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Lopes JML, de Carvalho HH, Zorzatto C, Azevedo ALS, Machado MA, Salimena FRG, Grazul RM, Gitzendanner MA, Soltis DE, Soltis PS, Viccini LF. Genetic relationships and polyploid origins in the Lippia alba complex. Am J Bot 2020; 107:466-476. [PMID: 32115694 DOI: 10.1002/ajb2.1443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Plant genomes vary in size and complexity due in part to polyploidization. Latitudinal analyses of polyploidy are biased toward floras of temperate regions, with much less research done in the tropics. Lippia alba has been described as a tropical polyploid complex with diploid, triploid, tetraploid, and hexaploid accessions. However, no data regarding relationships among the ploidal levels and their origins have been reported. Our goals are to clarify the relationships among accessions of Lippia alba and the origins of each ploidal level. METHODS We investigated 98 samples representing all five geographical regions of Brazil and all ploidal levels using microsatellite (SSR) allelic variation and DNA sequences of ITS and trnL-F. Nine morphological structures were analyzed from 33 herbarium samples, and the chemical compounds of 78 accessions were analyzed by GC-MS. RESULTS Genetic distance analysis, the alignment block pattern, as well as RAxML and Bayesian trees showed that accessions grouped by ploidal level. The triploids form a well-defined group that originated from a single group of diploids. The tetraploids and hexaploid grouped together in SSR and trnL-F analyses. The recovered groups agree with chemical data and morphology. CONCLUSIONS The accessions grouped by ploidal level. Only one origin of triploids from a single group of diploids was observed. The tetraploid origin is uncertain; however, it appears to have contributed to the origin of the hexaploid. This framework reveals linkages among the ploidal levels, providing new insights into the evolution of a polyploid complex of tropical plants.
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Affiliation(s)
- Juliana M L Lopes
- Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, MG, 36036-241, Brazil
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | | | - Cristiane Zorzatto
- Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, MG, 36036-241, Brazil
| | | | | | | | - Richard M Grazul
- Department of Chemistry, Federal University of Juiz de Fora, Juiz de Fora, MG, 36036-241, Brazil
| | | | - Douglas E Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | - Lyderson F Viccini
- Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, MG, 36036-241, Brazil
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Abstract
Invasive species demonstrate rapid evolution within a very short period of time allowing one to understand the underlying mechanism(s). Lantana camara, a highly invasive plant of the tropics and subtropics, has expanded its range and successfully established itself almost throughout India. In order to uncover the processes governing the invasion dynamics, 218 individuals from various locations across India were characterized with six microsatellites. By integrating genetic data with niche modelling, we examined the effect of drift and environmental selection on genetic divergence. We found multiple genetic clusters that were non-randomly distributed across space. Spatial autocorrelation revealed a strong fine-scale structure, i.e. isolation by distance. In addition, we obtained evidence of inhibitory effects of selection on gene flow, i.e. isolation by environmental distance. Perhaps, local adaptation in response to selection is offsetting gene flow and causing the populations to diverge. Niche models suggested that temperature and precipitation play a major role in the observed spatial distribution of this plant. Based on a non-random distribution of clusters, unequal gene flow among them and different bioclimatic niche requirements, we concluded that the emergence of ecotypes represented by two genetic clusters is underway. They may be locally adapted to specific climatic conditions, and perhaps at the very early stages of ecological divergence.
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Affiliation(s)
- Avik Ray
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India Present address: Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Sriramapura, Jakkur Post, Bangalore 560064, India, and Center for Interdisciplinary Studies (CIS), Basudha, Kolkata 700078, India
| | - Rajasri Ray
- Center for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India
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Ray A, Quader S. Genetic diversity and population structure of Lantana camara in India indicates multiple introductions and gene flow. Plant Biol (Stuttg) 2014; 16:651-658. [PMID: 24119091 DOI: 10.1111/plb.12087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 07/05/2013] [Indexed: 06/02/2023]
Abstract
Lantana camara is a highly invasive plant, which has spread over 60 countries and island groups of Asia, Africa and Australia. In India, it was introduced in the early nineteenth century, since when it has expanded and gradually established itself in almost every available ecosystem. We investigated the genetic diversity and population structure of this plant in India in order to understand its introduction, subsequent range expansion and gene flow. A total of 179 individuals were sequenced at three chloroplast loci and 218 individuals were genotyped for six nuclear microsatellites. Both chloroplasts (nine haplotypes) and microsatellites (83 alleles) showed high genetic diversity. Besides, each type of marker confirmed the presence of private polymorphism. We uncovered low to medium population structure in both markers, and found a faint signal of isolation by distance with microsatellites. Bayesian clustering analyses revealed multiple divergent genetic clusters. Taken together, these findings (i.e. high genetic diversity with private alleles and multiple genetic clusters) suggest that Lantana was introduced multiple times and gradually underwent spatial expansion with recurrent gene flow.
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Affiliation(s)
- A Ray
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore - 560065, India
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