Genetic variation within and among populations of the threatened lichen Lobaria pulmonaria in Switzerland and implications for its conservation
- Author:
- Zoller S., Lutzoni F. & Scheidegger C.
- Year:
- 1999
- Journal:
- Molecular Ecology
- Pages:
- 8: 2049-2059
- Url:
The foliose epiphytic lichen
Lobaria pulmonaria
has suffered a significant decline in
European lowlands during the last decades and therefore is considered as endangered
throughout Europe. An assessment of the genetic variability is necessary to formulate
biologically sound conservation recommendations for this species. We investigated the
genetic diversity of the fungal symbiont of
L. pulmonaria
using 143 specimens sampled
from six populations (two small, one medium, three large) in the lowland, the Jura Mountains,
the pre-Alps and the Alps of Switzerland. Among all nuclear and mitochondrial
regions sequenced for this study, variability was found only in the internal transcribed
spacer (ITS I), with three polymorphic sites, and in the nuclear ribosomal large subunit
(nrLSU), with four polymorphic sites. The variable sites in the nrLSU are all located
within a putative spliceosomal intron. We sequenced these two regions for 81 specimens
and detected six genotypes. Two genotypes were common, two were found only in the
more diverse populations and two were found only in one population each. There was no
correlation between population size and genetic diversity. The highest genetic diversity
was found in populations where the fungal symbiont is reproducing sexually. Populations
with low genetic diversity included only the two same common genotypes. Our
study provides evidence suggesting that
L. pulmonaria
is self-incompatible and heterothallic.
Based on our results we give populations with sexually reproducing individuals
a higher rank in terms of conservation priority than strictly asexual populations. The
remaining lowland populations are so small, that one single catastrophic event such as a
windthrow might destroy the entire population. Hence we suggest augmenting such
populations in size and genetic diversity using small thallus fragments or vegetative
diaspores collected in other populations. As we did not detect any locally adapted
genotypes, these transplants can be taken from any other genetically diverse population
in Switzerland.
Keywords: conservation, genetic variation, lichens, nuclear and mitochondrial DNA sequences,
sexual reproduction.
- Id:
- 1505
- Submitter:
- zdenek
- Post_time:
- Tuesday, 30 November -0001 00:57