Genus identification of toxic plant by real-time PCR.

Some plants have toxicities that are dangerous for humans. In the case of poisoning by toxic plants, a rapid and easy screening test is required for accurate medical treatment or forensic investigation. In this study, we designed specific primer pairs for identification of toxic plants, such as subgenus Aconitum, genus Ricinus, genus Illicium, and genus Scopolia, by internal transcribed spacer sequences of nuclear ribosomal DNA. Allied species of target plants, foods, and human DNA were not detected, but each primer pair provided a specific PCR product from the target plant using real-time PCR. This method can detect the subgenus Aconitum, genus Ricinus, and genus Scopolia with template DNA of 10 pg, respectively, and genus Illicium with 1 pg. Furthermore, each primer pair provided the exact PCR product from digested target plants in artificial gastric fluid. When a trace unknown plant sample in forensic investigation is collected from stomach contents, this PCR assay may be useful for screening toxic plants.

Detection of Illicium anisatum as adulterant of Illicium verum.

Chinese Star anise, Illicium verum Hook, is a well known spice in many cultures and has also been used to treat infant colic. Recent publications report that Chinese Star anise might be adulterated with the toxic Japanese Star anise, Illicium anisatum L. We have developed a molecular method that helps with the detection of I. anisatum as adulterant of I. verum. We PCR-amplified the internal transcribed spacer (ITS) region and analyzed it with the endonucleases PSTI and BFMI. Based on fragment length polymorphisms (RFLP), we were able to detect and distinguish between I. anisatum and other Illicium species in powdered samples.

Phylogenetic and evolutionary implications of complete chloroplast genome sequences of four early-diverging angiosperms: Buxus (Buxaceae), Chloranthus (Chloranthaceae), Dioscorea (Dioscoreaceae), and Illicium (Schisandraceae).

We have determined the complete chloroplast genome sequences of four early-diverging lineages of angiosperms, Buxus (Buxaceae), Chloranthus (Chloranthaceae), Dioscorea (Dioscoreaceae), and Illicium (Schisandraceae), to examine the organization and evolution of plastid genomes and to estimate phylogenetic relationships among angiosperms. For the most part, the organization of these plastid genomes is quite similar to the ancestral angiosperm plastid genome with a few notable exceptions. Dioscorea has lost one protein-coding gene, rps16; this gene loss has also happened independently in four other land plant lineages, liverworts, conifers, Populus, and legumes. There has also been a small expansion of the inverted repeat (IR) in Dioscorea that has duplicated trnH-GUG. This event has also occurred multiple times in angiosperms, including in monocots, and in the two basal angiosperms Nuphar and Drimys. The Illicium chloroplast genome is unusual by having a 10 kb contraction of the IR. The four taxa sequenced represent key groups in resolving phylogenetic relationships among angiosperms. Illicium is one of the basal angiosperms in the Austrobaileyales, Chloranthus (Chloranthales) remains unplaced in angiosperm classifications, and Buxus and Dioscorea are early-diverging eudicots and monocots, respectively. We have used sequences for 61 shared protein-coding genes from these four genomes and combined them with sequences from 35 other genomes to estimate phylogenetic relationships using parsimony, likelihood, and Bayesian methods. There is strong congruence among the trees generated by the three methods, and most nodes have high levels of support. The results indicate that Amborella alone is sister to the remaining angiosperms; the Nymphaeales represent the next-diverging clade followed by Illicium; Chloranthus is sister to the magnoliids and together this group is sister to a large clade that includes eudicots and monocots; and Dioscorea represents an early-diverging lineage of monocots just internal to Acorus.