Mating System in Blechnum spicant and Dryopteris affinis ssp. affinis Correlates with Genetic Variability

2013·7.4 MB·English

by  E L Peredo

(2013)
I
Mating System Blechnum and
spicant Dryopteris
in
with Genetic
Correlates Variability
ssp.
affinis affinis
Peredo
E. L.
Department of Ecology and Evolutionary Biology, BioPharm 319, University of Connecticut,
USA
CT
U-3043 75 North Eagleville Road, Storrs, 06269-3043,
M. MEndez-Couz
Laboratory of Neuroscience, Faculty of Psychology, Dpt. Psychology, PI Feijoo s/n 33800 Oviedo,
M. A. Revilla^ and H. FernAndez
Dpt. Biologia de Organismos Sistemas, Universidad de Oviedo, C/ Catedrdtico R. Uria s/n 33071
y
Oviedo, Spain
Abstract.—The monilophytes Blechnum spicant (L.) Sm. and Dryopteris affinis ssp. affinis (Lowe)
Fraser-Jenkins show different reproductive strategies under in vitro conditions. While B. spicant
and with an antheridiogen system promoting outcrossing, D.
exhibits asexual sexual reproduction,
reproduces only asexually through apogamy. Individuals of several populations
affinis ssp. affinis
of these species, collected in Principado de Asturias (Spain), were analyzed to test the influence of
shows
their mating system in the genetic variability displayed by each species. This study that the
concordance with
genetic diversity assessed in populations of each species collected in situ is in
differences among localities. This result indicates high fixation of the detected alleles within each
reproductive system. In the sexual species B. spicant the genetic
locality, as expected for a clonal
was Our confirm the importance of reproduction system in the genetic
diversity higher. results
making consider the definition
diversity present in populations of these fern species essential to
Key Words.—AFLP, Blechnun spicant, clonal growth, Dryopteris affinis, sexual reproduction
new sporophyte can be achieved through asexual or
The
formation of a fern
than gametes
other
reproduction,
During asexual cells
sexual pathways.
without meiosis
through an asexual process or
develop sporophyte
a
The complex Dryopteris (Lowe)
apogamy. fern affinis
called
fertilization
them apogamic
and subspecies, of
diploid triploid all
includes
Fraser-Jenkins
way
Apogamy been reported be a of escaping
has to
(Fraser-Jenkins, 1980).
On
Chao
1980; et ah, 2012). the
by (Fraser-Jenkins,
hybrid alloploids
sterility
Blechnum Sm.
spicant
species
mating system of the fern (L.)
other hand, the
produce male and female
gametophytes that
development of
implies the
which
and form a sexual
archegonia antheridia,
gametes in the sexual organs,
embryo through
fertilization.
[email protected]
* Corresponding author:

AMERICAN FERN VOLUME NUMBER
JOURNAL:
103
(2013)
1
Q
15/1/2009 12/3/2009
1
S
fill
1
Ifl
Jill
|S|
Is - - -
2 2 2
1
N N N N N
W W N W
58.327" 29.706" 50.639" 52.154" 32.083"
0.615"
51.171" 35.684" 30.064"
25' 23' 23' 26' 27' 23'
38' 41' 56'
3° 3° “ ° “ °
1
coordini
(30T)
4810718 0366566 4805620 0362878 4806340 0342852 4810789 0319177 4814827 0362944 4805766
UTM
to
site
road
Purdn
Sampling river,
to
Road
Pur6n
1
1 2 3 8 9
10
B B B D D D
!
1 1,
1
II
1
1

PEREDO ET BLECHNUM AND DRYOPTERIS MATING SYSTEM AND
AL.: GENETIC
VARIABILITY
Hg. 1. Lett: Bar plot ot the proportion ot an individual s ot Blechnum spicant genome belonging
STRUCTURE
to one or other cluster inferred by the analysis. Cluster 1 is represented in green and
AK K
includes individuals from sampled sites B2 (Novales) and B3 (Puron). Right: Plot of for each
value calculated as described in Evanno et al. (2005).
HE
Blechnum and and
calculated for 0.26 (0.07-0.33) for Dryopteris.
I
calculated for each population were: B1 0.20, 030; B2 0.15, 0.22; B3 0.18,
D9 and DlO
D8, Table
0.28; 0.13, 0.18; 0.05, 0.07, 0.02, 0.04 (consult 3 for a
detailed
list).
To between HE, and
test the existence of significant differences the
I,
percentage of polymorphism (%P) values calculated for each species, the
U
Mann-Whitney and were
Krustal-Wallis applied. the
test test Firstly,
suitability of the data to these tests was corroborated by checking whether the
To due
data to a normal distribution. eliminate the possibility of variation to
fit
other causes than the species as a source for the differences in the genetic
variation primer combinations chosen or population related variation)
(e.g.
No
several were performed prior the comparison species to species.
tests
significant differences were detected in any of the comparison within D. affinis
ssp. (data not shown), whereas for B. spicant statistically significant
affinis
=
(%P polymorphism
differences were found only in the percentage of
0.03)
p
No
were found
calculated each primer combination. significant differences
for
using the same approach (Krustal-Wallis test) to the values calculated within
each
species.
The between the values of heterozygosity (HE),
existence of differences
Shannon index and percentage of polymorphism (%P) in D. affinis ssp.
(I),
U
Mann-Whitney
and was using two-tailed
spicant tested test.
B.
affinis
HE
p<0.0001
were detected in each comparison:
Significant differences
%P
and
(Monte p<0.0001 (Monte Carlo p<0.000l);
Carlo p<0.0001);
I
p<0.0001 (Monte p<0.000l).
Carlo
The
and
Blechnum Dryopteris affinis.—
spicant
Genetic structure in
STRUCTURE
was applied the datasets as implied in the
Bayesian-clustering to
program assuming an admixture model, with the assumption of the possibility
AK
Evanno’s indicate the
of mixed ancestry of the individuals. In B. spicant,
AK =2
was and low
possibility of a K=2 grouping as the value for 25.4 values
were AK >2 In each of the 10 replicates
calculated for (<0.5) (Fig. 1).
K=2 from B1 (Nueva) grouped in cluster
the locality
calculated individuals
for
while individuals from B2 (Novales) and B3
with a high probability (>0.904)
1
and
over 0.928
(probability 0.958,
(Road Puron) belonged to cluster 2
to
among from
the individuals
This high degree of similarity
respectively).
populations B2 and B3 was also confirmed by the detected grouping in the

PEREDO ET BLECHNUM AND DRYOPTERIS MATING SYSTEM AND GENETIC
AL.:
VARIABILITY
populations. The high Fst values also corroborate the high local fixation of
variability (D8, 0.538; D9, 0.628; DlO, 0.685). This high degree of similarity
among from same sampling was confirmed by the high
the individuals the site
dendrogram
bootstrap support (>90%) of the different branches in the
PCoA
PAST
calculated with or the grouping in the (data not shown).
(Fig.
3)
Discussion
Blechnum and
spicant
The genetic diversity calculated for the ferns
mechanisms
agreement with the reproductive
Dryopteris in
affinis ssp. affinis is
when and
(Fernandez Revilla, 2003). Also,
observed previously cultured in vitro
sampling.
our importance of small-scale
results indicate the
AFLP
A polymorphism was estimated with for
high percentage of
relatively
and 54,73%
two species of ferns (81.38% for 5. spicant for D. ajfinisssp. affinis)
de no populations were
Principado Asturias;
in a small geographical area in the
km when
found more than 45 However, the distribution of this variation
apart.
polymorphism was
was sampling the
analyzed in relation to the sites,
and even one tenth in the case of D.
reduced half affinis
drastically to at least
11.43% and 6.10% (DlO). In the case of B. spicant a less
(28.66% (D9)
(D8),
polymorphism ranging between
was with recalculated
notable observed,
effect
These changes the percentage of polymor-
45.75% and 60.03% in
(B2) (Bl).
making the variation in each
phism explained by high genetic fixation,
are