Better pollen barcoding breaking down barriers to plant identification

By Carol Clark | eScienceCommons | April 24, 2017

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"We're interested in pulling pollen off of bees, sequencing that pollen, and figuring out what the bees have been eating," says Emory biologist Berry Brosi. "We can start to construct networks between plants and pollinator species."

Pollen goes back about 491.2 million years, to the Devonian Period. Analysis of its traces have long been used to help solve mysteries related to the history of plants on Earth — from dating rocks for oil exploration to understanding the cultural practices of ancient peoples and investigating past habitats.

Now pollen analysis is poised to play an increasing role in solving modern-day mysteries, aided by gene-sequence libraries and advances in DNA barcoding, or the use of DNA to identify species. DNA metabarcoding enables the analysis of multi-species samples, if those species are contained in a gene-sequence reference library.

The Berry Brosi lab in Emory’s Department of Environmental Sciences recently expanded this gene-sequence library, adding a database for the rbcL gene to the already developed ITS2-gene library to improve the accuracy of plant species identification.

“We’re interested in pulling pollen off of bees, sequencing that pollen, and figuring out what the bees have been eating,” says Brosi, whose lab studies both managed honeybees and wild bees. “We can start to construct networks between plants and pollinator species.”

While Brosi is focused on bee research, pollen analysis contains temporal and spatial signatures that have the long-range potential for a broad range of applications, including forensic investigations. Examples include pinpointing the origin of an illicit drug, testing whether the marketing labels on products such as honey and olive oil match their actual geographic provenance, and determining whether the body of a murder victim had been moved.

The journal Applications in Plant Sciences published the work on the new rbcL library, and the database is publicly available.

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