Intron polymorphism in small subunit rDNA of Nectria galligena.
PCR amplification of the small subunit (SSU) rDNA gene of 40 isolates of Nectria galligena revealed four length polymorphisms. PCR-RFLP analysis of the SSU rDNA gene divided the isolates into four categories similar, but not identical, to categories identified by Southern-RFLP analysis. Nucleotide sequence analysis revealed that isolates in three of the four SSU rDNA (18S) categories possess an intron of 363 bp, 1185 bp or 1423 bp at the NS 7 priming site. Isolates in the fourth category do not possess an intron. The nucleotide sequences of these introns did not contain the core elements characteristic of typical group I introns, nor did they exhibit a group I intron secondary structure. Homology between the introns indicates a common lineage, all three possibly having come from a larger intron and having been formed by subsequent deletions. PCR primers upstream of the SSU rDNA intron region and from within the internal transcribed spacer 1 region amplify a product specific to N. galligena, which will confirm the identity of the pathogen and reveal its 18S category in a single reaction.
Crockard
M A
MA
Applied Plant Science Division, Department of Agriculture for Northern Ireland and Newforge LaneBelfast BT9 5PXUK.
Fulton
C E
CE
Department of Applied Plant Science, The Queen's University of BelfastAgriculture and Food Science Centre, Newforge Lane, Belfast BT9 5PXUK.
Bjourson
A J
AJ
Applied Plant Science Division, Department of Agriculture for Northern Ireland and Newforge LaneBelfast BT9 5PXUK.
Brown
Averil E
AE
Department of Applied Plant Science, The Queen's University of BelfastAgriculture and Food Science Centre, Newforge Lane, Belfast BT9 5PXUK.
D004271:DNA, Fungal / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D015246:Deoxyribonuclease EcoRI; D005784:Gene Amplification; D006999:Hypocreales; D007438:Introns / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012337:RNA, Ribosomal, 18S / Q000235:genetics
D004271:DNA, Fungal; D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D015246:Deoxyribonuclease EcoRI