scholarly journals Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

2016 ◽  
Vol 82 (14) ◽  
pp. 4330-4339 ◽  
Author(s):  
G. Laloi ◽  
J. Montarry ◽  
M. Guibert ◽  
D. Andrivon ◽  
D. Michot ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ascochyta Blight ◽  
Growing Season ◽  
Climatic Conditions ◽  
Single Population ◽  
High Genetic Diversity ◽  
Content Type ◽  
Didymella Pinodes ◽  
Pathogenicity Tests ◽  
Cropping Seasons

ABSTRACTAscochyta blight, caused by the necrotrophic ascomyceteDidymella pinodes, is responsible for severe losses in winter and spring pea crops. Despite different climatic conditions, epidemics on winter and spring crops are due to a single population ofD. pinodes, suggesting gene flow either between the two crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520D. pinodesstrains throughout a growing season from winter and spring pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring crops and that the most aggressive isolates are selected as an epidemic progresses.IMPORTANCEAscochyta blight, caused byDidymella pinodes, is responsible for severe losses in pea crops. While previous studies have shown that ascochyta blight epidemics on winter and spring crops are due to a single population ofD. pinodes, suggesting that isolates from the two crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic.

scholarly journals Genetic Diversity and Structure of Latvian Tilia cordata Populations

2021 ◽  
Vol 75 (4) ◽  
pp. 261-267
Author(s):  
Dainis Edgars Ruņģis ◽  
Baiba Krivmane
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
Vegetative Reproduction ◽  
Growth Conditions ◽  
Climatic Conditions ◽  
Tilia Cordata ◽  
High Genetic Diversity ◽  
Genetic Diversity And Structure ◽  
Broadleaf Tree ◽  
Broadleaf Species

Abstract Changing climatic conditions are transforming the ecological and silvicultural roles of broadleaf tree species in northern Europe. Small-leaved lime (Tilia cordata Mill.) is distributed throughout most of Europe, and is a common broadleaf species in Latvia. This species can tolerate a broad range of environmental and ecological conditions, including temperature, water availability, and soil types. The aim of this study was to assess the genetic diversity and differentiation of Latvian T. cordata populations using nuclear microsatellite markers developed for Tilia platyphyllos. After testing of 15 microsatellite markers, Latvian T. cordata samples were genotyped at 14 micro-satellite loci. Latvian T. cordata populations had high genetic diversity, and were not overly isolated from each other, with moderate gene flow between populations. No highly differentiated populations were identified. Vegetative reproduction was identified in most analysed populations, and almost one-third of analysed individuals are of clonal origin. T. cordata has high timber production potential under the current climatic and growth conditions in Latvia, and therefore this species has potential for use in forestry, as well as playing a significant role in maintaining biodiversity and other ecosystem services.

scholarly journals Molecular Typing Reveals High Genetic Diversity of Xanthomonas translucens Strains Infecting Small-Grain Cereals in Iran

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Moein Khojasteh ◽  
S. Mohsen Taghavi ◽  
Pejman Khodaygan ◽  
Habiballah Hamzehzarghani ◽  
Gongyou Chen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Global Scale ◽  
Population Diversity ◽  
Bacterial Leaf Streak ◽  
High Genetic Diversity ◽  
Center Of Origin ◽  
Content Type ◽  
Xanthomonas Translucens ◽  
Insight Into

ABSTRACT This study provides a phylogeographic insight into the population diversity of Xanthomonas translucens strains causing bacterial leaf streak disease of small-grain cereals in Iran. Among the 65 bacterial strains isolated from wheat, barley, and gramineous weeds in eight Iranian provinces, multilocus sequence analysis and typing (MLSA and MLST) of four housekeeping genes (dnaK, fyuA, gyrB, and rpoD), identified 57 strains as X. translucens pv. undulosa, while eight strains were identified as X. translucens pv. translucens. Although the pathogenicity patterns on oat and ryegrass weed species varied among the strains, all X. translucens pv. undulosa strains were pathogenic on barley, Harding’s grass, rye (except for XtKm35) and wheat, and all X. translucens pv. translucens strains were pathogenic on barley and Harding’s grass, while none of the latter group was pathogenic on rye or wheat (except for XtKm18). MLST using the 65 strains isolated in Iran, as well as the sequences of the four genes from 112 strains of worldwide origin retrieved from the GenBank database, revealed higher genetic diversity (i.e., haplotype frequency, haplotype diversity, and percentage of polymorphic sites) among the Iranian population of X. translucens than among the North American strains of the pathogen. High genetic diversity of the BLS pathogen in Iran was in congruence with the fact that the Iranian Plateau is considered the center of origin of cultivated wheat. However, further studies using larger collections of strains are warranted to precisely elucidate the global population diversity and center of origin of the pathogen. IMPORTANCE Bacterial leaf streak (BLS) of small-grain cereals (i.e., wheat and barley) is one of the economically important diseases of gramineous crops worldwide. The disease occurs in many countries across the globe, with particular importance in regions characterized by high levels of precipitation. Two genetically distinct xanthomonads—namely, Xanthomonas translucens pv. undulosa and X. translucens pv. translucens—have been reported to cause BLS disease on small-grain cereals. As seed-borne pathogens, the causal agents are included in the A2 list of quarantine pathogens by the European and Mediterranean Plant Protection Organization (EPPO). Despite its global distribution and high economic importance, the population structure, genetic diversity, and phylogeography of X. translucens remain undetermined. This study, using MLSA and MLST, provides a global-scale phylogeography of X. translucens strains infecting small-grain cereals. Based on the diversity parameters, neutrality indices, and population structure, we observe higher genetic diversity of the BLS pathogen in Iran, which is geographically close to the center of origin of common wheat, than has so far been observed in other areas of the world, including North America. The results obtained in this study provide a novel insight into the genetic diversity and population structure of the BLS pathogen of small-grain cereals on a global scale.

scholarly journals Complete Genome Sequence of Psittacine Adenovirus 1, Identified from Poicephalus senegalus in Italy

2018 ◽  
Vol 7 (11) ◽  
Author(s):  
Adelaide Milani ◽  
Gianpiero Zamperin ◽  
Alice Fusaro ◽  
Annalisa Salviato ◽  
Luca Bano ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Full Genome Sequence ◽  
Full Genome ◽  
High Genetic Diversity ◽  
Content Type ◽  
First Time

Using a metagenomics approach, we were able to determine for the first time the full-genome sequence of a psittacine adenovirus 1 isolate that was recovered from the liver of a dead Senegal parrot (Poicephalus senegalus) in Italy. The results of the phylogenetic investigations revealed the existence of high genetic diversity among adenoviruses circulating in psittacine birds.

scholarly journals Photobacterium damselaesubsp.damselae, a Generalist Pathogen with Unique Virulence Factors and High Genetic Diversity

2018 ◽  
Vol 200 (15) ◽  
Author(s):  
Carlos R. Osorio ◽  
Ana Vences ◽  
Xosé M. Matanza ◽  
Mateus S. Terceti
Keyword(s):  
Genetic Diversity ◽  
Virulence Factors ◽  
Cell Envelope ◽  
Fatal Outcome ◽  
Regulatory System ◽  
Cytolytic Activity ◽  
Conjugative Plasmid ◽  
Marine Animals ◽  
High Genetic Diversity ◽  
Content Type

ABSTRACTPhotobacterium damselaesubsp.damselaecauses vibriosis in a variety of marine animals, including fish species of importance in aquaculture. It also may cause wound infections in humans that can progress to a fatal outcome. Two major virulence factors are encoded within the large conjugative plasmid pPHDD1, the phospholipase D damselysin (Dly) and the pore-forming toxin phobalysin P (PhlyP). The two toxins exert hemolytic and cytolytic activities in a synergistic manner. Even though PhlyP has close homologues in manyVibriospecies, it has unique features that differentiate it from related toxins. Dly phospholipase constitutes a singular trait ofP. damselaesubsp.damselaeamong theVibrionaceae, although related toxins are found in members of theAeromonadaceae. Fish farm outbreaks can also be caused by plasmidless strains. Such observations led to the characterization of two ubiquitous chromosome-encoded toxins with lesser cytolytic activity, the pore forming-toxin phobalysin C (PhlyC) and the phospholipase-hemolysin PlpV. The high genetic diversity of this pathogen deserves special attention, as it has a number of strain-specific features, including the cell envelope polysaccharide synthesis clusters. Fish outbreaks are likely caused by multiclonal populations which contain both plasmidless and pPHDD1-harboring isolates and not by well-adapted clonal complexes. Still, among such genetic heterogeneity, it is feasible to identify conserved weak points in the biology of this bacterium: the two-component regulatory system RstAB (CarSR) was found to be necessary for the maximal production of virulence factors, and its inactivation severely impaired virulence.

scholarly journals High Genetic Diversity in Flavobacterium psychrophilum Isolates from Healthy Rainbow Trout (Oncorhynchus mykiss) Farmed in the Same Watershed, Revealed by Two Typing Methods

2020 ◽  
Vol 87 (2) ◽  
Author(s):  
Ségolène Calvez ◽  
Nora Navarro-Gonzalez ◽  
Charlène Siekoula-Nguedia ◽  
Catherine Fournel ◽  
Eric Duchaud
Keyword(s):  
Genetic Diversity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Clonal Complex ◽  
Economic Losses ◽  
High Genetic Diversity ◽  
Content Type ◽  
Flavobacterium Psychrophilum ◽  
Sequence Types ◽  
Apparently Healthy

ABSTRACT Flavobacterium psychrophilum affects salmonid health worldwide and causes economic losses. The genetic diversity of the pathogen must be considered to develop control methods. However, previous studies have reported both high and low levels of genetic diversity. The present longitudinal study aimed at assessing the genetic diversity of F. psychrophilum at a small temporal and geographic scale. Four farms located on the same watershed in France were studied. Rainbow trout (Oncorhynchus mykiss) batches were monitored, and apparently healthy individuals were sampled over 1 year. A total of 288 isolates were recovered from fish organs (gills and spleen) and eggs. Pulsed field gel electrophoresis revealed high genetic diversity. Multilocus sequence typing performed on a selection of 31 isolates provided congruent results, as follows: 18 sequence types (STs) were found, of which 13 were novel. The mean gene diversity (H = 0.8413) was much higher than that previously reported for this host species, although the sampling was restricted to a single watershed and 1 year. Seven isolates out of 31 were assigned to clonal complex ST10 (CC-ST10), which is the predominant clonal complex in the main salmonid production areas. A split decomposition tree reflected a panmictic population. This finding is important for aquaculture veterinarians in their diagnostic procedure, as the choice of adequate antibiotic treatment is conditioned by the correct identification of the causative agent. Furthermore, this study expands our knowledge on genetic diversity required for the development of an effective vaccine against F. psychrophilum. IMPORTANCE The bacterium Flavobacterium psychrophilum is a serious pathogen in many fish species, especially salmonids, that is responsible for considerable economic losses worldwide. In order to treat infections and to develop vaccines, the genetic diversity of this bacterium needs to be known. We assessed the genetic diversity of F. psychrophilum isolates from apparently healthy rainbow trout raised in several fish farms in the same watershed in France. Two different genotyping methods revealed high diversity. The majority of isolates were unrelated to clonal complex sequence type 10 (CC-ST10), the clonal complex that is predominant worldwide and associated with disease in rainbow trout. In addition, we found 13 novel sequence types. These results suggest that a diverse subpopulation of F. psychrophilum may be harbored by rainbow trout.

scholarly journals Interactions Between Environment and Genetic Diversity in Perennial Grass Phenology: A Review of Processes at Plant Scale and Modeling

2021 ◽  
Vol 12 ◽  
Author(s):  
Simon Rouet ◽  
Romain Barillot ◽  
Denis Leclercq ◽  
Marie-Hélène Bernicot ◽  
Didier Combes ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Environmental Conditions ◽  
Floral Induction ◽  
Perennial Grass ◽  
Reproductive Development ◽  
Climatic Conditions ◽  
Perennial Grasses ◽  
Intraspecific Diversity ◽  
High Genetic Diversity ◽  
Complex Interactions

In perennial grasses, the reproductive development consists of major phenological stages which highly determine the seasonal variations of grassland biomass production in terms of quantity and quality. The reproductive development is regulated by climatic conditions through complex interactions subjected to high genetic diversity. Understanding these interactions and their impact on plant development and growth is essential to optimize grassland management and identify the potential consequences of climate change. Here, we review the main stages of reproductive development, from floral induction to heading, i.e., spike emergence, considering the effect of the environmental conditions and the genetic diversity observed in perennial grasses. We first describe the determinants and consequences of reproductive development at individual tiller scale before examining the interactions between plant tillers and their impact on grassland perenniality. Then, we review the available grassland models through their ability to account for the complexity of reproductive development and genetic × environmental interactions. This review shows that (1) The reproductive development of perennial grasses is characterized by a large intraspecific diversity which has the same order of magnitude as the diversity observed between species or environmental conditions. (2) The reproductive development is determined by complex interactions between the processes of floral induction and morphogenesis of the tiller. (3) The perenniality of a plant is dependent on the reproductive behavior of each tiller. (4) Published models only partly explain the complex interactions between morphogenesis and climate on reproductive development. (5) Introducing more explicitly the underlying processes involved in reproductive development in models would improve our ability to anticipate grassland behavior in future growth conditions.

scholarly journals Comparative Population Analysis of Klebsiella pneumoniae Strains with Extended-Spectrum β-Lactamases Colonizing Patients in Rehabilitation Centers in Four Countries

2013 ◽  
Vol 57 (4) ◽  
pp. 1992-1997 ◽  
Author(s):  
A. Baraniak ◽  
R. Izdebski ◽  
J. Fiett ◽  
E. Sadowy ◽  
A. Adler ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Klebsiella Pneumoniae ◽  
Population Analysis ◽  
International Project ◽  
High Genetic Diversity ◽  
Content Type ◽  
Rehabilitation Centers ◽  
Extended Spectrum ◽  
Comparative Population

ABSTRACTThe international project MOSAR was conducted in five rehabilitation centers; patients were screened for rectal carriage of extended-spectrum β-lactamase (ESBL)-producing members of theEnterobacteriaceae. Among 229Klebsiella pneumoniaeisolates, four clonal groups (CG) or complexes (CC) prevailed: CG17 in France, CG101 in Italy, CG15 in Spain, and CC147 in Israel. ESBLs, mainly CTX-Ms, were produced by 226 isolates; three isolates expressed AmpC-like cephalosporinases. High genetic diversity ofK. pneumoniaepopulations was observed, with specific characteristics at each center.

scholarly journals High frequency of colonization by diverse clones of beta-lactam-resistant Gram-negative bacilli in haemodialysis: different sources of transmission outside the renal unit?

2020 ◽  
Vol 69 (9) ◽  
pp. 1132-1144
Author(s):  
Johanna M. Vanegas ◽  
Lorena Salazar-Ospina ◽  
Daniela Montoya-Urrego ◽  
Julián Builes ◽  
Gustavo E. Roncancio ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Type Species ◽  
Molecular Characteristics ◽  
Renal Unit ◽  
Beta Lactam ◽  
High Genetic Diversity ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Stool Samples

Introduction. While colonization by Staphylococcus aureus in haemodialysis patients has been assessed, knowledge about colonization by beta-lactam-resistant Gram-negative bacilli is still limited. Aim. To describe clinical and molecular characteristics in haemodialysis patients colonized by S. aureus (MSSA-MRSA) and beta-lactam-resistant Gram-negative bacilli in an ambulatory renal unit. Methodology. The study included patients with central venous catheters in an outpatient haemodialysis facility in Medellín, Colombia (October 2017–October 2018). Swab specimens were collected from the nostrils and skin around vascular access to assess colonization by S. aureus (MSSA-MRSA). Stool samples were collected from each patient to evaluate beta-lactam-resistant Gram-negative bacilli colonization. Molecular typing included PFGE, multilocus sequence typing (MLST), spa typing and enterobacterial repetitive intergenic consensus-PCR (ERIC). Clinical information was obtained from medical records and personal interview. Results. A total of 210 patients were included in the study. S. aureus colonization was observed in 33.8 % (n=71) of the patients, 4.8 % (n=10) of which were colonized by methicillin-resistant S. aureus . Stool samples were collected from 165 patients and of these 41.2 % (n=68) and 11.5 % (n=19) were colonized by extended-spectrum-beta-lactamase-producing (ESBL) and carbapenem-resistant bacilli, respectively. Typing methods revealed high genetic diversity among S. aureus and ESBL-producing Gram-negative bacilli (ESBL-GNB). Antibiotic use and hospitalization in the previous 6 months were observed in more than half of the studied population. Conclusion. The high colonization by ESBL-GNB in haemodialysis patients shows evidence for the need for stronger surveillance, not only for S. aureus but also for multidrug-resistant bacilli in order to avoid their spread. Additionally, the high genetic diversity suggests other sources of transmission outside the renal unit instead of horizontal transmission between patients.

scholarly journals Association of Bartonella Species with Wild and Synanthropic Rodents in Different Brazilian Biomes

2016 ◽  
Vol 82 (24) ◽  
pp. 7154-7164 ◽  
Author(s):  
Luiz Ricardo Gonçalves ◽  
Alexsandra Rodrigues de Mendonça Favacho ◽  
André Luiz Rodrigues Roque ◽  
Natalia Serra Mendes ◽  
Otávio Luiz Fidelis Junior ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Bayesian Inference ◽  
Maximum Likelihood ◽  
Target Genes ◽  
Phylogenetic Analyses ◽  
Wild Rodents ◽  
High Genetic Diversity ◽  
Content Type ◽  
Wide Range ◽  
The Impact

ABSTRACTBartonellaspp. comprise an ecologically successful group of microorganisms that infect erythrocytes and have adapted to different hosts, which include a wide range of mammals, besides humans. Rodents are reservoirs of about two-thirds ofBartonellaspp. described to date; and some of them have been implicated as causative agents of human diseases. In our study, we performed molecular and phylogenetic analyses ofBartonellaspp. infecting wild rodents from five different Brazilian biomes. In order to characterize the genetic diversity ofBartonellaspp., we performed a robust analysis based on three target genes, followed by sequencing, Bayesian inference, and maximum likelihood analysis.Bartonellaspp. were detected in 25.6% (117/457) of rodent spleen samples analyzed, and this occurrence varied among different biomes. The diversity analysis ofgltAsequences showed the presence of 15 different haplotypes. Analysis of the phylogenetic relationship ofgltAsequences performed by Bayesian inference and maximum likelihood showed that theBartonellaspecies detected in rodents from Brazil was closely related to the phylogenetic group A detected in other cricetid rodents from North America, probably constituting only one species. Last, theBartonellaspecies genogroup identified in the present study formed a monophyletic group that includedBartonellasamples from seven different rodent species distributed in three distinct biomes. In conclusion, our study showed that the occurrence ofBartonellabacteria in rodents is much more frequent and widespread than previously recognized.IMPORTANCEIn the present study, we reported the occurrence ofBartonellaspp. in some sites in Brazil. The identification and understanding of the distribution of this important group of bacteria may allow the Brazilian authorities to recognize potential regions with the risk of transmission of these pathogens among wild and domestic animals and humans. In addition, our study accessed important gaps in the biology of this group of bacteria in Brazil, such as its low host specificity, high genetic diversity, and relationship with otherBartonellaspp. detected in rodents trapped in America. Considering the diversity of newly discoveredBartonellaspecies and the great ecological plasticity of these bacteria, new studies with the aim of revealing the biological aspects unknown until now are needed and must be performed around the world. In this context, the impact ofBartonellaspp. associated with rodents in human health should be assessed in future studies.

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