Development and characterization of microsatellite markers in Gaultheria pumila Lf. (Ericaceae).

BACKGROUND: Polymorphic microsatellite markers were developed for Gaultheria pumila (Ericaceae) to evaluate genetic diversity and population structure within its native range in Chile. This is a very important Ericaceae endemic to Chile with a large commercial potential. Its resistance to different abiotic conditions makes it a valuable target for genetic improvement. RESULTS: Ten polymorphic simple sequence repeat (SSR) loci were isolated from Gaultheria pumila using new-generation 454 FLX Titanium pyrosequencing technology. The mean number of alleles per locus ranged from 2 to 4. Observed and expected heterozygosity ranged from 0.00 to 1.0 and 0.00 to 0.64, respectively. CONCLUSIONS: From 10 SSR markers developed for G. pumila, 9 markers are promising candidates for analyzing genetic variation within or between natural populations of G. pumila and other species from the same genus.

Development and characterization of microsatellite markers in Gaultheria pumila Lf. (Ericaceae)

BACKGROUND: Polymorphic microsatellite markers were developed for Gaultheria pumila (Ericaceae) to evaluate genetic diversity and population structure within its native range in Chile. This is a very important Ericaceae endemic to Chile with a large commercial potential. Its resistance to different abiotic conditions makes it a valuable target for genetic improvement. RESULTS: Ten polymorphic simple sequence repeat (SSR) loci were isolated from Gaultheria pumila using new-generation 454 FLX Titanium pyrosequencing technology. The mean number of alleles per locus ranged from 2 to 4. Observed and expected heterozygosity ranged from 0.00 to 1.0 and 0.00 to 0.64, respectively. CONCLUSIONS: From 10 SSR markers developed for G. pumila, 9 markers are promising candidates for analyzing genetic variation within or between natural populations of G. pumila and other species from the same genus.

Plastid phylogenomics and adaptive evolution of Gaultheria series Trichophyllae (Ericaceae), a clade from sky islands of the Himalaya-Hengduan Mountains.

Gaultheria series Trichophyllae Airy Shaw is an angiosperm clade of high-alpine shrublets endemic to the Himalaya-Hengduan Mountains and characterized by recent species divergence and convergent character evolution that has until recently caused much confusion in species circumscription. Although multiple DNA sequence regions have been employed previously, phylogenetic relationships among species in the group have remained largely unresolved. Here we examined the effectiveness of the plastid genome for improving phylogenetic resolution within the G. series Trichophyllae clade. Plastid genomes of 31 samples representing all 19 recognized species of the series and three outgroup species were sequenced with Illumina Sequencing technology. Maximum likelihood (ML), maximum parsimony (MP) and Bayesian inference (BI) phylogenetic analyses were performed with various datasets, i.e., that from the whole plastid genome, coding regions, noncoding regions, large single-copy region (LSC) and inverted-repeat region a (IRa). The partitioned whole plastid genome with inverted-repeat region b (IRb) excluded was also analyzed with ML and BI. Tree topologies based on the whole plastid genome, noncoding regions, and LSC region datasets across all analyses, and that based on the partitioned dataset with ML and BI analyses, are identical and generally strongly supported. Gaultheria series Trichophyllae form a clade with three species and one variety that is sister to a clade of the remaining 16 species; the latter comprises seven main subclades. Interspecific relationships within the series are strongly supported except for those based on the coding-region and IRa-region datasets. Eight divergence hotspot regions, each possessing >5% percent variable sites, were screened across the whole plastid genome of the 28 individuals sampled in the series. Results of morphological character evolution reconstruction diagnose several clades, and a hypothesis of adaptive evolution for plant habit is postulated.

Reticulate evolution, cryptic species, and character convergence in the core East Asian clade of Gaultheria (Ericaceae).

Phylogenetic relationships of 84 samples representing 30 species in the core East Asian clade of the wintergreen group of Gaultheria (Angiospermae: Ericaceae: Gaultherieae) were estimated from separate and combined DNA sequence data from five genic regions (ITS, matK, rpl16, trnL-trnF, and trnS-trnG) with parsimony, likelihood and Bayesian analyses. Two major clades were recovered, one comprising several sections and series with leaves generally more than 1 cm long [the ser. Leucothoides sensu lato (s.l.) clade] and another comprising the species of ser. Trichophyllae, with leaves generally less than 1 cm long. The ITS region yielded little phylogenetic resolution, whereas in the combined chloroplast analysis the samples from individual morphospecies in both clades were often nonmonophyletic. This was postulated to result from reticulate evolution in the ser. Leucothoides s.l. clade, particularly in two specific cases of hybridization and a crown clade with likely chloroplast capture following localized introgression. In the ser. Trichophyllae clade, such nonmonophyly was largely attributed to cryptic species and character convergence resulting at least partly from extreme morphological reduction. The relatively low-elevation habitats in which the species of the ser. Leucothoides s.l. clade generally grow are thought to have promoted opportunities for sympatry and reticulation, whereas the high-alpine habitats of ser. Trichophyllae are more likely to have spawned isolated populations and narrow endemism. As in other Sino-Himalayan plant groups, overall low sequence divergence and reticulate evolution suggest rapid radiation in the core East Asian clade of Gaultheria.