The Complete DNA Sequence of the Nuclear Ribosomal RNA Gene Complex of Verticillium dahliae: Intraspecific Heterogeneity within the Intergenic Spacer Region

Using PCR-based assays with specific primers for amplification of the ribosomal DNA intergenic spacer region (IGS) and a portion of the mitochondrial DNA small subunit ribosomal RNA gene (mtDNA SSU rRNA), the genetic variability among Verticillium dahliae isolates from olive (Olea europaea) and other host species from Argentina and Brazil was estimated. The derived UPGMA-generated phenograms based upon the restriction fingerprinting data of rDNA IGS products revealed genetic differences, correlating with the host of origin. Isolates infecting olive genetically distinct from those from cocoa (Theobroma cacao) and sunflower (Helianthus annuus). Digestion of mitochondrial DNA SSU rRNA PCR products revealed less variability, distinguishing only one isolate from sunflower. Ribosomal DNA ITS restriction patterns were identical for all isolates of V. dahliae, irrespective of host of origin. These preliminary results may have relevance for Verticillium wilt control practices, possibly reflecting a different evolutionary origin, or reproductive isolation of the pathogen in olive, distinct from populations of other hosts.

Download Full-text

The Nor-D3 locus of Triticum tauschii: natural variation and genetic linkage to markers in chromosome 5

Genome ◽

10.1139/g91-060 ◽

1991 ◽

Vol 34 (3) ◽

pp. 387-395 ◽

Cited By ~ 75

Author(s):

E. S. Lagudah ◽

R. Appels ◽

D. McNeil

Keyword(s):

Ribosomal Rna ◽

Intergenic Spacer ◽

D Genome ◽

Triticum Tauschii ◽

Intergenic Spacer Region ◽

Grain Softness ◽

High Level ◽

Rna Genes ◽

Rdna Polymorphism ◽

Grain Softness Protein

Variation in the intergenic spacer region of the ribosomal RNA genes (located at the Nor locus) was assayed in a collection of 411 accessions of Triticum tauschii from Turkey, USSR, Iran, Afghanisan, Pakistan, and China. Twenty rDNA genotypes were identified and it was demonstrated that T. tauschii accessions from the USSR and Iran have the highest diversity at the Nor locus. At least four of the rDNA genotypes were demonstrated to be alleles of a single major locus, in segregating F2 progeny analyses. The TaqI restriction fragment associated with rDNA genotype 7 was shown to be the same as the Nor-D3a allele present in all bread wheats (based on chromosome location and length of the intergenic spacer region). This genotype was significantly associated with T. t. ssp. strangulata, previously argued to be the donor of the D genome to hexaploid wheat. The Nor locus showed a high level of recombination with the 5SDna-2 locus, which was also located on chromosome 5D. The Nor locus is placed distal to the 5SDna-2 locus but proximal to the grain softness protein gene (XGsp) on the short arm of chromosome 5D.Key words: D genome, Nor-D3, rDNA polymorphism, chromosomal location.

Download Full-text

Fluconazole-Resistant PathogensCandida inconspicuaandC. norvegensis: DNA Sequence Diversity of the rRNA Intergenic Spacer Region, Antifungal Drug Susceptibility, and Extracellular Enzyme Production

Microbiology and Immunology ◽

10.1111/j.1348-0421.2004.tb03602.x ◽

2004 ◽

Vol 48 (10) ◽

pp. 761-766 ◽

Cited By ~ 15

Author(s):

Takashi Sugita ◽

Kanji Takeo ◽

Misako Ohkusu ◽

Eric Virtudazo ◽

Masako Takashima ◽

...

Keyword(s):

Dna Sequence ◽

Enzyme Production ◽

Intergenic Spacer ◽

Extracellular Enzyme ◽

Drug Susceptibility ◽

Sequence Diversity ◽

Antifungal Drug ◽

Intergenic Spacer Region ◽

Fluconazole Resistant

Download Full-text

Differentiation of Moraxella Bovoculi sp. nov. from other Coccoid Moraxellae by the Use of Polymerase Chain Reaction and Restriction Endonuclease Analysis of Amplified DNA

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870701900511 ◽

2007 ◽

Vol 19 (5) ◽

pp. 532-534 ◽

Cited By ~ 18

Author(s):

John A. Angelos ◽

Louise M. Ball

Keyword(s):

Polymerase Chain Reaction ◽

Dna Sequence ◽

Restriction Analysis ◽

Intergenic Spacer ◽

Restriction Enzyme Digestion ◽

Chain Reaction ◽

Gram Negative ◽

Intergenic Spacer Region ◽

Polymerase Chain ◽

Moraxella Bovoculi

Moraxella oris was historically the only coccoid Moraxella identified in cultures of ocular fluid from cattle with infectious bovine keratoconjunctivitis (IBK) and could be morphologically and biochemically differentiated from Moraxella bovis. Moraxella bovoculi sp. nov. is a recently characterized Moraxella isolated from ulcerated eyes of calves with IBK in northern California in 2002. Like Moraxella ovis, M. bovoculi sp. nov. is a gram-negative coccus/diplococcus. All 18 original isolates of M. bovoculi sp. nov. possessed phenylalanine deaminase (PADase) activity and could therefore be differentiated from M. ovis and M. bovis. During the characterization of 44 additional isolates of hemolytic gram-negative cocci that were cultured from ulcerated eyes of IBK-affected calves, 2 PADase-negative isolates were identified that could not be differentiated biochemically from M. ovis; however, the DNA sequence of the 16S-23S intergenic spacer region (ISR) of the isolates matched the 16S-23S ISR DNA sequence of M. bovoculi sp. nov. To facilitate the identification of PADase-negative moraxellae, a polymerase chain reaction (PCR) coupled with restriction enzyme digestion analysis of amplified DNA was developed. Amplification of the 16S-23S ISR followed by AfaI digestion of amplified DNA could differentiate M. bovoculi sp. nov. from M. ovis and other moraxellae. The DNA sequence analysis of the amplified 16S-23S ISR from the 42 PADase-positive isolates of hemolytic gram-negative cocci indicated that all were M. bovoculi sp. nov. and all possessed an AfaI site. A PCR coupled with restriction analysis of amplified DNA can aid in identifying M. bovoculi sp. nov.

Download Full-text