can quantify both the resistant (A143) and sensitive (G143) cytb alleles down to 1.67% in host and Bgt DNA mixtures within 90 min of sample collection. The in situ analysis of field samples collected during a survey in Tasmania revealed A143 frequencies ranging between 9-100%. We validated the analysis with a newly developed laboratory based digital PCR assay and found no significant differences between the two methods.ConclusionWe have successfully developed an in-field quantification method, for a QoI resistant allele, by pairing an ASqPCR assay on a lightweight qPCR instrument with a quick DNA extraction method. The deployment of this type of methodologies in the field can contribute to the effective in-season management of fungicide resistance.

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Genome Resources for the Ex-type of Phytophthora citricola, and well-authenticated isolates of P. hibernalis, P. nicotianae and P. syringae

Phytopathology ◽

10.1094/phyto-04-21-0167-a ◽

2021 ◽

Author(s):

Subodh K. Srivastava ◽

Leandra M. Knight ◽

Mark K. Nakhla ◽

Z. Gloria Abad

Keyword(s):

Plant Pathogens ◽

High Throughput Sequencing ◽

Economic Losses ◽

Biological Research ◽

Type Specimens ◽

High Coverage ◽

Oxford Nanopore ◽

Long Read ◽

Basic And Applied Research ◽

Diagnostic Applications

Phytophthora is one of the most important genera of plant pathogens with many members causing high economic losses world-wide. To build robust molecular identification systems, it is very important to have information from well-authenticated specimens and in preference the ex-type specimens. The reference genomes of well-authenticated specimens form a critical foundation for genetics, biological research, and diagnostic applications. In this study, we describe four draft Phytophthora genomes resources for the Ex-type of P. citricola BL34 (P0716 WPC) (118 contigs for 50 Mb), and well-authenticated specimens of P. syringae BL57G (P10330 WPC) (591 contigs for 75 Mb), P. hibernalis BL41G (P3822 WPC) (404 contigs for 84 Mb), and P. nicotianae BL162 (P6303 WPC) (3984 contigs for 108 Mb) generated with MinION long-read High-Throughput Sequencing (HTS) technology (Oxford Nanopore Technologies, ONT). Using the quality reads we assembled high coverage genomes of P. citricola with 291X coverage and 16,662 annotated genes; P. nicotianae with 205X coverage and 29,271 annotated genes; P. syringae with 76X coverage and 23,331 annotated genes, and P. hibernalis with 42X coverage and 21,762 annotated genes. With the availability of genomes sequences and its annotations, we predict that these draft genomes will be accommodating for various basic and applied research including diagnostics to protect global agriculture.

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Zagadnienie mocarstwowości Francji w dobie V Republiki (do 2007 roku)

Kwartalnik Kolegium Ekonomiczno-Społecznego Studia i Prace ◽

10.33119/kkessip.2012.1.9 ◽

2012 ◽

pp. 233-284

Author(s):

Marta Pachocka

Keyword(s):

World War Ii ◽

World War ◽

African Countries ◽

Fifth Republic ◽

Mediterranean Countries ◽

Fourth Republic ◽

French Foreign Policy ◽

Multilateral Diplomacy ◽

De Gaulle

During World War II and the postwar years, France’s international position has been weakened. The seizure of power by Charles de Gaulle in 1958 contributed to a stabilization of the political situation in the country and to a redefinition of French foreign policy. The article analyzes the international position of France from the end of World War II until 2007, when Nicolas Sarkozy won the presidential election. Thus, the article covers the period of the existence of two French republics: the Fourth Republic in the years 1946–1958 and the Fifth Republic, which remains Hexagone’s contemporary political system since 1958. The article consists of three parts. In the first part the external and internal conditions of the birth of the Fifth Republic are presented, with particular emphasis on the role of its creator – Ch. de Gaulle. The second part discusses the importance of France in Europe aft er 1945, emphasizing its contribution to the process of European integration and to the development of relations with the countries of Central and Eastern Europe, the USSR/Russian Federation and the Mediterranean countries. Then, the third part of my article stresses the position of France in the system of international relations after World War II, analyzing it on the example of Franco-American and Franco-NATO relations, the French policy towards the Arab and African countries, and finally, on the example of the Republic’s multilateral diplomacy. I conclude that in the examined period 1945–2007 France is an example of the former global superpower, which builds and strengthens its international position as a regional power with global interests.

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