scholarly journals Substrate Specificity-Conferring Regions of the Nonribosomal Peptide Synthetase Adenylation Domains Involved in Albicidin Pathotoxin Biosynthesis Are Highly Conserved within the Species Xanthomonas albilineans

2007 ◽  
Vol 73 (17) ◽  
pp. 5523-5530 ◽  
Author(s):  
Adeline Renier ◽  
Eric Vivien ◽  
Stéphane Cociancich ◽  
Philippe Letourmy ◽  
Xavier Perrier ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Amino Acid ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Leaf Scald ◽  
Peptide Synthetase ◽  
A Domains ◽  
Xanthomonas Albilineans

ABSTRACT Albicidin is a pathotoxin produced by Xanthomonas albilineans, a xylem-invading pathogen that causes leaf scald disease of sugarcane. Albicidin is synthesized by a nonribosomal pathway via modular polyketide synthase and nonribosomal peptide synthetase (NRPS) megasynthases, and NRPS adenylation (A) domains are responsible for the recognition and activation of specific amino acid substrates. DNA fragments (0.5 kb) encoding the regions responsible for the substrate specificities of six albicidin NRPS A domains from 16 strains of X. albilineans representing the known diversity of this pathogen were amplified and sequenced. Polymorphism analysis of these DNA fragments at different levels (DNA, protein, and NRPS signature) showed that these pathogenicity loci were highly conserved. The conservation of these loci most likely reflects purifying selective pressure, as revealed by a comparison with the variability of nucleotide and amino acid sequences of two housekeeping genes (atpD and efp) of X. albilineans. Nevertheless, the 16 strains of X. albilineans were differentiated into several groups by a phylogenetic analysis of the nucleotide sequences corresponding to the NRPS A domains. One of these groups was representative of the genetic diversity previously found within the pathogen by random fragment length polymorphism and amplified fragment length polymorphism analyses. This group, which differed by three single synonymous nucleotide mutations, contained only four strains of X. albilineans that were all involved in outbreaks of sugarcane leaf scald. The amount of albicidin produced in vitro in agar and liquid media varied among the 16 strains of X. albilineans. However, no relationship among the amount of albicidin produced in vitro and the pathotypes and genetic diversity of the pathogen was found. The NRPS loci contributing to the synthesis of the primary structure of albicidin apparently are not involved in the observed pathogenicity differences among strains of X. albilineans.

scholarly journals Variation in Albicidin Biosynthesis Genes and in Pathogenicity of Xanthomonas albilineans, the Sugarcane Leaf Scald Pathogen

2006 ◽  
Vol 96 (1) ◽  
pp. 33-45 ◽  
Author(s):  
P. Champoiseau ◽  
J.-H. Daugrois ◽  
J.-C. Girard ◽  
M. Royer ◽  
P. C. Rott
Keyword(s):  
Genetic Diversity ◽  
Fragment Length Polymorphism ◽  
Pathogen Population ◽  
Biosynthesis Gene Cluster ◽  
Leaf Scald ◽  
Genetic Groups ◽  
Biosynthesis Gene ◽  
Genomic Regions ◽  
Xanthomonas Albilineans

Total genomic DNA from 137 strains of Xanthomonas albilineans from worldwide locations was hybridized with two DNA probes that together harbor the entire 49-kb albicidin biosynthesis gene cluster and two additional 3-kb genomic regions required for albicidin production. Fourteen haplotypes and two major genetic groups (albicidin [ALB]-restriction fragment length polymorphism [RFLP] A and ALB-RFLP B) were identified, and strains that were isolated after recent outbreaks of leaf scald disease belonged to group ALB-RFLP B. Albicidin genetic diversity was very similar to the previously described genetic diversity of the pathogen based on the whole genome. No relationship was found between variability of albicidin biosynthesis genes and the amount of albicidin produced in vitro by X. albilineans. Leaf scald-susceptible sugarcane cv. H70-144 was inoculated with 20 strains of the pathogen belonging to different ALB-RFLP haplotypes. Among them, 10 strains from Guadeloupe belonged to the same ALB-RFLP group but differed in the amount of albicidin produced in vitro. Strains were distributed in at least three different pathogenicity groups based on symptom severity and pathogen population density in the stalk. These two pathogenicity factors varied concurrently; however, no relationship between variation in albicidin biosynthesis genes, variation in the amount of albicidin produced in vitro, and variation in pathogenicity of X. albilineans was found. Further investigation is necessary to identify other genes involved in pathogenicity of X. albilineans.

scholarly journals High Variation in Pathogenicity of Genetically Closely Related Strains of Xanthomonas albilineans, the Sugarcane Leaf Scald Pathogen, in Guadeloupe

2006 ◽  
Vol 96 (10) ◽  
pp. 1081-1091 ◽  
Author(s):  
P. Champoiseau ◽  
J.-H. Daugrois ◽  
I. Pieretti ◽  
S. Cociancich ◽  
M. Royer ◽  
...  
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Molecular Mechanisms ◽  
Fragment Length Polymorphism ◽  
Bacterial Species ◽  
Vascular Plant ◽  
Genomic Variation ◽  
Phylogenetic Study ◽  
Leaf Scald ◽  
Xanthomonas Albilineans

Pathogenicity of 75 strains of Xanthomonas albilineans from Guadeloupe was assessed by inoculation of sugarcane cv. B69566, which is susceptible to leaf scald, and 19 of the strains were selected as representative of the variation in pathogenicity observed based on stalk colonization. In vitro production of albicidin varied among these 19 strains, but the restriction fragment length polymorphism pattern of their albicidin biosynthesis genes was identical. Similarly, no genomic variation was found among strains by pulsed-field gel electrophoresis. Some variation among strains was found by amplified fragment length polymorphism, but no relationship between this genetic variation and variation in pathogenicity was found. Only 3 (pilB, rpfA, and xpsE) of 40 genes involved in pathogenicity of bacterial species closely related to X. albilineans could be amplified by polymerase chain reaction from total genomic DNA of all nine strains tested of X. albilineans differing in pathogenicity in Guadeloupe. Nucleotide sequences of these genes were 100% identical among strains, and a phylogenetic study with these genes and housekeeping genes efp and ihfA suggested that X. albilineans is on an evolutionary road between the X. campestris group and Xylella fastidiosa, another vascular plant pathogen. Sequencing of the complete genome of Xanthomonas albilineans could be the next step in deciphering molecular mechanisms involved in pathogenicity of X. albilineans.

scholarly journals Fluorescent amplified fragment length polymorphism (fAFLP) analyses and genetic diversity in Litopenaeus vannamei (Penaeidae)

2005 ◽  
Vol 28 (2) ◽  
pp. 267-270 ◽  
Author(s):  
Michelle Mantovani Gonçalves ◽  
Manoel Victor Franco Lemos ◽  
Pedro Manoel Galetti Junior ◽  
Patrícia Domingues de Freitas ◽  
Manuel Antonio Andrade Furtado Neto
Keyword(s):  
Genetic Diversity ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Litopenaeus Vannamei ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism

Genetic diversity of fringed brome (Bromus ciliatus) as determined by amplified fragment length polymorphism

2005 ◽  
Vol 83 (10) ◽  
pp. 1322-1328 ◽  
Author(s):  
Yong-Bi Fu ◽  
Bruce E. Coulman ◽  
Yasas S.N. Ferdinandez ◽  
Jacques Cayouette ◽  
Paul M. Peterson
Keyword(s):  
Genetic Diversity ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Habitat Restoration ◽  
Fragment Length Polymorphism ◽  
Natural Populations ◽  
Germplasm Conservation ◽  
Amplified Fragment Length Polymorphism ◽  
Large Area ◽  
Geographic Origins

Fringed brome ( Bromus ciliatus L.) is found in native stands throughout a large area of North America. Little is known about the genetic diversity of this species. The amplified fragment length polymorphism (AFLP) technique was applied to assess the genetic diversity of 16 fringed brome populations sampled in Canada from the provinces of Alberta, British Columbia, Quebec, and Saskatchewan. Four AFLP primer pairs were employed to screen 82 samples with four to six samples per population and 83 polymorphic AFLP bands scored for each sample. The frequencies of the scored bands in all assayed samples ranged from 0.01 to 0.99 and averaged 0.53. Analysis of molecular variance revealed that 52.6% of the total AFLP variation resided among the 16 populations and 20.6% among the four provinces. The five Quebec populations appeared to be genetically the most diverse and distinct. The AFLP variability observed was significantly associated with the geographic origins of the fringed brome populations. These findings are useful for sampling fringed brome germplasm from natural populations for germplasm conservation and should facilitate the development of genetically diverse regional cultivars for habitat restoration and revegetation.

scholarly journals Genetic Diversity of Rhubarb Cultivars

2008 ◽  
Vol 133 (4) ◽  
pp. 587-592 ◽  
Author(s):  
Joseph C. Kuhl ◽  
Veronica L. DeBoer
Keyword(s):  
Genetic Diversity ◽  
Central Asia ◽  
Length Polymorphism ◽  
Genetic Relationship ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
18Th Century ◽  
Pedigree Information ◽  
Aflp Analysis ◽  
Fingerprint Analysis

The genus Rheum L., commonly known as rhubarb, is composed of ≈60 species, primarily distributed throughout northern and central Asia. Rhubarb species have been used for medicinal purposes for thousands of years; however, it was not until the 18th century that the culinary use of petioles was first reported. Although the origin(s) of culinary rhubarb is not clear, it is thought that they originated from hybridization of rhubarb species originally brought to Europe for medicinal purposes. Most rhubarb cultivars lack pedigree information, and the genetic relationship among cultivars is largely unknown. Amplified fragment length polymorphism (AFLP) markers were generated for fingerprint analysis of 37 cultivars and four putative Rheum species accessions. Ten EcoRI and MseI primer combinations were analyzed for a total of 1400 scored polymorphisms, with an average of 140 polymorphisms per primer combination. Results show at least two clusters of related cultivars, as well as distantly related accessions. This study provides an estimate of rhubarb cultivar genetic diversity using AFLP analysis.

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