The complete chloroplast genome of Mexican marigold (Tagetes erecta L., Asteraceae).

Tagetes erecta is an important ornamental and medicinal plant indigenous to Mexico and Guatemala. The complete chloroplast genome of T. erecta was newly sequenced in this study. The total chloropalst genome size of T. erecta was 152,055 bp. In total, 123 genes were indetified, including 79 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. Twelve genes are containing introns (ycf3 and clpP contained two introns). The overall GC content of this genome was 37.4%. A further phylogenomic analysis of Asteraceae, including 23 taxa, was conducted for the placement of genus Tagetes. The complete plastome of T. erecta will provide a valuable resource for further genetic conservation, evolution, and molecular breading studies in Asteraceae.

Comparative phylogeography of the Smilax hispida group (Smilacaceae) in eastern Asia and North America--implications for allopatric speciation, causes of diversity disparity, and origins of temperate elements in Mexico.

The Smilax hispida group (Smilacaceae) exhibits a discontinuous distribution in eastern Asia, eastern and western United States, and Mexico. A broad scale phylogeographic analysis was conducted for this group to evaluate the hypotheses of accelerated allopatric divergence in eastern Asia and a northern origin of the temperate elements in Mexico. Phylogeny was inferred using seven plastid and nuclear DNA sequences. Species delineation was assessed using genealogical sorting indices (GSI). Lineage divergence time, haplotype diversification rates, and ancestral distributions were estimated using Bayesian methods. Phylogeographic patterns in eastern Asia and North America were compared by analyzing 539 individuals from 64 populations to assess allopatric diversification. Results strongly supported delineation of six allopatric species, the origin of this group from a Mexican ancestor around 11.42mya, and Mexican origins of the temperate species in Mexico. Significant geographic structure of haplotypes was found in eastern Asia, and greater haplotype diversification rate was observed for the North American lineage. Our data support allopatric speciation in eastern Asia but do not find evidence of an elevated diversification rate. Greater species diversity of the study system in eastern Asia may be due to a longer evolutionary history. Our results do not support northern origins of the Mexican temperate species.