An Experimental Test of the Host-Plant Range of Nonrecombinant Strains of North American Xylella fastidiosa subsp. multiplex

2019 ◽  
Vol 109 (2) ◽  
pp. 294-300 ◽  
Author(s):  
Leonard Nunney ◽  
Hamid Azad ◽  
Richard Stouthamer
Keyword(s):  
Homologous Recombination ◽  
Host Range ◽  
Xylella Fastidiosa ◽  
Sequence Type ◽  
Host Specialization ◽  
Washington Dc ◽  
Plant Host ◽  
Wide Range ◽  
Novel Host ◽  
Different Strains

Nonrecombinant strains of Xylella fastidiosa subsp. multiplex (those lacking evidence of significant intersubspecific homologous recombination) infect the xylem of a wide range of native and nonnative trees in North America. However, the degree to which different strains have a specialized host range remains poorly understood. We tested eight strains isolated from five different tree species (almond, olive, sweetgum, and plum in California and oak in Washington, DC). Experiments were conducted in greenhouses in Riverside, CA, and each strain was tested on 11 to 15 of the 17 plant species tested. Hosts infected by the most strains were plum (5 of 8 strains) and almond (4 of 8), while their congener peach was only infected by 1 of 8. No strains infected oleander or mulberry. All strains successfully infected their original host, with peach, olive (1 of 7), and sweetgum (2 of 6) only infected by such strains. Of the 90 total strain–novel-host combinations tested, 11 resulted in unambiguous infection, 2 gave ambiguous results, and the remaining 77 failed to result in symptoms or bacterial spread. All eight strains had a unique host range, including two pairs of strains with the same multilocus sequence typing sequence type, providing strong evidence of extensive plant-host specialization. There was little evidence that host relatedness was driving host specificity.

A New Sharpshooter Threatens Both Crops and Ornamentals

2000 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
Matthew J. Blua ◽  
Phil A. Phillips ◽  
Richard A. Redak
Keyword(s):  
Host Range ◽  
Potential Distribution ◽  
Xylella Fastidiosa ◽  
New Disease ◽  
Leaf Scorch ◽  
Economic Problems ◽  
The Future ◽  
Different Strains ◽  
Large Host ◽  
Almond Leaf Scorch

The glassy-winged sharpshooter (Homalodisca coagulate), an insect that has recently invaded California, and the smoke tree sharpshooter (Homalodisca lacerta) are creating serious new economic problems in both agricultural and ornamental plantings. The greatest threats surround their ability to spread the plantpathogenic bacterium Xylella fastidiosa, which induces Pierce's disease in grapevines, almond leaf scorch disease, and a new disease known as oleander leaf scorch. Because of the potential distribution and large host range of the glassywinged sharpshooter, other diseases caused by different strains of X. fastidiosa may have an even greater impact on the state's agricultural and ornamental landscape industries in the future. Posted 27 June 2000.

scholarly journals The host range of Aphis gossypii is dependent on aphid genetic background and feeding experience

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7774 ◽  
Author(s):  
Lin Ma ◽  
Meng-Yue Li ◽  
Chun-Yan Chang ◽  
Fang-Fang Chen ◽  
Yang Hu ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Host Range ◽  
Host Plants ◽  
Artificial Diet ◽  
Aphis Gossypii ◽  
Host Specialization ◽  
Broad Host Range ◽  
Feeding Experience ◽  
Wide Range ◽  
Cotton Plants

Background A polyphagous insect herbivore has a wide range of host plants. However, it has been found that many polyphagous herbivores commonly exhibit a strong preference for a subset of species in their broad host range, and various host biotypes exist in herbivore populations. Nutrition and secondary metabolites in plants affect herbivore preference and performance, but it is still not clear which factors determine the host range and host preference of polyphagous herbivores. Method Cotton-melon aphids, Aphis gossypii Glover, collected from cotton and cucumber crops, were used in this study. The genetic backgrounds of these aphids were detected using microsatellite PCR and six genotypes were evaluated. Performance of these six aphid genotypes on excised leaves and plants of cotton and cucumber seedlings were examined through a reciprocal transplant experiment. In order to detect whether the feeding experience on artificial diet would alter aphid host range, the six genotypes of aphids fed on artificial diet for seven days were transferred onto cotton and cucumber leaves, and then their population growth on these two host plants was surveyed. Results Aphids from cotton and cucumber plants could not colonize the excised leaves and intact plants of cucumber and cotton seedlings, respectively. All six genotypes of aphids collected from cotton and cucumber plants could survive and produce offspring on artificial diet, which lacked plant secondary metabolites. The feeding experience on the artificial diet did not alter the ability of all six genotypes to use their native host plants. However, after feeding on this artificial diet for seven days, two aphid genotypes from cotton and one from cucumber acquired the ability to use both of the excised leaves from cucumber and cotton plants. The two aphid genotypes from cotton conditioned by the feeding experience on artificial diet and then reared on excised cucumber leaves for >12 generations still maintained the ability to use intact cotton plants but did not establish a population on cucumber plants. However, one cucumber genotype conditioned by artificial diet and then reared on excised cotton leaves could use both the intact cotton and cucumber plants, showing that the expansion of host range was mediated by feeding experience. Conclusion Feeding experience on artificial diet induced the expansion of host range of the cucurbit-specialized A. gossypii, and this expansion was genotype-specific. We speculated that feeding on a constant set of host plants in the life cycle of aphids may contribute to the formation of host specialization.

scholarly journals Recent Evolutionary Radiation and Host Plant Specialization in the Xylella fastidiosa Subspecies Native to the United States

2013 ◽  
Vol 79 (7) ◽  
pp. 2189-2200 ◽  
Author(s):  
Leonard Nunney ◽  
Danel B. Vickerman ◽  
Robin E. Bromley ◽  
Stephanie A. Russell ◽  
John R. Hartman ◽  
...  
Keyword(s):  
United States ◽  
Xylella Fastidiosa ◽  
Bacterial Pathogen ◽  
The United States ◽  
Host Specialization ◽  
Broad Host Range ◽  
Plant Host ◽  
Content Type ◽  
Host Plant Specialization ◽  
Even Order

ABSTRACTThe bacterial pathogen,Xylella fastidiosa, infects many plant species in the Americas, making it a good model for investigating the genetics of host adaptation. We used multilocus sequence typing (MLST) to identify isolates of the native U.S. subsp.multiplexthat were largely unaffected by intersubspecific homologous recombination (IHR) and to investigate how their evolutionary history influences plant host specialization. We identified 110 “non-IHR” isolates, 2 minimally recombinant “intermediate” ones (including the subspecific type), and 31 with extensive IHR. The non-IHR and intermediate isolates defined 23 sequence types (STs) which we used to identify 22 plant hosts (73% trees) characteristic of the subspecies. Except for almond, subsp.multiplexshowed no host overlap with the introduced subspecies (subspeciesfastidiosaandsandyi). MLST sequences revealed that subsp.multiplexunderwent recent radiation (<25% of subspecies age) which included only limited intrasubspecific recombination (ρ/θ = 0.02); only one isolated lineage (ST50 from ash) was older. A total of 20 of the STs grouped into three loose phylogenetic clusters distinguished by nonoverlapping hosts (excepting purple leaf plum): “almond,” “peach,” and “oak” types. These host differences were not geographical, since all three types also occurred in California. ST designation was a good indicator of host specialization. ST09, widespread in the southeastern United States, only infected oak species, and all peach isolates were ST10 (from California, Florida, and Georgia). Only ST23 had a broad host range. Hosts of related genotypes were sometimes related, but often host groupings crossed plant family or even order, suggesting that phylogenetically plastic features of hosts affect bacterial pathogenicity.

scholarly journals The Epidemiology of Xylella fastidiosa; A Perspective on Current Knowledge and Framework to Investigate Plant Host–Vector–Pathogen Interactions

2019 ◽  
Vol 109 (2) ◽  
pp. 200-209 ◽  
Author(s):  
Michael Jeger ◽  
Claude Bragard
Keyword(s):  
Plant Pathogen ◽  
Current Knowledge ◽  
Xylella Fastidiosa ◽  
Plant Diseases ◽  
Model Framework ◽  
Plant Host ◽  
Wide Range ◽  
Epidemic Development ◽  
Host Infection ◽  
And Behavior

Insect-transmitted plant diseases caused by viruses, phytoplasmas, and bacteria share many features in common regardless of the causal agent. This perspective aims to show how a model framework, developed originally for plant virus diseases, can be modified for the case of diseases incited by Xylella fastidiosa. In particular, the model framework enables the specification of a simple but quite general invasion criterion defined in terms of key plant, pathogen, and vector parameters and, importantly, their interactions, which determine whether or not an incursion or isolated outbreak of a pathogen will lead to establishment, persistence, and subsequent epidemic development. Hence, this approach is applicable to the wide range of X. fastidiosa-incited diseases that have recently emerged in southern Europe, each with differing host plant, pathogen subspecies, and vector identities. Of particular importance are parameters relating to vector abundance and activity, transmission characteristics, and behavior in relation to preferences for host infection status. Some gaps in knowledge with regard to the developing situation in Europe are noted.

Isolation and properties of a bacteriophage lytic for a wide range of pseudomonads

1971 ◽  
Vol 17 (5) ◽  
pp. 677-682 ◽  
Author(s):  
R. A. Kelln ◽  
R. A. J. Warren
Keyword(s):  
Latent Period ◽  
Pseudomonas Fluorescens ◽  
Host Range ◽  
Burst Size ◽  
Broad Host Range ◽  
Lytic Bacteriophage ◽  
Bacterial Strains ◽  
Short Tail ◽  
Wide Range ◽  
Different Strains

The lytic bacteriophage ø-S1 was isolated from sewage using a strain of Pseudomonas fluorescens as host. It had a hexagonal head 60 nm in diameter and a short tail 30 nm long. ø-S1 had a broad host range, lysing strains from 10 biotypes of Pseudomonads. Although the latent period was fairly constant for the bacterial strains tested, the burst size varied considerably. The rate of adsorption of the phage to different strains also varied considerably.

scholarly journals The Coevolution of Plants and Microbes Underpins Sustainable Agriculture

2021 ◽  
Vol 9 (5) ◽  
pp. 1036
Author(s):  
Dongmei Lyu ◽  
Levini A. Msimbira ◽  
Mahtab Nazari ◽  
Mohammed Antar ◽  
Antoine Pagé ◽  
...  
Keyword(s):  
Microbial Community ◽  
Plant Growth ◽  
Stress Resistance ◽  
Mycorrhizal Fungi ◽  
Plant Tissues ◽  
Terrestrial Plants ◽  
Plant Host ◽  
Symbiotic Relationships ◽  
Wide Range ◽  
Terrestrial Environments

Terrestrial plants evolution occurred in the presence of microbes, the phytomicrobiome. The rhizosphere microbial community is the most abundant and diverse subset of the phytomicrobiome and can include both beneficial and parasitic/pathogenic microbes. Prokaryotes of the phytomicrobiome have evolved relationships with plants that range from non-dependent interactions to dependent endosymbionts. The most extreme endosymbiotic examples are the chloroplasts and mitochondria, which have become organelles and integral parts of the plant, leading to some similarity in DNA sequence between plant tissues and cyanobacteria, the prokaryotic symbiont of ancestral plants. Microbes were associated with the precursors of land plants, green algae, and helped algae transition from aquatic to terrestrial environments. In the terrestrial setting the phytomicrobiome contributes to plant growth and development by (1) establishing symbiotic relationships between plant growth-promoting microbes, including rhizobacteria and mycorrhizal fungi, (2) conferring biotic stress resistance by producing antibiotic compounds, and (3) secreting microbe-to-plant signal compounds, such as phytohormones or their analogues, that regulate aspects of plant physiology, including stress resistance. As plants have evolved, they recruited microbes to assist in the adaptation to available growing environments. Microbes serve themselves by promoting plant growth, which in turn provides microbes with nutrition (root exudates, a source of reduced carbon) and a desirable habitat (the rhizosphere or within plant tissues). The outcome of this coevolution is the diverse and metabolically rich microbial community that now exists in the rhizosphere of terrestrial plants. The holobiont, the unit made up of the phytomicrobiome and the plant host, results from this wide range of coevolved relationships. We are just beginning to appreciate the many ways in which this complex and subtle coevolution acts in agricultural systems.

scholarly journals Revealing biophysical properties of KfrA-type proteins as a novel class of cytoskeletal, coiled-coil plasmid-encoded proteins

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
M. Adamczyk ◽  
E. Lewicka ◽  
R. Szatkowska ◽  
H. Nieznanska ◽  
J. Ludwiczak ◽  
...  
Keyword(s):  
Dna Binding ◽  
Host Range ◽  
Coiled Coil ◽  
Amino Acid Sequences ◽  
Broad Host Range ◽  
Biophysical Properties ◽  
Dna Binding Sites ◽  
In Silico Studies ◽  
Wide Range

Abstract Background DNA binding KfrA-type proteins of broad-host-range bacterial plasmids belonging to IncP-1 and IncU incompatibility groups are characterized by globular N-terminal head domains and long alpha-helical coiled-coil tails. They have been shown to act as transcriptional auto-regulators. Results This study was focused on two members of the growing family of KfrA-type proteins encoded by the broad-host-range plasmids, R751 of IncP-1β and RA3 of IncU groups. Comparative in vitro and in silico studies on KfrAR751 and KfrARA3 confirmed their similar biophysical properties despite low conservation of the amino acid sequences. They form a wide range of oligomeric forms in vitro and, in the presence of their cognate DNA binding sites, they polymerize into the higher order filaments visualized as “threads” by negative staining electron microscopy. The studies revealed also temperature-dependent changes in the coiled-coil segment of KfrA proteins that is involved in the stabilization of dimers required for DNA interactions. Conclusion KfrAR751 and KfrARA3 are structural homologues. We postulate that KfrA type proteins have moonlighting activity. They not only act as transcriptional auto-regulators but form cytoskeletal structures, which might facilitate plasmid DNA delivery and positioning in the cells before cell division, involving thermal energy.

Host-vector systems

1989 ◽  
Vol 324 (1224) ◽  
pp. 477-485 ◽  
Keyword(s):  
Genetic Manipulation ◽  
Pharmaceutical Products ◽  
Host Cells ◽  
Animal Cells ◽  
Vector Systems ◽  
Wide Range ◽  
Novel Host ◽  
Basic Concepts ◽  
Foreign Genes ◽  
New Generation

In 1980 it was only possible to express foreign genes in bacteria and a few easily cultured animal cells. During the subsequent eight years specialized vectors have been developed to allow the genetic manipulation of a wide range of both prokaryotes and eukaryotes. One of the major goals of biotechnology in 1980 was to use host cells as ‘factories’ for the production of proteins that were only available in minute quantities from natural sources. This has already lead to a new generation of pharmaceutical products. Advances in our understanding of host-vector systems have defined new goals. The basic concepts of expression vector design will be illustrated. Some of the new goals are discussed with particular reference to the exploitation of novel host-vector systems to develop vaccines and anti-viral agents against AIDS.

scholarly journals How to Train Your Phage: The Recent Efforts in Phage Training

Biologics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 70-88
Author(s):  
Abdallah Abdelsattar ◽  
Alyaa Dawooud ◽  
Nouran Rezk ◽  
Salsabil Makky ◽  
Anan Safwat ◽  
...  
Keyword(s):  
Host Range ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Phage Therapy ◽  
Current Knowledge ◽  
Lytic Replication ◽  
Resistant Bacteria ◽  
Infection Cycles ◽  
Different Strains ◽  
Specific Species

Control of pathogenic bacteria by deliberate application of predatory phages has potential as a powerful therapy against antibiotic-resistant bacteria. The key advantages of phage biocontrol over antibacterial chemotherapy are: (1) an ability to self-propagate inside host bacteria, (2) targeted predation of specific species or strains of bacteria, (3) adaptive molecular machinery to overcome resistance in target bacteria. However, realizing the potential of phage biocontrol is dependent on harnessing or adapting these responses, as many phage species switch between lytic infection cycles (resulting in lysis) and lysogenic infection cycles (resulting in genomic integration) that increase the likelihood of survival of the phage in response to external stress or host depletion. Similarly, host range will need to be optimized to make phage therapy medically viable whilst avoiding the potential for deleteriously disturbing the commensal microbiota. Phage training is a new approach to produce efficient phages by capitalizing on the evolved response of wild-type phages to bacterial resistance. Here we will review recent studies reporting successful trials of training different strains of phages to switch into lytic replication mode, overcome bacterial resistance, and increase their host range. This review will also highlight the current knowledge of phage training and future implications in phage applications and phage therapy and summarize the recent pipeline of the magistral preparation to produce a customized phage for clinical trials and medical applications.

Host range and physiologic specialization in Rhynchosporium secalis

1974 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
SM Ali ◽  
WJR Boyd
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Environmental Conditions ◽  
Host Specialization ◽  
Rhynchosporium Secalis ◽  
Host Reaction ◽  
Genetic Studies ◽  
Barley Cultivars ◽  
Adequate Sampling ◽  
Pathogenic Variability

The pathogenic variability of isolates of R. secalis collected in Western Australia has been examined on different host genera of the Gramineae and on selected barley cultivars. Depending on the host-isolate combination and the conditions of the test, evidence has been obtained of inter- and intra-isolate variability in both host reaction and isolate pathogenicity. This complicates definitive interpretation of the results, militates against identification of conventional 'races' of the pathogen and shows that R. secalis does not exhibit strict host specialization. Hosts which consistently express resistance or susceptibility under different environmental conditions, and isolates which express their pathogenic characteristics consistently, have been identified. The need for more precise genetic studies and adequate sampling of genetic diversity is emphasized.

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