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Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species.

Jiang D, Feng J, Dong M, Wu G, Mao K, Liu J - BMC Plant Biol. (2016)

Bottom Line: Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis.Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species.In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China.

ABSTRACT

Background: The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents.

Results: We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species.

Conclusions: Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.

No MeSH data available.


Related in: MedlinePlus

Comparisons of soil nitrogen concentration at each depth for the three taxa’s sites. Error bars represent SE. PJ, P. × jrtyschensis; PN, P. nigra; and PL, P. laurifolia. Significant differences in soil nitrogen concentration at each depth for the sites representing the habitat of each of the three taxa as revealed by ANOVA: NS not significant, P > 0.1; *P < 0.05; **P < 0.01; ***P < 0.001
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Fig7: Comparisons of soil nitrogen concentration at each depth for the three taxa’s sites. Error bars represent SE. PJ, P. × jrtyschensis; PN, P. nigra; and PL, P. laurifolia. Significant differences in soil nitrogen concentration at each depth for the sites representing the habitat of each of the three taxa as revealed by ANOVA: NS not significant, P > 0.1; *P < 0.05; **P < 0.01; ***P < 0.001

Mentions: Total soil nitrogen concentration of typical habitats of P. × jrtyschensis differed from those of the two parent species. The typical habitats of P. × jrtyschensis had lower nitrogen concentrations at depths of 0–20 cm, 20–40 cm and 40–70 cm than the habitats of the two parent species (Fig. 7). In addition, we found that soil nitrogen concentrations were significantly different between P. × jrtyschensis habitats and the habitats of the two parent species, with higher probabilities for the greater depths [see Additional files 8, 9 and 10].


Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species.

Jiang D, Feng J, Dong M, Wu G, Mao K, Liu J - BMC Plant Biol. (2016)

Comparisons of soil nitrogen concentration at each depth for the three taxa’s sites. Error bars represent SE. PJ, P. × jrtyschensis; PN, P. nigra; and PL, P. laurifolia. Significant differences in soil nitrogen concentration at each depth for the sites representing the habitat of each of the three taxa as revealed by ANOVA: NS not significant, P > 0.1; *P < 0.05; **P < 0.01; ***P < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4836070&req=5

Fig7: Comparisons of soil nitrogen concentration at each depth for the three taxa’s sites. Error bars represent SE. PJ, P. × jrtyschensis; PN, P. nigra; and PL, P. laurifolia. Significant differences in soil nitrogen concentration at each depth for the sites representing the habitat of each of the three taxa as revealed by ANOVA: NS not significant, P > 0.1; *P < 0.05; **P < 0.01; ***P < 0.001
Mentions: Total soil nitrogen concentration of typical habitats of P. × jrtyschensis differed from those of the two parent species. The typical habitats of P. × jrtyschensis had lower nitrogen concentrations at depths of 0–20 cm, 20–40 cm and 40–70 cm than the habitats of the two parent species (Fig. 7). In addition, we found that soil nitrogen concentrations were significantly different between P. × jrtyschensis habitats and the habitats of the two parent species, with higher probabilities for the greater depths [see Additional files 8, 9 and 10].

Bottom Line: Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis.Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species.In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People's Republic of China.

ABSTRACT

Background: The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents.

Results: We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species.

Conclusions: Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.

No MeSH data available.


Related in: MedlinePlus