Ecotypic variation of Gremmeniella abietina in northern Europe: disease patterns reflected by DNA variation

1995 ◽  
Vol 73 (10) ◽  
pp. 1531-1539 ◽  
Author(s):  
M. Hellgren ◽  
N. Högberg

Genetic variation in Gremmeniella abietina isolated from Pinus sylvestris, Pinus contorta, and Picea abies in southern and northern Fennoscandia was studied with arbitrary primed polymerase chain reaction. Fennoscandian G. abietina isolates were clearly separated into two ecotypically distinct groups based on their amplified banding patterns. Analysis of variance based on amplified fragments, AMOVA, and principal component analysis confirmed the separation of the isolates into the two groups. One group contained isolates associated with a disease syndrome affecting young trees covered by deep snow during winter in northern Fennoscandia. The second group of isolates was found on trees between 15 and 40 years old, scattered throughout the crowns. It occurs throughout Fennoscandia but is most frequent in the southern parts. No size polymorphism was found in fragments resulting after restriction enzyme digestion of internal transcribed spacer and intergenic spacer regions of nuclear ribosomal DNA. An estimate of gene flow between populations calculated based on amplified band frequencies, FST, indicated that there was restricted genetic exchange between populations of the two groups of isolates. Key words: Gremmeniella abietina, arbitrary primed polymerase chain reaction, genetic variation, ecotypes, ribosomal DNA.

Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 664-671 ◽  
Author(s):  
Lang Zhuo ◽  
S. L. Sajdak ◽  
R. B. Phillips

Intraspecific variation in the sequence of the transcribed spacer regions of the ribosomal DNA (rDNA) in lake trout was examined by restriction mapping and sequencing of these regions amplified by the polymerase chain reaction. The length of the first internal transcribed spacer region (ITS-1) was 566 bases and the second internal transcribed spacer region (ITS-2) was 368 bases in lake trout. When the 1.4-kb region including the ITS-1, the 5.8S coding region, and the ITS-2 was amplified from 12 individuals from four populations and digested with eight different enzymes only one intraindividual polymorphism was found that occurred in each population. When the amplified ITS-1 region was sequenced from an additional 10 individuals from five populations, no interindividual variation was found in the sequence. A 6-kb portion of the rDNA repeat unit including 1.6 kb of the 18S coding region, the 5′ external spacer region (5′ ETS), and part of the adjacent intergenic spacer was cloned and a restriction map was prepared for these regions in lake trout. No intraspecific variation was found in the region adjacent to the 18S rDNA, which includes the 5′ ETS, although intraspecific and intraindividual length variation was found in the intergenic spacer region 3–6 kb from the 18S. Sequencing of a 609-b segment of the 5′ ETS adjacent to the 18S coding region revealed the presence of two 41-b repeats. The 198-b sequence between the repeats had some similarity to the 18S coding region of other fishes. Primers were designed for amplification of 559 b of the 5′ ETS using the polymerase chain reaction. No intraspecific variation in this region in lake trout was found when the DNA amplified from this region in 12 individuals from four populations was digested with eight restriction enzymes.Key words: ribosomal DNA, internal transcribed spacer regions, 5′ external spacer region, transcribed spacer, lake trout.


2007 ◽  
Vol 19 (5) ◽  
pp. 532-534 ◽  
Author(s):  
John A. Angelos ◽  
Louise M. Ball

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.


Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 686-693 ◽  
Author(s):  
Benoit Van Coppenolle ◽  
Iwao Watanabe ◽  
Charles Van Hove ◽  
Gerard Second ◽  
Ning Huang ◽  
...  

The polymerase chain reaction was used to amplify random sequences of DNA from 25 accessions of Azolla to evaluate the usefulness of this technique for identification and phylogenetic analysis of this aquatic fern. Accessions were selected to represent all known species within the genus Azolla and to encompass the worldwide distribution of the fern. Primers of 10 nucleotides with 70% G + C content were used to generate randomly amplified polymorphic DNA from the symbiotic Azolla–Anabaena complex. Twenty-two primers were used and each primer gave 4–10 bands of different molecular weights for each accession. Bands were scored as present or absent for each accession and variation among accessions was quantified using Nei's genetic distances. A dendrogram summarizing phenetic relationships among the 25 accessions was generated using the unweighted pair-group method with arithmetic mean. Principal component analysis was also used to evaluate genetic similarities. Three distinct groups were identified: group 1 contains five species, group 2 contains the pinnata species, and group 3 contains the nilotica species. The analysis demonstrates that the major groups of Azolla species can be easily distinguished from one an other and, in addition, that closely related accessions within species can be identified. We further found that using 10 primers, a phylogeny that is essentially the same as that derived from 22 primers can be constructed. Our results suggest that total DNA extracted from the Azolla–Anabaena symbionts is useful for classification and phylogenetic studies of Azolla.Key words: Azolla–Anabaena symbiosis, genetic distances, polymerase chain reaction, principal component analysis.


Author(s):  
J. Albertyn ◽  
K.M. Tajbhai ◽  
R.R. Bragg

Psittacine beak and feather disease (PBFD) is a common disease of the psittacine species and is caused by the psittacine beak and feather disease virus (PBFDV). In this study the occurrence of the disease in ring-neck parakeets and budgerigars in South Africa suffering from feathering problems, using polymerase chain reaction as a diagnostic test was investigated. The genetic variation between viral isolates was also studied. Results indicate that PBFDV can be attributed to being the cause of feathering problems in some of the ring-neck parakeets and budgerigars in South Africa. Genetic variation of isolates occurs between species and individuals. A cheap and easy to use method of blood sample collection on filter paper for diagnostic purposes was also evaluated. It proved to be less stressful to the birds and did not inhibit further processes.


Sign in / Sign up

Export Citation Format

Share Document