Broomrapes (
Though domesticated in eastern North America and widely used as a staple food in the pre-Columbian period [
Unlike most weedy
There are few studies on genetic interactions between wild and weedy forms of parasitic plant species. Knowledge about such interactions is important because wild vegetation may play a role as reservoir of genetic diversity for overcoming genetic resistance mechanisms in the host crops [
Studies on genetic diversity within and between
There is no information on the population structure of
Two field expeditions were conducted in July 2006 and June 2012 along the Black Sea coast of Bulgaria, where the distribution of
Host species, collecting site, characteristics, and number of individuals analyzed for the studied
Population | Host species | Collecting site | Region | Latitude, Longitude, Altitude | Year |
|
---|---|---|---|---|---|---|
| ||||||
CUMBUL-1 |
|
Bulgaria, Burgas, Atanasovsko Lake | South-Eastern Bulgaria | 42°33′02.7′′N; 27°29′24′′E; 14 m | 2006 | 16 |
CUMBUL-2 |
|
Bulgaria, Burgas, Pomorie-Aheloj | South-Eastern Bulgaria | 42°37′02.8′′N; 27°37′31.1′′E; 17 m | 2006 | 30 |
CUMBUL-3 |
|
Bulgaria, Kranevo | North-Eastern Bulgaria | 43°20′05.6′′N; 28°3′41.9′′E; 112 m | 2006 | 6 |
CUMBUL-4 |
|
Bulgaria, Balchik | North-Eastern Bulgaria | 43°24′36.9′′N; 28°9′23.5′′E; 21 m | 2006 | 29 |
CUMBUL-5_1 |
|
Bulgaria, Kavarna, Gorun-Tyulenovo | North-Eastern Bulgaria | 43°29′12.6′′N; 28°31′13.3′′E; 44 m | 2006 | 28 |
CUMBUL-5_2 |
|
Bulgaria, Kavarna, Gorun-Tyulenovo | North-Eastern Bulgaria | 43°29′12.6′′N; 28°31′13.3′′E; 44 m | 2006 | 20 |
CUMBUL-6 |
|
Bulgaria, Burgas, Poda Protected Area | South-Eastern Bulgaria | 42°26′35.91′′N; 27°27′58.64′′E; 7 m | 2012 | 23 |
CUMBUL-7 |
|
Bulgaria, Burgas, Atanasovsko Lake | South-Eastern Bulgaria | 42°33′05.88′′N; 27°29′22.91′′E; 8 m | 2012 | 14 |
|
||||||
| ||||||
CUMBUL-8 |
|
Bulgaria, Sadovo | Central Bulgaria | 42°07′13.49′′N; 24°54′53.40′′E; 156 m | 2012 | 20 |
CUMBUL-9 |
|
Bulgaria, Plodiv | Central Bulgaria | 42°03′35.43′′N; 24°49′26.28′′E; 189 m | 2012 | 20 |
CUMBUL-10 |
|
Bulgaria, Balgarevo | North-Eastern Bulgaria | 43°24′58.14′′N; 28°26′43.83′′E; 81 m | 2012 | 18 |
IASCum-2 |
|
Spain, Sevilla, Écija | Southern Spain | 37°34′24′′N; 5°8′45′′W; 181 m | 2008 | 12 |
IASCum-3 |
|
Spain, Sevilla, Osuna | Southern Spain | 37°15′19′′N; 5°3′49′′W; 304 m | 2008 | 12 |
IASCum-4 |
|
Spain, Cuenca, Montalbo | Central Spain | 39°51′03′′N; 02°39′54′′W; 838 m | 2008 | 12 |
Geographical distribution of
Details of population CUMBUL-1 of
Mature seeds were collected in bulk from 5 to 30 mature plants of populations CUMBUL-1, CUMBUL-2, CUMBUL-4, and CUMBUL-5_1. No mature plants were available at the time of the collection expeditions for the other populations, including the
Frozen tissue was lyophilized and ground to a fine powder. DNA was extracted from individual
For each SSR locus, the number of alleles (Na), observed and expected heterozygosity (Ho and He), and
To evaluate genetic differentiation between populations, initial frequency-based analysis was carried out by calculating pairwise genetic distances between populations using the genetic distance coefficient
To identify genetically homogeneous groups (gene pools), Bayesian model-based clustering algorithms implemented in the software package STRUCTURE ver. 2.3.4 [
Finally, an analysis of molecular variance (AMOVA) [
Mature seeds were collected for wild
Seeds of
All SSR markers were polymorphic (Table
Genetic diversity within each population, measured by the mean number of observed and effective alleles, the expected heterozygosity, and Shannon’s diversity indexes, was in general low, and only one population (CUMBUL-4) contained a substantial number of private alleles (Table
Genetic diversity parameters of
Population |
|
Na (±SE) | Na ≥ 5% (±SE) | Ne (±SE) | Npa (±SE) | Ho (±SE) | He (±SE) |
|
Pairwise differences | Genotypic richness |
|
| |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||
| |||||||||||||
CUMBUL-1 | 66.7 | 1.733 (0.15) | 1.667 (0.13) | 1.391 (0.10) | 0.000 (0.00) | 0.004 (0.01) | 0.229 (0.05) | 0.349 (0.08) | 3.111 (1.66) | 7 | 0.40 | 0.984 (0.01) | 0.992 |
CUMBUL-2 | 86.9 | 2.000 (0.14) | 1.933 (0.15) | 1.521 (0.10) | 0.000 (0.00) | 0.000 (0.00) | 0.297 (0.05) | 0.458 (0.07) | 4.393 (2.20) | 8 | 0.24 | 1.000 (0.00) | 1.000 |
CUMBUL-3 | 0.0 | 1.000 (0.00) | 1.000 (0.00) | 1.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 1 | 0.00 | — | — |
CUMBUL-4 | 53.3 | 1.600 (0.16) | 1.333 (0.13) | 1.145 (0.05) | 0.067 (0.07) | 0.000 (0.00) | 0.105 (0.03) | 0.184 (0.06) | 1.595 (0.96) | 6 | 0.18 | 1.000 (0.00) | 1.000 |
CUMBUL-5_1 | 80.0 | 2.000 (0.17) | 1.867 (0.16) | 1.250 (0.07) | 0.000 (0.00) | 0.032 (0.01) | 0.171 (0.04) | 0.306 (0.06) | 2.449 (1.34) | 11 | 0.37 | 0.776 (0.04) | 0.874 |
CUMBUL-5_2 | 80.0 | 1.933 (0.15) | 1.933 (0.15) | 1.418 (0.10) | 0.000 (0.00) | 0.014 (0.01) | 0.248 (0.05) | 0.400 (0.07) | 3.597 (1.86) | 7 | 0.32 | 0.920 (0.04) | 0.958 |
CUMBUL-6 | 73.3 | 1.800 (0.14) | 1.667 (0.16) | 1.294 (0.10) | 0.000 (0.00) | 0.003 (0.01) | 0.181 (0.05) | 0.300 (0.07) | 2.629 (1.43) | 10 | 0.41 | 0.968 (0.03) | 0.984 |
CUMBUL-7 | 73.3 | 1.800 (0.14) | 1.800 (0.14) | 1.467 (0.12) | 0.000 (0.00) | 0.010 (0.01) | 0.258 (0.05) | 0.398 (0.08) | 3.947 (2.04) | 7 | 0.46 | 0.975 (0.01) | 0.987 |
|
64.2 | 1.733 (0.06) | 1.650 (0.12) | 1.311 (0.03) | 0.008 (0.01) | 0.008 (0.002) | 0.186 (0.02) | 0.299 (0.03) | 2.715 (0.05) | 7.1 | 0.30 | 0.946 | 0.971 |
|
|||||||||||||
| |||||||||||||
CUMBUL-8 | 40.0 | 1.400 (0.13) | 1.133 (0.09) | 1.039 (0.02) | 0.000 (0.00) | 0.021 (0.01) | 0.034 (0.01) | 0.071 (0.03) | 0.446 (0.41) | 3 | 0.11 | 0.194 (0.10) | 0.325 |
CUMBUL-9 | 13.3 | 1.133 (0.09) | 1.133 (0.09) | 1.014 (0.01) | 0.000 (0.00) | 0.000 (0.00) | 0.013 (0.01) | 0.026 (0.02) | 0.195 (0.25) | 2 | 0.05 | 1.000 (0.00) | 1.000 |
CUMBUL-10 | 46.7 | 1.467 (0.13) | 1.467 (0.13) | 1.175 (0.06) | 0.000 (0.00) | 0.015 (0.01) | 0.123 (0.04) | 0.201 (0.06) | 1.825 (1.07) | 8 | 0.41 | 0.915 (0.04) | 0.956 |
|
33.3 | 1.333 (0.10) | 1.244 (0.11) | 1.076 (0.05) | 0.000 (0.00) | 0.012 (0.01) | 0.057 (0.03) | 0.099 (0.05) | 0.822 (0.51) | 4.3 | 0.19 | 0.703 | 0.760 |
IASCum-2 | 0.0 | 1.000 (0.00) | 1.000 (0.00) | 1.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 1 | 0.00 | — | — |
IASCum-3 | 0.0 | 1.000 (0.00) | 1.000 (0.00) | 1.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 0.000 (0.00) | 1 | 0.00 | — | — |
IASCum-4 | 6.7 | 1.067 (0.07) | 1.067 (0.07) | 1.026 (0.03) | 0.000 (0.00) | 0.000 (0.00) | 0.019 (0.02) | 0.030 (0.03) | 0.290 (0.32) | 2 | 0.09 | 1.000 (0.02) | 1.000 |
|
2.2 | 1.022 (0.02) | 1.022 (0.02) | 1.009 (0.01) | 0.000 (0.00) | 0.000 (0.00) | 0.006 (0.01) | 0.010 (0.01) | 0.097 (0.10) | 0.7 | 0.03 |
For measuring differentiation between populations, pairwise
Principal coordinates analysis of pairwise genetic distances among 14
Bayesian-based analysis of the structure of the whole set of populations including those from Spain and Bulgaria with STRUCTURE revealed a close relationship among populations whatever their geographical origin, with an optimal
A more detailed analysis of population structure including only Bulgarian populations was carried out. STRUCTURE analyses indicated the existence of two (
Proportion of membership of each Bulgarian
Population | Genetic group 1 | Genetic group 2 |
---|---|---|
|
0.491 | 0.509 |
|
0.677 | 0.323 |
|
0.984 | 0.016 |
|
0.969 | 0.031 |
|
0.138 | 0.862 |
|
0.239 | 0.76 |
|
0.104 | 0.896 |
|
0.541 | 0.459 |
CUMBUL-8 | 0.023 | 0.977 |
CUMBUL-9 | 0.022 | 0.978 |
CUMBUL-10 | 0.647 | 0.352 |
Results from STRUCTURE and InStruct analyses: (a) population structure obtained from STRUCTURE and InStruct analyses of eleven Bulgarian
Different AMOVA analyses were carried out within the
Analysis of molecular variance (AMOVA) of
Hierarchical structure and source of variation | AMOVA statistics |
|
|
|||
---|---|---|---|---|---|---|
df | Sum of squares | Variance components | % Variance | |||
Bulgarian populations collected on wild hosts (8 populations; 166 individuals) | ||||||
Not structured | ||||||
Among populations | 7 | 491.05 | 1.69 | 53.64 |
|
<0.001 |
Within populations/group | 324 | 473.19 | 1.46 | 46.36 | ||
Structured based on gene poolsb | ||||||
Among groups | 1 | 294.36 | 2.29 | 50.37 |
|
0.032 |
Among populations/group | 6 | 196.69 | 0.80 | 17.56 |
|
<0.001 |
Within populations/group | 324 | 473.19 | 1.46 | 32.07 |
|
<0.001 |
|
||||||
Total of Bulgarian populations (wild and cultivated host) (11 populations; 224 individuals) | ||||||
Not structured | ||||||
Among populations | 10 | 713.97 | 1.74 | 59.54 |
|
<0.001 |
Within populations/group | 437 | 517.64 | 1.18 | 40.46 | ||
Structured based on ecological statusc | ||||||
Among groups | 1 | 93.81 | 0.14 | 4.55 |
|
0.234 |
Among populations/group | 9 | 620.16 | 1.68 | 56.05 |
|
<0.001 |
Within populations/group | 437 | 517.64 | 1.18 | 39.40 |
|
<0.001 |
Structured based on gene poolsd | ||||||
Among groups | 2 | 423.05 | 1.51 | 42.01 |
|
0.002 |
Among populations/group | 8 | 290.91 | 0.90 | 25.05 |
|
<0.001 |
Within populations/group | 437 | 517.64 | 1.18 | 32.94 |
|
<0.001 |
bThe gene pools defined with clustering analyses comprised (i) populations CUMBUL-3 and -4 and (ii) populations CUMBUL-1, -2, -5_1, -5_2, -6, and -7.
cThe structured groups based on the ecological status were (i) wild hosts (populations CUMBUL-1, -2, -3, -4, -5_1, -5_2, -6, and -7) and (ii) cultivated host (sunflower) (populations CUMBUL-8, -9, -10).
dThe gene pools defined with clustering analyses were (i) populations CUMBUL-3, -4, (ii) populations CUMBUL-8 and -9, and (iii) populations CUMBUL-1, -2, -5_1, -5_2, -6, -7, and -10.
A first experiment demonstrated that
Number of emerged
B117b | B206a | |
---|---|---|
CUMBUL-1 |
|
|
CUMBUL-2 |
|
|
CUMBUL-4 |
|
|
CUMBUL-5_1 |
|
|
OC-88 |
|
|
bMeans with different letters for each sunflower cultivar differ significantly (
Number of emerged
B117b | J8281 (B) | AC03-1589 (C) | S1358 (D) | P-1380 (E) | P96 (F) | |
---|---|---|---|---|---|---|
CUMBUL-1 |
|
|
|
NEc | 0a | 0 |
CUMBUL-2 |
|
|
|
|
0a | 0 |
CUMBUL-4 |
|
|
|
NE | 0a | 0 |
CUMBUL-5_1 |
|
|
|
NE |
|
0 |
OC-9 |
|
|
|
|
0a | 0 |
OC-11 |
|
|
|
|
0a | 0 |
OC-13 |
|
|
|
|
0a | 0 |
OC-88 |
|
|
|
|
|
0 |
bMeans with different letters for each sunflower cultivar differ significantly (
cNE = not evaluated.
The genetic structure of
Nevertheless, an important observation in this study was that the genetic structure of wild
Wild and cultivated host plants represent different habitats for parasitic plants, especially when cultivated plants carry qualitative resistance genes, as is the case of the sunflower-
The study of
The authors declare that there is no conflict of interests regarding the publication of this paper.
The research was partially funded by Fundación Ramón Areces, Madrid. R. Pineda-Martos was the recipient of a PhD fellowship from the Spanish National Research Council (CSIC) (JAEPre_08_00370).