Record Details
RFLP analysis of genetic variation in the laminated-root-rot fungal pathogen of conifers, Phellinus weirii
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | RFLP analysis of genetic variation in the laminated-root-rot fungal pathogen of conifers, Phellinus weirii |
| Names |
Bae, Hanhong
(creator) Hansen, Everett M. (advisor) |
| Date Issued | 1992-04-24 (iso8601) |
| Note | Graduation date: 1993 |
| Abstract | DNA markers that detect polymorphisms within and between two biological species of the coniferous laminated-root-rot fungus Phellinus weirii were developed and used to measure the amount and distribution of genetic variation. In a preliminary survey, total cellular DNA from 3 Douglas-fir-type isolates and 3 cedar-type isolates was digested with 12 restriction enzymes, gel-blotted, and probed with 16 random genomic clones derived from total cellular DNA of Phellinus weirii; one cloned nuclear ribosomal gene from Coprinus cinereus; and three cloned mitochondrial genes from Suillus sinuspaulianus. Our results were consistent with previous studies in that the two biological species were different in most characteristics (91% of probe-enzyme combinations differed between the two biological species). Polymorphisms within biological species were also detected with several probe-enzyme combinations (11.5% for the cedar type, and 14.4% for the Douglas-fir type). While ribosomal DNA of the fungus was polymorphic within and between biological species, mitochondrial DNA was monomorphic within, though polymorphic between biological species. One random genomic clone, pPW13, revealed a multiple-banded "DNA fingerprinting" type of fragment phenotype in the Douglas-fir type. Twenty-seven isolates representing 6 infection centers, 3 regions and 2 host species were analyzed with sixty-five probe-enzyme combinations (13 probes x 5 enzymes) that detected variation within the Douglas-fir-type isolates in the preliminary survey. Ribosomal DNA was very polymorphic among infection centers, but mitochondrial DNA was monomorphic. Eight of the 13 probes detected polymorphism within or among infection centers; three random genomic probes detected variation within the same infection centers. Apart from these rare polymorphisms- -which appear to result from somatic mutation- -infection centers had unitary genotypes that differed from other infection centers with respect to a number of probe-enzyme combinations. This suggests that infection centers are established from single basidiospore infections, and that genetic migration among centers either by vegetative spread or secondary basidiospore establishment is infrequent. Isolates from the two hosts sampled, Douglas-fir (Pseudotsuga menziesii) and mountain hemlock (Tsuga mertensiana), shared a number of polymorphic fragment phenotypes, indicating that the Douglas-fir type lacks strong, qualitative differentiation among these hosts. |
| Genre | Thesis |
| Topic | Conifers -- Diseases and pests |
| Identifier | http://hdl.handle.net/1957/10116 |
