Genetic structure along an altitudinal gradient in Lippia origanoides, a promising aromatic plant species restricted to semiarid areas in northern South America

Abstract

The genetic diversity and population structure of Lippia origanoides, a species of the Verbenaceae family that shows promise as a crop plant, was investigated along an altitudinal gradient in the basin of the Chicamocha River in northeastern Colombia. The economic importance of the species, quality of its essential oils, and the fact that it is restricted to some few semiarid areas in northern South America may put the species at risk in a scenario of uncontrolled harvest of natural populations. Lippia origanoides was sampled along an altitudinal gradient from 365 to 2595 m.a.s.l. throughout Chicamocha River Canyon, a semiarid area in northeastern Colombia. Genetic diversity was assessed by means of AFLP markers. The number of AFLP loci (355) and the number of individuals sampled (173) were sufficient to reliably identify four populations at contrasting altitudes (FST = 0.18, P-value < 0.0000), two populations in the lower basin, one population in the medium basin, and one population in the upper basin, with a low level of admixture between them. In average, genetic diversity within populations was relatively high (Ht = 0.32; I = 0.48); nevertheless, diversity was significantly reduced at higher altitude, a pattern that may be consistent with a scenario of range expansion toward higher elevations in an environment with more extreme conditions. The differences in altitude among the basins in the Chicamocha River seem to be relevant in determining the genetic structure of this species.

Population Differentiation and Species Formation in the Deep Sea: The Potential Role of Environmental Gradients and Depth

“…Numerous studies have documented gradients of lower genetic diversity with increased altitude in plants (reviewed in [135], also [136-138]) and animals (reviewed in [139], also [140-142]). While correlations in terrestrial systems are not always negative or linear, they are frequently accompanied by significant differentiation of highland and lowland clades [143-147], and often implicate the greater importance of vertical vs. horizontal distance.…”

Genetic diversity of <i>Lippia rotundifolia</i> Cham. in Minas Gerais, Brazil

“…The low genetic diversity observed can be explained by the small population density, which made it impossible to keep sampling with the same distance between the individuals as sampled for Lippia origanoides (Suárez et al, 2008), where the authors reported that the sampling between individuals equidistant 1.2 Km, results in different genotypes. Another factor observed in this study was that the temperature may also have contributed to the genotypic adaptation of the plant (Vega-Vela & Sánchez, 2012;Meira, Martins, & Resende, 2017).…”

“…In aromatic species of medicinal interest, studies of genetic structure have concentrated on germplasm of domesticated species or those which chemotypes have already been identified and have consolidated space in the market. Among the species studied are lemon balm (Lippia alba), pepper rosemary (Lippia sidoides) and Mexican oregano (Lippia origanoides Hunth and Lippia graveolens) (Manica-Cattani, Zacaria, Pauletti, Atti-Serafini, & Echeverrigaray, 2009;Vega-Vela & Sánchez, 2012;Rocha et al, 2015).…”

Molecular Analyses used in Genetic Diversity Studies of Bioactive Plants of Verbenaceae and Lamiaceae: A Review

“…Nevertheless, in populations located at higher altitudes, diversity was significantly lower, probably due to more extreme environmental conditions. Therefore, the differences in altitude between the Chicamocha river basins seem to be relevant in determining the genetic structure of this species [100].…”