scholarly journals Molecular Epidemiology of Xanthomonas perforans Outbreaks in Tomato Plants from Transplant to Field as Determined by Single-Nucleotide Polymorphism Analysis

2019 ◽  
Vol 85 (18) ◽  
Author(s):  
Peter Abrahamian ◽  
Sujan Timilsina ◽  
Gerald V. Minsavage ◽  
Neha Potnis ◽  
Jeffrey B. Jones ◽  
...  

ABSTRACT Outbreaks of bacterial spot on tomato (BST) caused by Xanthomonas perforans are a major concern for sustainable crop production. BST is a common occurrence in tomato transplants grown for field production. We hypothesized that BST outbreaks in commercial fields originate from X. perforans strains inadvertently introduced from commercial transplant facilities. To test this hypothesis, we used a genome-wide single-nucleotide polymorphism (SNP) analysis to characterize X. perforans strains recovered from tomato transplant facilities and fields in commercial production areas. X. perforans strains were isolated from symptomatic transplants prior to roguing at two commercial transplant growers. Then, the same groups of transplants were tracked to commercial fields to recover X. perforans strains from diseased plants prior to harvest. Whole-genome sequencing was carried out on 84 strains isolated from transplant and field plants from Florida and South Carolina. SNPs were called using three reference strains that represented the genetic variation of the sampled strains. Field strains showing genetic similarity to transplant strains had a difference of 2 to 210 SNPs. Transplant and field strains clustered together by grower within each phylogenomic group, consistent with expectations. The range of genetic divergence among strains isolated from field plants was similar to the range obtained from strains on transplants. Using the range of genetic variation observed in transplants, we estimate that 60% to 100% of field strains were an extension of the transplant strain population. Our results stress the importance of BST management to reduce X. perforans movement from transplant to field and to minimize subsequent disease outbreaks. IMPORTANCE Current management of Xanthomonas perforans on tomato plants mainly relies on the frequent application of pesticides. However, the lack of effective pesticides and the development of strain tolerance to certain bactericides limit the ability to control outbreaks in production fields. Better knowledge of probable sources of X. perforans inoculum during tomato production is required to refine management strategies. Tomato plants are typically established in the field using transplants. This study aimed to determine if strains from field epidemics were coming from transplant facilities or resulted from local field outbreaks. The overall goal was to identify potential sources of inoculum and subsequently develop strategies to reduce carryover from transplant production to the field. Our results indicate that tomato producers should shift disease management efforts to transplant facilities to reduce disease in the field. Improved transplant health should reduce the likelihood of bacterial spot outbreaks and subsequently reduce pesticide usage in the field.

2014 ◽  
Vol 80 (7) ◽  
pp. 2125-2132 ◽  
Author(s):  
Narjol Gonzalez-Escalona ◽  
Ruth Timme ◽  
Brian H. Raphael ◽  
Donald Zink ◽  
Shashi K. Sharma

ABSTRACTClostridium botulinumis a genetically diverse Gram-positive bacterium producing extremely potent neurotoxins (botulinum neurotoxins A through G [BoNT/A-G]). The complete genome sequences of three strains harboring only the BoNT/A1 nucleotide sequence are publicly available. Although these strains contain a toxin cluster (HA+OrfX−) associated with hemagglutinin genes, little is known about the genomes of subtype A1 strains (termed HA−OrfX+) that lack hemagglutinin genes in the toxin gene cluster. We sequenced the genomes of three BoNT/A1-producingC. botulinumstrains: two strains with the HA+OrfX−cluster (69A and 32A) and one strain with the HA−OrfX+cluster (CDC297). Whole-genome phylogenic single-nucleotide-polymorphism (SNP) analysis of these strains along with other publicly availableC. botulinumgroup I strains revealed five distinct lineages. Strains 69A and 32A clustered with theC. botulinumtype A1 Hall group, and strain CDC297 clustered with theC. botulinumtype Ba4 strain 657. This study reports the use of whole-genome SNP sequence analysis for discrimination ofC. botulinumgroup I strains and demonstrates the utility of this analysis in quickly differentiatingC. botulinumstrains harboring identical toxin gene subtypes. This analysis further supports previous work showing that strains CDC297 and 657 likely evolved from a common ancestor and independently acquired separate BoNT/A1 toxin gene clusters at distinct genomic locations.


2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Anna Janowicz ◽  
Fabrizio De Massis ◽  
Massimo Ancora ◽  
Cesare Cammà ◽  
Claudio Patavino ◽  
...  

ABSTRACT The use of whole-genome sequencing (WGS) using next-generation sequencing (NGS) technology has become a widely accepted method for microbiology laboratories in the application of molecular typing for outbreak tracing and genomic epidemiology. Several studies demonstrated the usefulness of WGS data analysis through single-nucleotide polymorphism (SNP) calling from a reference sequence analysis for Brucella melitensis, whereas gene-by-gene comparison through core-genome multilocus sequence typing (cgMLST) has not been explored so far. The current study developed an allele-based cgMLST method and compared its performance to that of the genome-wide SNP approach and the traditional multilocus variable-number tandem repeat analysis (MLVA) on a defined sample collection. The data set was comprised of 37 epidemiologically linked animal cases of brucellosis as well as 71 isolates with unknown epidemiological status, composed of human and animal samples collected in Italy. The cgMLST scheme generated in this study contained 2,704 targets of the B. melitensis 16M reference genome. We established the potential criteria necessary for inclusion of an isolate into a brucellosis outbreak cluster to be ≤6 loci in the cgMLST and ≤7 in WGS SNP analysis. Higher phylogenetic distance resolution was achieved with cgMLST and SNP analysis than with MLVA, particularly for strains belonging to the same lineage, thereby allowing diverse and unrelated genotypes to be identified with greater confidence. The application of a cgMLST scheme to the characterization of B. melitensis strains provided insights into the epidemiology of this pathogen, and it is a candidate to be a benchmark tool for outbreak investigations in human and animal brucellosis.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4253-4253
Author(s):  
Yongjun Cha ◽  
Kwang-Sung Ahn ◽  
Juwon Park ◽  
Byung-Su Kim ◽  
Soo-Mee Bang ◽  
...  

Abstract As a result of numerous genetic aberrations, acute myeloid leukemia (AML) present with very heterogeneous clinical features. Moreover, structural and numerical chromosome aberrations currently comprise the most important basis for predicting these heterogeneous outcomes. However, 30 to 50 percent of AML patients have cytogenetically normal karyotypes. Though submicroscopic genetic alterations (such as NPM1, CEBPA, MLL-PTD) are increasingly being used for clinical purposes, additional markers with prognostic or predictive value are still lacking in this group. In this study, we performed a genome-wide, single-nucleotide polymorphism (SNP) study in order to identify novel genomic regions of interest in normal karyotype AML. 54 untreated AML patients with normal karyotypes were analyzed with an Illumina infinium 317K SNP chip assay. SNP genotype call rate was 99.8 percent, resulting in a resolution of 1 SNP/Mb. In a genome-wide SNP analysis, 317 SNP loci, having a significant difference between AML and normal control, were found. In addition, about 300 loci were also identified, showing a significant difference between patients who achieved CR and those who did not. Some of these were found to be related with drug metabolism and MDR family. Also we used the SNP assay to screen a loss of heterozygosity (LOH), suggesting possible involvement of tumor suppressor genes. In summary, 38 LOH regions larger than 1Mb were observed in 23 cases (43%) among 54 AML patients having normal karyotypes. Most (55%) of them were copy-neutral events and the most frequently identified alterations were located at 3p, 8p, 13q and 22q. 11 (29%) out of 38 LOH regions had overlapping parts among them. Some LOHs were correlated with response to chemotherapy. Various genetic changes were discovered by use of an SNP-based chip array in normal karyotype AML patients. Moreover, some of these were related with CR acquisition and drug metabolism. These results can be used to differentiate normal karyotype AML and warrant further study.


2018 ◽  
Vol 6 (25) ◽  
Author(s):  
Alisha A. Mullen ◽  
Ciara D. Lynch ◽  
Shannon M. Hill ◽  
Cian P. Holohan ◽  
Tadhg Ó Cróinín ◽  
...  

ABSTRACT No genome sequence of a species from Barnettozyma, a yeast genus in the family Phaffomycetaceae, is currently available. We isolated two B. californica strains from soils in Ireland and generated draft sequences of their 11.7-Mb genomes. Single nucleotide polymorphism (SNP) analysis showed 20,490 differences between the strains and suggests that B. californica is haploid.


2015 ◽  
Vol 53 (4) ◽  
pp. 1227-1238 ◽  
Author(s):  
Erika Scaltriti ◽  
Davide Sassera ◽  
Francesco Comandatore ◽  
Marina Morganti ◽  
Carmen Mandalari ◽  
...  

We retrospectively analyzed a rareSalmonella entericaserovar Manhattan outbreak that occurred in Italy in 2009 to evaluate the potential of new genomic tools based on differential single nucleotide polymorphism (SNP) analysis in comparison with the gold standard genotyping method, pulsed-field gel electrophoresis. A total of 39 isolates were analyzed from patients (n= 15) and food, feed, animal, and environmental sources (n= 24), resulting in five different pulsed-field gel electrophoresis (PFGE) profiles. Isolates epidemiologically related to the outbreak clustered within the same pulsotype, SXB_BS.0003, without any further differentiation. Thirty-three isolates were considered for genomic analysis based on different sets of SNPs, core, synonymous, nonsynonymous, as well as SNPs in different codon positions, by Bayesian and maximum likelihood algorithms. Trees generated from core and nonsynonymous SNPs, as well as SNPs at the second and first plus second codon positions detailed four distinct groups of isolates within the outbreak pulsotype, discriminating outbreak-related isolates of human and food origins. Conversely, the trees derived from synonymous and third-codon-position SNPs clustered food and human isolates together, indicating that all outbreak-related isolates constituted a single clone, which was in line with the epidemiological evidence. Further experiments are in place to extend this approach within our regional enteropathogen surveillance system.


2020 ◽  
Vol 58 (5) ◽  
Author(s):  
Paul Chapman ◽  
Brian M. Forde ◽  
Leah W. Roberts ◽  
Haakon Bergh ◽  
Debra Vesey ◽  
...  

ABSTRACT Klebsiella species are problematic pathogens in neonatal units and may cause outbreaks, for which the sources of transmission may be challenging to elucidate. We describe the use of whole-genome sequencing (WGS) to investigate environmental sources of transmission during an outbreak of extended-spectrum-β-lactamase (ESBL)-producing Klebsiella michiganensis colonizing neonates. Ceftriaxone-resistant Klebsiella spp. isolated from neonates (or their mothers) and the hospital environment were included. Short-read sequencing (Illumina) and long-read sequencing (MinION; Oxford Nanopore Technologies) were used to confirm species taxonomy, to identify antimicrobial resistance genes, and to determine phylogenetic relationships using single-nucleotide polymorphism profiling. A total of 21 organisms (10 patient-derived isolates and 11 environmental isolates) were sequenced. Standard laboratory methods identified the outbreak strain as an ESBL-producing Klebsiella oxytoca, but taxonomic assignment from WGS data suggested closer identity to Klebsiella michiganensis. Strains isolated from multiple detergent-dispensing bottles were either identical or closely related by single-nucleotide polymorphism comparison. Detergent bottles contaminated by K. michiganensis had been used for washing milk expression equipment. No new cases were identified once the detergent bottles were removed. Environmental reservoirs may be an important source in outbreaks of multidrug-resistant organisms. WGS, in conjunction with traditional epidemiological investigation, can be instrumental in revealing routes of transmission and guiding infection control responses.


2018 ◽  
Vol 43 (4) ◽  
pp. 309
Author(s):  
N. Hilmia ◽  
D. Rahmat ◽  
D. Dudi

Point mutation on exon 2 of leptin gene, which changes amino acid encoding from Arginine to Cysteine, may alters the physiological function of the leptin hormone. This study aimed to identify leptin gene polymorphism of Ongole Grade (OG) cattle based on Single Nucleotide Polymorphism (SNP). The DNA sample was taken from 48 head of OG cattle at Balai Pengembangan Perbibitan Ternak Sapi Potong(BPPT SP) Cijeungjing West Java, which was isolated from white blood cell using the high salt method. Amplification of DNA was done by Polymerase Chain Reaction (PCR), followed by direct sequencing to obtain nucleotide sequence. The SNP analysis was carried out from alignment of sequencing result using Bioedit and MEGA 5.2 program. The results indicated in exon 2 leptin gene of OG cattle there was one synonymous SNPs that did not changeamino acids Serine encoding on g.1025T >C/S17S, while two non synonymous SNPaltered amino acids encoding, those were g.1047C> T /R25C and g.1048G>A/R25H. Those mutations changed amino acids encoding from Arginine to Cysteine and Arginine to Histidine respectively.In OG cattle, the frequency of A allele (44.8%) was higher than C allele (33.3%) and T allele (21.9%). Six genotypes were also identified, i.e. AA (41.7%), CC (20.8%), CT (20.8%), CA(4.2%), TT (10.4%) and TA (2.1 %). Heterozigosity of OG cattle based on leptin gene was 0.65 that was a high category. The A allele was a specific allele on Indonesian local cattle.


Stroke ◽  
2020 ◽  
Vol 51 (8) ◽  
pp. 2454-2463
Author(s):  
Keith L. Keene ◽  
Hyacinth I. Hyacinth ◽  
Joshua C. Bis ◽  
Steven J. Kittner ◽  
Braxton D. Mitchell ◽  
...  

Background and Purpose: Stroke is a complex disease with multiple genetic and environmental risk factors. Blacks endure a nearly 2-fold greater risk of stroke and are 2× to 3× more likely to die from stroke than European Americans. Methods: The COMPASS (Consortium of Minority Population Genome-Wide Association Studies of Stroke) has conducted a genome-wide association meta-analysis of stroke in >22 000 individuals of African ancestry (3734 cases, 18 317 controls) from 13 cohorts. Results: In meta-analyses, we identified one single nucleotide polymorphism (rs55931441) near the HNF1A gene that reached genome-wide significance ( P =4.62×10 −8 ) and an additional 29 variants with suggestive evidence of association ( P <1×10 −6 ), representing 24 unique loci. For validation, a look-up analysis for a 100 kb region flanking the COMPASS single nucleotide polymorphism was performed in SiGN (Stroke Genetics Network) Europeans, SiGN Hispanics, and METASTROKE (Europeans). Using a stringent Bonferroni correction P value of 2.08×10 −3 (0.05/24 unique loci), we were able to validate associations at the HNF1A locus in both SiGN ( P =8.18×10 −4 ) and METASTROKE ( P =1.72×10 −3 ) European populations. Overall, 16 of 24 loci showed evidence for validation across multiple populations. Previous studies have reported associations between variants in the HNF1A gene and lipids, C-reactive protein, and risk of coronary artery disease and stroke. Suggestive associations with variants in the SFXN4 and TMEM108 genes represent potential novel ischemic stroke loci. Conclusions: These findings represent the most thorough investigation of genetic determinants of stroke in individuals of African descent, to date.


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