Hostname: page-component-788cddb947-nxk7g Total loading time: 0 Render date: 2024-10-13T13:58:19.248Z Has data issue: false hasContentIssue false

Optional mitochondrial introns and evidence for a homing-endonuclease gene in the mtDNA rnl gene in Ophiostoma ulmi s. lat.

Published online by Cambridge University Press:  22 September 2005

Ewan A. GIBB
Affiliation:
Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada. E-mail: hausnerg@cc.umanitoba.ca
Georg HAUSNER
Affiliation:
Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada. E-mail: hausnerg@cc.umanitoba.ca
Get access

Abstract

Strains of Ophiostoma ulmi, O. novo-ulmi subsp. americana, O. novo-ulmi subsp. novo-ulmi and O. himal-ulmi were examined for optional introns/insertions within the following mitochondrial genes: small subunit RNA gene (rns), large ribosomal subunit gene (rnl) and the cytochrome oxidase subunit I gene (coxI). Insertions were noted in the rns and coxI genes in strains of O. ulmi, the less aggressive species, but absent in strains of the more aggressive O. novo-ulmi subsp. americana. Strains of all species examined had a group I intron present in the U11 region of the mitochondrial-rnl gene. In all but two strains of O. novo-ulmi subsp. americana, this rnl-U11 intron was about 1.5 kb in length whereas a 2.6 kb version of this element was present in all strains representing O. ulmi, O. novo-ulmi subsp. novo-ulmi, and Ophiostoma himal-ulmi. Irrespective of size, this intron based on RNA folds is a class IA1 group I intron and it encodes a putative ORF for the rps3 ribosomal protein. The size variation of the rnl-U11 intron was examined in detail for two strains of O. novo-ulmi subsp. americana and sequence data suggests the presence of a complex ORF within the 2.6 kb version of this intron; here a homing endonuclease-like gene has been inserted in frame and fused to the carboxyl-terminus of the putative rps3 coding region. The mitochondrial optional introns/insertions in combination with nuclear markers might be useful in distinguishing among the various species and subspecies of the O. ulmi s. lat. complex.

Type
Research Article
Copyright
© The British Mycological Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)