Reading Ancient Plants for Climate Solutions Today
- Gary Raham
- May 2
- 4 min read
Updated: May 8
By R. Gary Raham
As a biologist I always enjoy time in the field, but when wind and snow make that a masochistic endeavor, it’s fun to retreat to a museum and explore the life of times past. Botanical museums, called herbaria, house dried plant specimens that may have been collected up to 250 years ago. Herbarium specimens can be both beautiful and practical. Leaves, stems and flowers may curve with a springtime flourish on their paper mounts, but collectors typically harvest extra plant tissues in an envelope that can now be mined for DNA. Researchers like Patricia Lang at the University of California Berkeley are studying plants that have lived through past climate cycles in search of genetic variations that may provide clues for us to survive anthropogenic global warming.
Lang’s efforts are made possible by improvements in genomic analysis technology. Scientists have borrowed nucleic acid splicing tools from bacteria that use them to protect themselves from viruses. Scientists have also greatly improved their methods for reading long stretches of DNA, partly because of all the work done on decoding the human genome since the 90s. Good thing, too, because plant genomes can be extremely long—over 50 times longer than the human genome in the case of the New Caledonian fork fern!
Why do many plants have far longer genomes than their dutiful gardeners? It turns out that plants have often duplicated stretches of their genomes over geological time spans. They also resort to replicating their entire chromosome compliment from time to time—a condition called polyploidy. The reasons for this are often obscure for biologists, but our green friends have used it with amazing success over the eons.
Lang has studied the weed Arabidopsis thaliana (with a short, and now completely sequenced genome) that botanists have used for many years in experiments. Samples of A. thaliana go back centuries in herbarium collections. Specifically, she has been looking at A. thaliana stomates—those tiny holes in leaves that allow for carbon dioxide exchange with the atmosphere. Forty two key genes are involved in stomate development.
As Lang says on her website, “Plants are masters of developmental flexibility…Over 250 years of historical records document this flexibility, and show trends such as advanced flowering (greater than 3 days per 10C warming) or reduced stomatal density (by 40% following 200 years of increasing CO2).” Lang hopes to develop broadly applicable techniques that will promote rapid developmental responses to historical climate change.
A. thaliana has also proved to be an important ally at the Salk Institute’s Harnessing Plants Initiative (HPI). https://www.salk.edu/harnessing-plants-initiative/ They believe they can enhance the powers of a naturally occurring biopolymer called suberin which forms a protective barrier around roots helping them retain moisture, resist pathogens, and store carbon for extended periods.
The late Founding Director of HPI, Joanne Chory, said, “If we can optimize plants’ natural ability to capture and store carbon, we can develop plants that not only have the potential to reduce carbon dioxide in the atmosphere but that can also help enrich soils and increase crop yields.”
The latter is important, because the world’s population is 7.7 billion and growing. Agriculture accounts for 10.6% of greenhouse gas emissions, so anything with the potential for increasing crops without contributing to global warming is a good thing. A gene discovered in A. thaliana helps regulate deeper root systems and enrich suberin. If this genetic toolkit can be transferred to staple crops like rice, sorghum, and soybeans it will give key food crops the ability to trap more carbon below ground while still providing additional food.
The Promise of Duckweed
Herbarium research not your thing? Get outside and admire the beauty and talents of that little pond marvel called duckweed, another common plant with a promising genome. That’s what Todd Michael and other scientists are also working on at the Salk Institute. Duckweed is a rather minimalist plant with 25% fewer protein coding genes than A. thaliana but it still manages to have a high nutritional content, rapid growth, and an adaptability that has made it an attractive potential food source on future space missions.
One of Michael’s long-term goals, using the simplicity of duckweed’s genome as a starting point, is to design entire plant chromosomes with suites of genes that will yield the trifecta of disease resistance, high yield, and much improved carbon storage.
Plants have acquired an amazing toolkit of biochemical pathways over geologic time that have helped them survive and thrive through climate upheavals in the past. Scientists are gaining some of the skills necessary to mine that rich storehouse. They hope to heal some of the consequences of our uniquely human biological success story—and perhaps grow a little wiser, too, in the process.
Gary Raham is a biologist who writes both science fact and science fiction. Not Quite Dead Geniuses at Large on an Angry Planet is a 2024 Colorado Book Award Finalist.
Comentarios