Molecular phylogeny, biogeography, and systematics of Dicerandra (Lamiaceae), a genus endemic to the southeastern United States

Abstract

Dicerandra, an endemic mint of the southeastern United States, comprises nine species, all of which are threatened or endangered and restricted to sandhill vegetation and a mosaic of scrub habitats. Molecular phylogenetic analyses of Dicerandra based on data from the nuclear and plastid genomes for all 13 taxa of the genus, identified two strongly supported clades, corresponding to the four annual and to the five perennial species of Dicerandra. However, the nuclear and plastid trees were incongruent in their placement of two perennial taxa, D. cornutissima and D. immaculata var. savannarum, perhaps due to ancient hybridization or to lineage sorting. Based on these analyses, the widespread D. linearifolia is not monophyletic, with populations of D. linearifolia var. linearifolia falling into either western or eastern clades. The western clade, comprising populations of D. linearifolia var. linearifolia and var. robustior, occurs in an area drained by rivers flowing toward the Gulf of Mexico, whereas the eastern clade, comprising populations of D. linearifolia var. linearifolia, D. densiflora, D. odoratissima, and D. radfordiana (i.e., all the annual species), occupies a region drained by rivers flowing to the Atlantic Ocean. Although this pattern of genetic differentiation between populations from these two river drainages has been documented in several animal species, it has not previously been reported for plants. A revised subgeneric classification is presented to reflect the annual and perennial clades.

Secuencias nucleotídicas de la región ITS en familias S1 y PL de maíces poliembriónicos

“…Para la amplificación de la región ITS (Internal Transcribed Spacer) se emplearon los iniciadores N18L (5'-AAGTCGTAACAAGGTTTCCGTAGGTG-'3) (Eldenäs et al, 1998) y C26 A (5'-GTTTCTTTTCCTCCGCT-3') (Oliveira et al, 2007). La amplificación se llevó a cabo en un volumen de 25 µl que contenía: Buffer 1X (Invitrogen, Carlsbad CA), 2 mM MgCl 2 (Invitrogen, Carlsbad CA a), 50 µM dNTPs (Invitrogen, Carlsbad CA.…”

“…Las secuencias obtenidas se compararon mediante la herramienta Basic Local Aligment Search Tool (BLAST) de la base de datos del NCBI, optimizando para las secuencias altamente Amplification and sequencing of ITS. For amplification of ITS region (Internal Transcribed Spacer) N18L primers (5'-AAGTCGTAACAAGGTTTCCGTAGGTG'3) (Eldenäs et al, 1998) and C26 A (5'-GTTTCTTTTCCTCCGCT-'3) (Oliveira et al, 2007); the amplification was carried out in a volume of 25 µl containing: 1X Buffer (Invitrogen, Carlsbad CA), 2 mM MgCl 2 (Invitrogen, Carlsbad CA a), 50 µM dNTPs (Invitrogen, Carlsbad CA), 0.8 pmol of primer N18L and 0.8 pmol of primer C26 A, 2.5 U Taq Platinum (Bioline, London UK); DNA volume was adjusted to reach a concentration of 100 ng. The amplification reaction (PCR) was conducted on a P x 2 Thermal Cycler with an initial step of denaturation at 95 °C for 5 min, followed by 35 cycles (denaturation at 94 °C for 1 min, aligning at 50.3 °C for 1 min and extension at 72 °C for 1 min), and finally a final extension at 72 °C for 5 min.…”

A preliminary phylogeny of the genus Cunila D. Royen ex L. (Lamiaceae) based on ITS rDNA and trnL-F regions

“…We sampled one to two species per genus but often included more, especially for closely related genera. These species were selected based on the ''Mentheae-wide'' analysis conducted by Walker and Sytsma (2007), the molecular phylogeny of Menthinae conducted by Bräuchler et al (2010) and other previous phylogenetic studies (Prather et al, 2002;Edwards et al, 2006;Oliveira et al, 2007).…”

“…Gray (Edwards et al, 2006), Rosmarinus L. (Rosselló et al, 2006), Dicerandra Benth. (Oliveira et al, 2007), Minthostachys (SchmidtLebuhn, 2008), and the phylogenetic study of the subtribe Menthinae (Bräuchler et al, 2010) and tribe Mentheae (Moon et al, 2010).…”

Parent Genotype and Environmental Factors Influence Introduction Success of the Critically Endangered Savannas Mint (Dicerandra immaculata var. savannarum)

“…The plant genus Dicerandra (Lamiaceae) contains four annual and five perennial species that are restricted to scrub and sandhill habitats primarily in Florida [13], [14] and is the highest ranked genus of rare southeastern endemic plants [12]. Six of the nine species have extremely small geographic ranges, there is probably little gene flow between populations, and their habitats are being converted for agricultural and urban development [10], [12], [15]–[17].…”