Intron polymorphism in small subunit rDNA of Nectria galligena

Crockard, Martin; Fulton, C. E.; Bjourson, Anthony J.; Brown, Averil E.

doi:10.1099/00221287-144-8-2367

Cited by 11 publications

(6 citation statements)

References 18 publications

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“…An alternative approach is to target the small subunit (SSU, 18S) rDNA gene and analyse 18S sequence variation among the fungal isolates using denaturing gradient gel electrophoresis (DGGE; Lessa, 1992; Vainio and Hantula, 2000). Although the 18S rDNA gene is highly conserved in nature, several studies have reported intraspecific variation within introns occurring in the gene (Crockard et al., 1998). Microsatellite‐primed PCR (MP‐PCR) has also been used successfully in species and subspecies differentiation in many pathogenic fungal genera (Czembor and Arseniuk, 1999), including Colletotrichum (Freeman et al., 1996).…”

Section: Introductionmentioning

confidence: 99%

Two Genetically Distinct Populations of Colletotrichum gloeosporioides Penz. Causing Anthracnose Disease of Yam (Dioscorea spp.)

Abang¹,

Fagbola²,

Smalla³

et al. 2005

Journal of Phytopathology

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Variation within Colletotrichum gloeosporioides, the causal agent of yam anthracnose disease, is still poorly defined and this hinders breeding for resistance. Two morphotypes of C. gloeosporioides, designated slowgrowing grey (SGG) and fast-growing salmon (FGS), are associated with anthracnose disease of yam in Nigeria. The morphotypes are distinguishable based on colony and conidial morphology, growth rate, virulence, as well as vegetative compatibility, but molecular differentiation of SGG and FGS strains is needed to facilitate epidemiological studies. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified small subunit (18S) rDNA fragments, and microsatellite-primed PCR (MP-PCR) genomic fingerprinting were employed to provide a basis for molecular differentiation of the morphotypes. DGGE analysis revealed patterns that clearly differentiated isolates of the aggressive defoliating SGG from the moderately virulent non-defoliating FGS strains. Genetic analysis based on 52 MP-PCR markers revealed highly significant differentiation between the SGG and FGS populations on yam (G ST ¼ 0.22; Nei's genetic identity ¼ 0.85; h ¼ 0.28, P < 0.001), indicating that the SGG and FGS morphotypes represent genetically differentiated populations. The results of the molecular typing using DGGE and MP-PCR analyses were consistent with the disease phenotype caused by the two morphotypes. Consequently, these molecular techniques might be used, at least partly, to replace time-consuming virulence studies on yam.

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Section: Introductionmentioning

confidence: 99%

Two Genetically Distinct Populations of Colletotrichum gloeosporioides Penz. Causing Anthracnose Disease of Yam (Dioscorea spp.)

Abang¹,

Fagbola²,

Smalla³

et al. 2005

Journal of Phytopathology

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“…Group I introns have been characterized from the nuclear small subunit (nuSSU) rRNA gene of the Ascomycete fungi Pneumocystis carinii (Sogin and Edman 1989) and Nectria galligena (Crockard et al 1998). Single nuSSU rRNA group I intron sequences have been identified for B. bassiana (Suh et al 2001; GenBank AF280633) and B. brongniartii (Nikoh and Fukatsu 2000; GenBank AB027335), but intron structure and population diversity were not defined.…”

Section: Introductionmentioning

confidence: 99%

Nuclear small subunit rRNA group I intron variation among Beauveria spp provide tools for strain identification and evidence of horizontal transfer

2002

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An optional group I intron was characterized at a single insertion point in nuclear small subunit rRNA (nuSSU rRNA) genes of the imperfect entomopathogenic fungi, Beauveria bassiana and B. brongniartii. Insertion points were conserved among nuSSU rRNA genes from 35 Beauveria isolates. PCR-RFLP and DNA sequencing identified 12 group I intron variants and were applied to the identification of strains isolated from insect hosts. Alignment of 383-404-nt subgroup IB3 group I introns indicated that four insertion/deletion (indel) mutations were the main basis of fragment length variation. Phylogeny reconstruction using parsimony and neighbor-joining methods suggested six lineages may be present among nuSSU rRNA group I intron sequences from Beauveria and related ascomycete fungi. Terminal node placement of Beauveria introns conflicted with previously published phylogenies constructed from gene sequences, suggesting horizontal transfer of group I introns. PCRRFLP among introns provided a means for the differentiation of Beauveria isolates. Abstract An optional group I intron was characterized at a single insertion point in nuclear small subunit rRNA (nuSSU rRNA) genes of the imperfect entomopathogenic fungi, Beauveria bassiana and B. brongniartii. Insertion points were conserved among nuSSU rRNA genes from 35 Beauveria isolates. PCR-RFLP and DNA sequencing identified 12 group I intron variants and were applied to the identification of strains isolated from insect hosts. Alignment of 383-404-nt subgroup IB3 group I introns indicated that four insertion/deletion (indel) mutations were the main basis of fragment length variation. Phylogeny reconstruction using parsimony and neighbor-joining methods suggested six lineages may be present among nuSSU rRNA group I intron sequences from Beauveria and related ascomycete fungi. Terminal node placement of Beauveria introns conflicted with previously published phylogenies constructed from gene sequences, suggesting horizontal transfer of group I introns. PCR-RFLP among introns provided a means for the differentiation of Beauveria isolates.

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“…These include two Cryphonectra introns (2) and an intron from Tillrtiopsis flava (15). The fact that similar group IC4 introns are found in distantly related eukaryotic micro-organisms suggests that the Nectria 363 intron, in contrast to what was suggested by Crockard et al (3), has been gained by horizontal transfer during evolution.…”

mentioning

confidence: 76%

“…We have re-analysed the Nectria sequences reported by Crockard et al (3) and discovered that the smallest insertion (the 363 intron) contains a typical group I intron structure (Fig. la).…”

mentioning

confidence: 90%