Living with a giant, flowering parasite: metabolic differences between Tetrastigma loheri Gagnep. (Vitaceae) shoots uninfected and infected with Rafflesia (Rafflesiaceae) and potential applications for propagation.

MAIN CONCLUSION: Metabolites in Rafflesia-infected and non-infected Tetrastigma were compared which may have applications in Rafflesia propagation. Benzylisoquinoline alkaloids, here reported for the first time in Vitaceae, were abundant in non-infected shoots and may be a form of defense. In Rafflesia-infected shoots, oxylipins, which mediate immune response, were elevated. Endemic to the forests of Southeast Asia, Rafflesia (Rafflesiaceae) is a genus of holoparasitic plants producing the largest flowers in the world, yet completely dependent on its host, the tropical grape vine, Tetrastigma. Rafflesia species are threatened with extinction, making them an iconic symbol of plant conservation. Thus far, propagation has proved challenging, greatly decreasing efficacy of conservation efforts. This study compared the metabolites in the shoots of Rafflesia-infected and non-infected Tetrastigma loheri to examine how Rafflesia infection affects host metabolomics and elucidate the Rafflesia infection process. Results from LC-MS-based untargeted metabolomics analysis showed benzylisoquinoline alkaloids were naturally more abundant in non-infected shoots and are here reported for the first time in the genus Tetrastigma, and in the grape family, Vitaceae. These metabolites have been implicated in plant defense mechanisms and may prevent a Rafflesia infection. In Rafflesia-infected shoots, oxygenated fatty acids, or oxylipins, and a flavonoid, previously shown involved in plant immune response, were significantly elevated. This study provides a preliminary assessment of metabolites that differ between Rafflesia-infected and non-infected Tetrastigma hosts and may have applications in Rafflesia propagation to meet conservation goals.

Characterization of polymorphic microsatellites for the invasive grass Microstegium vimineum (Poaceae).

PREMISE OF THE STUDY: Microsatellite markers were developed for the invasive plant Microstegium vimineum (Poaceae) to assess its population structure and to facilitate tracking of invasion expansion. METHODS AND RESULTS: Using 454 sequencing, 11 polymorphic and six monomorphic microsatellite primer sets were developed for M. vimineum. The primer sets were tested on individuals sampled from six populations in the United States and China. The polymorphic primers amplified di-, tri-, and tetranucleotide repeats with three to 10 alleles per locus. CONCLUSIONS: These markers will be useful for a variety of applications including tracking of invasion dynamics and population genetics studies.

Characterization of polymorphic microsatellites for Tripterygium (Celastraceae), a monospecific genus of medicinal importance.

PREMISE OF THE STUDY: Microsatellite markers were developed for the medicinal plant Tripterygium (Celastraceae) to assess its population structure and to facilitate source tracking of plant materials used for medicinal extracts. METHODS AND RESULTS: Ten microsatellite markers were isolated and characterized in T. wilfordii using an enriched genomic library. The number of alleles per locus ranged from five to 12. Observed and expected heterozygosity ranged from 0.166 to 0.630 and 0.392 to 0.562, respectively. CONCLUSIONS: These markers will be useful for a variety of applications including source tracking of plant materials, resolution of taxonomic issues, and population genetics studies.

Quantitation and Seasonal Variation of Key Odorants in Propolis.

Propolis is a fragrant material produced by bees and is commonly used as an ingredient in food, beverage, and consumer goods industries. Application of a comparative aroma extract dilution analysis (cAEDA) to volatiles isolated from propolis over three consecutive years afforded 48 odorants with flavor dilution (FD) factors ≥ 4, including 21 compounds not previously reported in propolis. Despite differences in FD factors of some compounds, the overall temporal variation in the odorants was low. Compounds with FD ≥ 64 were quantitated by stable isotope dilution assays (SIDAs), and odor activity values (OAVs) were calculated. A total of 22 compounds showed OAVs ≥ 1, including ( E)-isoeugenol (clove; OAV 3700), linalool (floral; OAV 380), butanoic acid (sweaty, rancid; OAV 370), and 3-phenylpropanoic acid (floral; OAV 270). An odor reconstitution model prepared from deodorized beeswax and the 22 odorants in their natural concentrations closely matched the olfactory profile of authentic propolis. The results of this study will help to establish a basis for future research on the variability of propolis sourced from different geographical locations, produced by different bee species, and collected from different botanical sources, all of which are largely unknown.

Science-graphic art partnerships to increase research impact.

Graphics are becoming increasingly important for scientists to effectively communicate their findings to broad audiences, but most researchers lack expertise in visual media. We suggest collaboration between scientists and graphic designers as a way forward and discuss the results of a pilot project to test this type of collaboration.