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Yang R, Deng YW, Liu Y, Zhao J, Bao L, Ge JP, Wang HF. Genetic structure and trait variation within a maple hybrid zone underscore North China as an overlooked diversity hotspot. Sci Rep 2022; 12:13949. [PMID: 35977961 PMCID: PMC9385851 DOI: 10.1038/s41598-022-17538-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/27/2022] [Indexed: 11/30/2022] Open
Abstract
Tertiary relict flora in East Asia can be divided into northern and southern regions. North China is a diversity hotspot because it can be the secondary contact zone of ancient lineages from the two regions. To test the extent of ancient lineages hybridization and distinguish between the putative species pair Acer pictum subsp. mono and Acer truncatum, we conducted genetic and ecological studies within a maple hybrid zone in North China. Our results suggest that the two lineages of Acer coexist in the hybrid zone and that adult and offspring populations show typical bimodal genetic patterns. Hybrid individuals are established at intermediate altitudes between the two parental lineages. Flowering phenology is divergent between lineages, whereas the complex sexual system of Acer may ensure pollination among lineages. Leaf and fruit morphologies are different between the northern and southern origin lineages, corresponding to A. pictum subsp. mono and A. truncatum, respectively. Reduced gene flow between lineages suggests that they should be considered as two species. However, large morphological variations within each species and the existence of hybrids offer low reliability of species identification based solely on morphological traits. Our study underscores North China as an overlooked diversity hotspot that requires further study in the future.
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Affiliation(s)
- Rui Yang
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China.,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China.,College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Ya-Wen Deng
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China.,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China.,College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Yan Liu
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China.,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China.,College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Jing Zhao
- Daheishan Administrative District, Beipiao City, 122000, Liaoning Province, China
| | - Lei Bao
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China.,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China.,College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Jian-Ping Ge
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China.,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China.,College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Hong-Fang Wang
- National Forestry and Grassland Administration Key Laboratory for Conservation Ecology in the Northeast Tiger and Leopard National Park, Beijing, 100875, China. .,Northeast Tiger and Leopard Biodiversity National Observation and Research Station, Beijing, 100875, China. .,College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
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Aerobiological Pollen Deposition and Transport of Fraxinus excelsior L. at a Small Spatial Scale. FORESTS 2022. [DOI: 10.3390/f13030424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The ongoing fragmentation of ash populations due to ash dieback requires an effective gene flow between individuals; thus, investigations on ash pollen transport are essential. In this study, comprehensive aerobiological field experiments at two seed plantations in Baden-Württemberg were conducted in 2019 and 2020 in order to study the influence of phenology and meteorology (especially wind) on pollen transport using self-constructed gravimetric pollen traps located 1.5 and 5 m a.g.l.. Our main objectives were to investigate the local scale dispersion of ash pollen and to evaluate the recommended distance (i.e., 400 m) from seed plantations to other ash trees according to the German Forest Reproduction Act. Our results showed a link between pollen transport and meteorology, the onset of phenological development, and the topography of the plantation. The plantation at Schorndorf was characterized by a slope and associated cold air flows, suggesting that this could be a factor contributing to higher pollen levels at the downslope traps. In addition, in many cases, the cardinal direction associated with the highest pollen impaction was also identical with the predominant wind direction. Analyzing pollen data for single traps in detail, we found that the highest total pollen catch (31%) was measured outside the plantations in 2019, a year with very low flower development. In contrast, most pollen (33%) was caught within the plantation in 2020, which presented a much stronger pollen year than 2019 (with a factor of 11 regarding total sums). This indicates, in the lower pollen year, a potential higher contribution of trees from outside the plantation, and thus it can be recommended that seed harvesting of ash trees in the plantations should preferentially take place in full mast years. Interestingly, the total pollen deposition in Emmendingen at 5 m height showed little difference compared to the traps at 1.5 m height, but there was a large temporal difference pointing to vertical variations in pollen availability. In general, we found that ash pollen was transported for a larger distance than 400 m, but the amount of pollen decreased substantially with increasing distance. At a distance of 200 m, there was already approx. 50% less pollen captured from the air. However, even at a distance of 500 m, more than 10% of the pollen was still captured. In order to ensure cross-pollination of healthy ash trees, the distance of ash individuals or stands should not be too large, and there should be no spatial separation (e.g., by conifer stands).
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Yan S, Yu J, Han M, Michaud JP, Guo LL, Li Z, Zeng B, Zhang QW, Liu XX. Intercrops can mitigate pollen-mediated gene flow from transgenic cotton while simultaneously reducing pest densities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 711:134855. [PMID: 31812403 DOI: 10.1016/j.scitotenv.2019.134855] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
Genetically modified (GM) cotton, engineered to express Bt toxins that protect it from insect damage, has become the most successfully commercialized GM crop in China since its authorization in 1997. In light of the potential ecological consequences of pollen-mediated gene flow (PGF) from GM plants, a two year field trial was conducted to test the effects on PGF of sunflower, Helianthus annuus, buckwheat, Fagopyrum esculentum, and soybean, Glycine max, as intercrops in non-GM cotton fields during 2017 and 2018. DNA tests for hybridized seed were used to estimate rates of PGF in intercrop treatments. PGF was the lowest in cotton intercropped with either buckwheat or sunflower, likely due to the trapping of pollen in these flowers, and/or the diversion of pollinators away from cotton flowers. PGF declined as an exponential function of distance from the GM cotton; Y = -lnx was the model of best fit for estimating pollen dispersal potential. A sunflower intercrop reduced the peak abundance of Aphis gossypii, (Hemiptera: Aphididae), Bemisia tabaci (Hemiptera: Aleyrodidae), and Nysius ericae (Hemiptera: Lygaeidae) on cotton plants, although densities of Tetranychus cinnabarinus (Acari: Tetranychidae), were increased. A buckwheat intercrop had very similar effects on these pests, likely due to attraction of their natural enemies. We conclude that sunflower and buckwheat are suitable intercrops for reducing PGF from GM cotton, and may be useful for reducing PGF from other insect-pollinated GM crops in the agricultural landscape, while simultaneously contributing to control of specific pests. This is the first demonstration, to our knowledge, that intercrops can be used to reduce PGF from transgenic plants.
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Affiliation(s)
- Shuo Yan
- Department of Entomology, China Agricultural University, Beijing 100193, PR China
| | - Jian Yu
- Department of Entomology, China Agricultural University, Beijing 100193, PR China
| | - Min Han
- Department of Entomology, China Agricultural University, Beijing 100193, PR China
| | - J P Michaud
- Department of Entomology, Kansas State University, Agricultural Research Center-Hays, Hays, KS 67601, USA
| | - Li-Lei Guo
- Center of International Cooperation Service, Ministry of Agriculture and Rural Affairs, Beijing 100125, PR China
| | - Zhen Li
- Department of Entomology, China Agricultural University, Beijing 100193, PR China
| | - Bo Zeng
- National Agricultural Technology Extension and Service Center, Beijing 100125, PR China
| | - Qing-Wen Zhang
- Department of Entomology, China Agricultural University, Beijing 100193, PR China
| | - Xiao-Xia Liu
- Department of Entomology, China Agricultural University, Beijing 100193, PR China.
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Ismail SA, Kokko H. An analysis of mating biases in trees. Mol Ecol 2019; 29:184-198. [PMID: 31755136 PMCID: PMC7003921 DOI: 10.1111/mec.15312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/01/2019] [Accepted: 11/20/2019] [Indexed: 11/29/2022]
Abstract
Assortative mating is a deviation from random mating based on phenotypic similarity. As it is much better studied in animals than in plants, we investigate for trees whether kinship of realized mating pairs deviates from what is expected from the set of potential mates and use this information to infer mating biases that may result from kin recognition and/or assortative mating. Our analysis covers 20 species of trees for which microsatellite data is available for adult populations (potential mates) as well as seed arrays. We test whether mean relatedness of observed mating pairs deviates from null expectations that only take pollen dispersal distances into account (estimated from the same data set). This allows the identification of elevated as well as reduced kinship among realized mating pairs, indicative of positive and negative assortative mating, respectively. The test is also able to distinguish elevated biparental inbreeding that occurs solely as a result of related pairs growing closer to each other from further assortativeness. Assortative mating in trees appears potentially common but not ubiquitous: nine data sets show mating bias with elevated inbreeding, nine do not deviate significantly from the null expectation, and two show mating bias with reduced inbreeding. While our data sets lack direct information on phenology, our investigation of the phenological literature for each species identifies flowering phenology as a potential driver of positive assortative mating (leading to elevated inbreeding) in trees. Since active kin recognition provides an alternative hypothesis for these patterns, we encourage further investigations on the processes and traits that influence mating patterns in trees.
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Affiliation(s)
- Sascha A Ismail
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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Peters MAE, Weis AE. Isolation by phenology synergizes isolation by distance across a continuous landscape. THE NEW PHYTOLOGIST 2019; 224:1215-1228. [PMID: 31264221 DOI: 10.1111/nph.16041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/26/2019] [Indexed: 06/09/2023]
Abstract
Pollen is generally dispersed over short distances, which promotes population genetic structure across continuous two-dimensional space. Quantitative genetic variance in flowering time structures mating pools in the temporal dimension, at least with respect to the phenology loci. We asked if these two phenomena, isolation by distance (IBD) and isolation by phenology (IBP), synergistically promote genetic structure. We constructed an individual-based model that tracked genotype frequencies at flowering time and neutral loci across a uniform landscape, over multiple generations, under four mating schemes: panmixia, IBD only, IBP only, and IBP × IBD. IBD × IBP divided the population into spatial clusters of early-, mid-, and late-flowering genotypes and strongly increased its quantitative genetic variance. Flowering time did not cluster under IBP, but its genetic variance increased moderately. IBD induced mild spatial structure in a nonassortative reference trait but did not change its variance. Importantly, the spatial correlation of genotypes at neutral loci was twice as strong under IBD × IBP compared with IBD alone. IBD × IBP also drew neutral loci into gametic disequilibrium with flowering time loci, structuring them temporally. Temporal and spatial mating pool structure promotes local differentiation. This trend would facilitate adaptation on small spatial scales.
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Affiliation(s)
- Madeline A E Peters
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Arthur E Weis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
- Koffler Scientific Reserve, University of Toronto, 17000 Dufferin Street, King City, ON, L7B 1K5, Canada
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