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No evolutionary shift in the mating system of north American Ambrosia artemisiifolia (Asteraceae) following its introduction to China.

Li XM, Liao WJ, Wolfe LM, Zhang DY - PLoS ONE (2012)

Bottom Line: Specifically, we estimated outcrossing rates in one native and five invasive populations and compared levels of genetic diversity between North America and China.High levels of genetic diversity for both native and invasive populations were found with the unbiased estimate of gene diversity ranging from 0.262-0.289 for both geographic ranges based on AFLP markers.Furthermore, high levels of genetic variation in North America and China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, China.

ABSTRACT
The mating system plays a key role during the process of plant invasion. Contemporary evolution of uniparental reproduction (selfing or asexuality) can relieve the challenges of mate limitation in colonizing populations by providing reproductive assurance. Here we examined aspects of the genetics of colonization in Ambrosia artemisiifolia, a North American native that is invasive in China. This species has been found to possess a strong self-incompatibility system and have high outcrossing rates in North America and we examined whether there has been an evolutionary shift towards the dependence on selfing in the introduced range. Specifically, we estimated outcrossing rates in one native and five invasive populations and compared levels of genetic diversity between North America and China. Based on six microsatellite loci we found that, like the native North American population, all five Chinese populations possessed a completely outcrossing mating system. The estimates of paternity correlations were low, ranging from 0.028-0.122, which suggests that populations possessed ~8-36 pollen donor parents contributing to each maternal plant in the invasive populations. High levels of genetic diversity for both native and invasive populations were found with the unbiased estimate of gene diversity ranging from 0.262-0.289 for both geographic ranges based on AFLP markers. Our results demonstrate that there has been no evolutionary shift from outcrossing to selfing during A. artemisiifolia's invasion of China. Furthermore, high levels of genetic variation in North America and China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process. We suggest that the successful invasion of A. artemisiifolia into Asia was facilitated by repeated introductions from multiple source populations in the native range creating a diverse gene pool within Chinese populations.

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Map of Ambrosia artemisiifolia populations used in this study from China and North America.Population MD, SP, DD, NJ, NC, and LC were used for outcrossing rates estimation with microsatellite; MD, SP, DD, WH, NJ, NC, 1F, 4F, M, and An were for genetic diversity estimation with AFLP.
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pone-0031935-g001: Map of Ambrosia artemisiifolia populations used in this study from China and North America.Population MD, SP, DD, NJ, NC, and LC were used for outcrossing rates estimation with microsatellite; MD, SP, DD, WH, NJ, NC, 1F, 4F, M, and An were for genetic diversity estimation with AFLP.

Mentions: The mating system (selfing rate) was determined using microsatellite markers for one native North American population (LC) and five populations (MD, SP, DD, NJ, and NC) sampled over a large latitudinal gradient in eastern China (Figure 1). For each population, we detected the genotypes of all the seeds randomly sampled from 12 mother plants and 8 mature seeds per mother plants across six SSR loci (GenBank accession numbers: FJ595150, FJ595151, FJ595152, FJ595154, FJ595155, and FJ595156). Total genomic DNA was extracted using a plant genomic DNA extraction kit (Tiangen, China). All the SSR fragments were amplified via standard PCR in 25 µl volume containing 2.5 µl 10×PCR buffer, 2 µl 2.5 mM dNTPs, 1.5 µl 25 mM MgCl2, 0.5 µl 10 mM each fluorescence-labeled forward and reverse primers, 1 U Taq DNA polymerase (TaKaRa, Liaoning, China), 16.8 µl H2O and 1 µl (ca. 10–20 ng) genomic DNA. PCR amplifications were performed in a Bio-Rad thermal cycler as follows: an initial denaturation step at 94°C for 5 min followed by 30 cycles of 30 s at 94°C, 45 s at 50°C and 45 s at 72°C, with a final extension period of 8 min at 72°C. The fluorescence-labeled PCR products were denatured and analyzed on an ABI 3100 genetic analyzer, using the ROX 500 as an internal size standard. The genotypes were scored using GENEMAPPER software version 3.7 (Applied Biosystems).


No evolutionary shift in the mating system of north American Ambrosia artemisiifolia (Asteraceae) following its introduction to China.

Li XM, Liao WJ, Wolfe LM, Zhang DY - PLoS ONE (2012)

Map of Ambrosia artemisiifolia populations used in this study from China and North America.Population MD, SP, DD, NJ, NC, and LC were used for outcrossing rates estimation with microsatellite; MD, SP, DD, WH, NJ, NC, 1F, 4F, M, and An were for genetic diversity estimation with AFLP.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285193&req=5

pone-0031935-g001: Map of Ambrosia artemisiifolia populations used in this study from China and North America.Population MD, SP, DD, NJ, NC, and LC were used for outcrossing rates estimation with microsatellite; MD, SP, DD, WH, NJ, NC, 1F, 4F, M, and An were for genetic diversity estimation with AFLP.
Mentions: The mating system (selfing rate) was determined using microsatellite markers for one native North American population (LC) and five populations (MD, SP, DD, NJ, and NC) sampled over a large latitudinal gradient in eastern China (Figure 1). For each population, we detected the genotypes of all the seeds randomly sampled from 12 mother plants and 8 mature seeds per mother plants across six SSR loci (GenBank accession numbers: FJ595150, FJ595151, FJ595152, FJ595154, FJ595155, and FJ595156). Total genomic DNA was extracted using a plant genomic DNA extraction kit (Tiangen, China). All the SSR fragments were amplified via standard PCR in 25 µl volume containing 2.5 µl 10×PCR buffer, 2 µl 2.5 mM dNTPs, 1.5 µl 25 mM MgCl2, 0.5 µl 10 mM each fluorescence-labeled forward and reverse primers, 1 U Taq DNA polymerase (TaKaRa, Liaoning, China), 16.8 µl H2O and 1 µl (ca. 10–20 ng) genomic DNA. PCR amplifications were performed in a Bio-Rad thermal cycler as follows: an initial denaturation step at 94°C for 5 min followed by 30 cycles of 30 s at 94°C, 45 s at 50°C and 45 s at 72°C, with a final extension period of 8 min at 72°C. The fluorescence-labeled PCR products were denatured and analyzed on an ABI 3100 genetic analyzer, using the ROX 500 as an internal size standard. The genotypes were scored using GENEMAPPER software version 3.7 (Applied Biosystems).

Bottom Line: Specifically, we estimated outcrossing rates in one native and five invasive populations and compared levels of genetic diversity between North America and China.High levels of genetic diversity for both native and invasive populations were found with the unbiased estimate of gene diversity ranging from 0.262-0.289 for both geographic ranges based on AFLP markers.Furthermore, high levels of genetic variation in North America and China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, China.

ABSTRACT
The mating system plays a key role during the process of plant invasion. Contemporary evolution of uniparental reproduction (selfing or asexuality) can relieve the challenges of mate limitation in colonizing populations by providing reproductive assurance. Here we examined aspects of the genetics of colonization in Ambrosia artemisiifolia, a North American native that is invasive in China. This species has been found to possess a strong self-incompatibility system and have high outcrossing rates in North America and we examined whether there has been an evolutionary shift towards the dependence on selfing in the introduced range. Specifically, we estimated outcrossing rates in one native and five invasive populations and compared levels of genetic diversity between North America and China. Based on six microsatellite loci we found that, like the native North American population, all five Chinese populations possessed a completely outcrossing mating system. The estimates of paternity correlations were low, ranging from 0.028-0.122, which suggests that populations possessed ~8-36 pollen donor parents contributing to each maternal plant in the invasive populations. High levels of genetic diversity for both native and invasive populations were found with the unbiased estimate of gene diversity ranging from 0.262-0.289 for both geographic ranges based on AFLP markers. Our results demonstrate that there has been no evolutionary shift from outcrossing to selfing during A. artemisiifolia's invasion of China. Furthermore, high levels of genetic variation in North America and China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process. We suggest that the successful invasion of A. artemisiifolia into Asia was facilitated by repeated introductions from multiple source populations in the native range creating a diverse gene pool within Chinese populations.

Show MeSH
Related in: MedlinePlus